chemistry worksheets handouts

BASIC CONCEPTS PREPARED BY

WORKSHEET HANDOUT 1 OSAMA HASAN

NSTC-6 PREPARATION PROGRAMME | AGA KHAN HIGHER SECONDARY SCHOOL,

KARACHI.

1

MEASUREMENT AND

UNIT CONVERSION (8)

Q 1) Change each of the following

measurements to one in which the unit has

an appropriate SI prefix.

a) 4.54 x 10-9 g b)3.76 x 10

3 m

c)6.34 x 10-6 g d) 1.09 x 10

-9 g

e) 9.01 x 10-3 s

Q2) Carry out the following temperature

conversions.

a) 23.5 °C to °F b) 98.6 °F to °C

c) 212°C to °F d) 173.9 °F to °C

e) -98.0 °C to °F f) -10.0 °F to °C

Q3) Make the following temperature

conversions.

a) The high temperature record for the

continent of Africa is 136 °F, recorded at

Azizia, Libya, in 1922. What is this

temperature in degrees Celsius?

b) In Martian water, the temperature at the

poles drop to -120°C, freezing water vapor

and carbon dioxide from the atmosphere.

What is this temperature in degrees

Fahrenheit?

Q 4) Answer the following temperature

scale questions.

a) A candy recipe calls for heating a sugar

mixture to the “soft ball” stage (234 to 240

°F). Can a laboratory thermometer with a

range of -10 to 110 °C be used for this

measurement?

b) At what temperature do the Fahrenheit

and Celsius readings have the same

numerical value? Can they have the same

value at more than one temperature?

Q 5) Carry out the following conversions.

a)50.0 km to meters b)546 mm to meter

c) 98.5 kg to grams d)47.9 ml to liters

e) 5781JS to ms f) 237 mm to cm

Q6) Carry out the following conversions.

a) 87.6 µg to kg b) 1.00 h to µs

c) 0.0962 km/min to

m/s

d) 55 km/h to m/min

e) 87.4 cm2 to mm

2 f) 46.4 m

3 to liters

Q7) Arrange the following in order of

increasing length (shortest first):

(1) l.21-m chain, (2) 75-in. rope,

(3) 3-ft-5-in. ratllesnake, (4) a yardstick.

Q8) Arrange the following in order of

increasing mass (lightest first):

(1) 5-lb bag of potatoes

(2) 1.65 kg cabbage

(3) 2500 g sugar.

DENSITY (13)

Q9) A 25.0-ml sample of liquid bromine has

a mass 78.0 g. What is the density of the

bromine?

Q10) What is the density of a salt solution if

50.0 ml has a mass of 57.0 g?

Q11) Some metal chips having a volume of

3.29 cm3 are placed on a piece of paper and

weighed. The combined mass is found to be

18.43 g. The paper itself weighs 1.2140 g.

Calculate the density of the metal to the

proper number of significant figures.

Q12) A glass container weighs 48.462 g. A

sample of 4.00 ml of antifreeze solution is

added, and the container plus the antifreeze

weigh 54.51 g. calculate the density of the

antifreeze solution to the proper number of

significant figures.

BASIC CONCEPTS PREPARED BY



KARACHI.

2

Q13) A rectangular block of lead is 1.20 cm

x 2.41cm x 1.80 cm and has a mass of 59.01

g. Calculate the density of lead.

Q14) A rectangular block of gold-colored

material measures 3.00 cm x 1.25 cm x 1.50

cm and has a mass of 28.12 g. Can the

material be gold? The density of gold is 19.3

g/ml.

Q15) What is the mass in grams, of 30.0 ml

of glycerol (a syrup made from pomegranate

juice), which has a density of 1.32 g/ml?

Q16) What is the mass in kg, of 2.75 L of

the liquid glycerol, which has a density of

1.26 g/ml?

Q17) What is the volume of an 898-kg piece

of cast iron (d = 7.76 g/cm3)? If the iron is

formed into a cylindrical bar with a base

area of 1.50 cm2, how long is the bar?

Q18) What is the volume of 5.79 mg of gold

(d = 19.3 g/ml)? If the gold is hammered

into a gold leaf of uniform thickness with an

area of 44.6 cm2, what is the thickness of the

gold leaf?

Q19) A box with a base 0.80 m on a side

and a height of 1.20 m is filled with 3.2 kg

of expanded polystyrene packing material.

What is the bulk density, in g/cm-1 of the

packing material? (The bulk density

includes the air between the pieces of

polystyrene foam.)

Q20) Hylon VII, a starch-based substitute

for polystyrene packing material, has a bulk

density of 12.8 kg/m3. What mass, in grams,

of the material is needed to fill a volume

of2.00 ft3?

Q21) Which of the following items would

be most difficult to lift onto the back of a

pick up truck:

(1) A 100-lb bag of potatoes

(2) A 15-gal plastic bottle filled with water

(3) A 3.0 L flask filled with mercury

(density 13.6 g/cm3)

CHEMICAL LANGUAGE PREPARED BY



KARACHI.

1

MOLECULAR WEIGHTS

FORMULA WEIGHTS (2)

Q1. Calculate the molecular weight or

formula weight of each of the following.

a) C6H5Br b) H3PO4

c) K2Cr207 d) AI2(SO4)3.18H20

Q2. Calculate the molecular weight or

formula weight of each of the following.

a) (NH4)3PO4 b) Na2S2O3

c) C2H5NO2 d) Fe(NO3)3.9H2O

AVOGADRO’S NUMBER &

MOLAR MASSES (3)

Q3. Calculate the average mass in grams of

an atom of:

a) silicon b) copper

c) rhodium d) cobalt

e) strontium f) lead

Q4. Calculate the mass, in grams, of each of

the following:

a) 0.00500 mole MnO2

b) I.12 mole CaH2

c) 0.250 mole C6H1206

d) 4.61 mole AICI3

e) 0.615 mole of chromium (III) oxide

f) 0.158 mole of iodine pentafluoride

Q5. Calculate the amount, in moles, of each

of the following:

a) 98.6 g HNO3 b) 9.45 g CBr4

c) 9.11 g FeSO4 d) 11.8 g Pb(NO3)2

e) 16.3 g of sulfur hexafluoride

f) 25.4 g of lead (II) acetate

g) 35.6 g of iron (III) chloride heptahydrate

h) 75.3 g of cobalt (II) chlorate hexahydrate

PERCENTAGE

COMPOSITION AND

EMPIRICAL FORMULA (9)

Q6. Calculate the mass percent of each

element in each of the following

compounds:

a) BaSiO3 b) C6H5NO2

c) Mg(HCO3)2 d) Al(BrO3)3.9H2O

e)C3H8O f)(NH4)2SO4

g)C6H8N2 h)Ba(ClO4)2.3H2O

Q7. The empirical formula of para-

dichlorobenzene, used as a moth repellent, is

C3H2CI. The molecular weight of the

compound is 147 u. What is the molecular

formula?

Q8. The empirical formula of apigenin, a

yellow dye for wool, is C3H2O. The

molecular weight of the compound is 270 u.

What is the molecular formula?

Q9. Chloroform, an organic solvent, is

10.05% C, 0.84% H and 89.10% Cl by

mass. Determine its empirical formula.

Q10. Urea, used as a fertilizer and in the

manufacture of plastics, is 20.00 % C, 6.71

% H, 46.65% N and 26.64% 0 by mass.

Determine its empirical formula.

Q11. Resorcinol, used in manufacturing

resins, drugs and other products, is 65.44%

C, 5.49% H and 29.06% O by mass.

Determine its empirical formula. The

molecular weight of resorcinol is 110 u.

What is its molecular formula?

Q12. Sodium tetrathionate is formed when

sodium thiosulfate reacts with iodide.

�a2S2O3 + I2

> �axSyOz + �aI

(Not balanced)




KARACHI.

2

Its composition is 17.01% Na, 47.46% S and

35.52% O by mass. Determine its empirical

formula. The formula weight of sodium

tetrathionate is 270 u. What is its actual

formula?

Q13. A 0.1204-g sample of a carboxylic

acid is burned in oxygen to yield 0.2147 g

Co2 and O.0884g H2O. Calculate the mass

percentages of carbon, hydrogen and oxygen

in the compound.

Q14. A 0.0989-g sample of an alcohol is

burned in oxygen to yield 0.2160 g CO2 and

0.1194 g H2O. Calculate the mass

percentages of carbon, hydrogen and oxygen

in the compound.

STOICHIOMETRY OF

CHEMICALREACTIONS (9)

Q15. Consider the equation for the

combustion of octane in oxygen.

2 C8H18 + 25 02

> 16 CO2 + 18 H20

(a) How many moles of C02 are produced

when 2.0 x 1010 moles of C8H18 is burned?

(b) How many moles of oxygen are required

to burn 4.4 x 1010 moles of C8H18?

(c) How many moles of H2O are produced

when 2.0 x 108 moles of C8H18 is burned?

(d) How many moles of C02 are produced

when 4.0 x 108 moles of O2 is consumed?

Q16. Given the equation:

�2 + H2

> �H3 (Not balanced)

(a) How many grams of ammonia can be

made from 440 g H2?

(b) How many grams of hydrogen are

needed to react completely with 892 g N2?

Q17. What mass of oxygen, in grams, can

be prepared from 24.0 g H2O2?

H2O2

> H2O + O2 (Not balanced)

Q18. Toluene and nitric acid are used in the

production of trinitrotoluene (TNT), an

explosive.

C7H8 + H�O3

> C7H5�3O6 + H2O

Toluene TNT

(Not balanced)

(a) What mass of nitric acid is required to

react with 454 g C7H8?

(b) Calculate the mass of TNT that can be

made from 829 g C7H8.

Q19. How many kilograms of quicklime

(calcium oxide) can be made when 4.72 x

109 g of limestone (calcium carbonate) is

decomposed by heating?

CaCO3

> CaO + CO2

Q20. How many grams of nitric acid can be

made from 971 g of ammonia?

�H3 + O2

> H�O3 + H2O

(Not balanced)

Q21. In an oxyacetylene welding torch,

acetylene (C2H2) burns in pure oxygen with

a very hot flame.

C2H2 + O2

>C02 +H2O (Not balanced)

How many grams of oxygen are required to

react with 52.0 g C2H2?

Q22. Kerosene is a mixture of hydrocarbons

used in domestic heating and as a jet fuel.

C14H30 + O2

> CO2 + H2O

(Not balanced)

(a) How many grams of CO2 are produced

by the combustion of 1.00 gal of kerosene?

Assume that kerosene can be represented as

C14H30 and that it has a density of 0.763

g/ml. (l gal = 3.785 L)

(b) How many milliliters of kerosene must

be burnt to produce 1.00 kg CO2?

Q23. Ordinary chalkboard chalk is a solid

mixture with limestone (CaCO3) and

gypsum (CaSO4) as its principal ingredients.




KARACHI.

3

The limestone dissolves in dilute HCI , but

the gypsum does not.

CaCO3 + HCl

> CaCI2 + CO2 + H2O

(Not balanced)

(a) 5.05-g piece of chalk that is 72.0%

CaCO3 dissolved in excess HCl , what mass

of CO2 will be produced?

(b) What is the mass percent CaCO3 present

if a 4.38-g piece of chalk yields 1.31 g CO2

when reacts with excess HCI?

LIMITING REACTANT AND

YIELD CALCULATIONS (7)

Q24. Lithium hydroxide absorbs carbon

dioxide to form lithium carbonate and water.

2 LiOH + CO2

> Li2CO3 + H2O

If a reaction vessel contains 0.150 mole of

LiOH and 0.080 mole of CO2 which

compound is the limiting reactant? How

many moles of Li2CO3 can be produced?

Q25. Boron trifluoride reacts with water to

produce boric acid H3BO3 and fluoroboric

acid (HBF4).

4 BF3 + 3 H2O

> H3BO3 + 3 HBF

If a reaction vessel contains 0.496 mole BF3

and O.313 mole H2O which compound is the

limiting reactant? How many moles of HBF4

can be produced?

Q26. Propane C3H8 burns in oxygen to

produce carbon dioxide and water. If a

reaction vessel contains 4.81 g C3H8 and

16.4 g of which compound is the limiting

reactant? What are the maximum number

grams of carbon dioxide that can be

produced?

Q27. Butane, C4H10 burns in oxygen to

produce carbon dioxide and water. If a

reaction vessel contains 8.37 g C4H10 and

31.9 g O2 which compound is the limiting

reactant? What are the maximum number

grams of carbon dioxide that can be

produced?

Q28. Calculate the theoretical yield of ZnS,

in grams, that can be made from 0.488 g Zn

and 0.503 g S8.

8 Zn + 58

> 8 ZnS

If the actual yield is 0.606 g ZnS, what is the

percent yield?

Q29. Calculate the theoretical yield of

C2H5Cl, in grams, that can be made from

11.3 g of ethanol and 3.48 g PCl3.

3 C2H5OH + PCl3

>

3 C2H5Cl + H3PO3

If the actual yield is 1.24 g C2H5Cl, what is

the percent yield?

Q30. A student prepares ammonium

bicarbonate by the reaction:

�H3 + CO2 + H2O

>�H4HCO3

He uses 14.8 g of NH3 and 41.3g of CO2.

Water is used in excess. What is his actual

yield of ammonium bicarbonate hi obtains

74.7 % yield in the reaction?

SOLUTION

STOICHIOMETRY (20)

Q31. Calculate the molarity of each of the

following solutions:

a) 6 mole HCl in 2.5 L of solution

b) 0.007 mole Li2CO3 in 10.0 ml of solution

c) 2.50 mole H2SO4 in 5 l of solution

d) 0.20 mole C2H5OH in 18.4 ml of solution

e) 8.9 g H2SO4 in 100 ml of solution

f) 439 g of C6H12O6 in 1.25 L of solution

g) 44.3 g KOH in 125 ml of solution

h) 2.46 g H2C2O4 in 750 ml of solution

Q32. How many grams of solute are needed

to prepare each of the following solutions?




KARACHI.

4

a) 2 L of 1.0 M NaOH

b) 10 ml of 4.25 M C6H12O6

c) 250 ml of 2.50 M K2Cr2O7

d) 20 ml of 0.00100 M KMnO4

Q33. How many milliliters of 6 M NaOH

are required to contain 1.25 mole NaOH?

Q34. How many milliliters of 2.5 M NaOH

are required to contain 1.05 mole NaOH?

Q35. How many milliliters of 0.0250

KMnO4 are required to contain 8.10 g of

KMnO4?

Q36. How many milliliters of 4.25 M

C6H12O6 are required to contain 205g of

C6H12O6?

Q37. How many milliliters of 12 M HCl are

required to make 2 L of 1.0 M HCl?

Q38. How many milliliters of 8.89 M HBr

are required to make 2 L of 1.0 M HBr?

Q39. If 25.0 ml of 1.04 M Na2CO3 is diluted

to 0.50 L, what is the molarity of Na2CO3 in

the diluted solution?

Q40. If 50 ml of 19.1 M NaOH is diluted to

2 L, what is the molarity of NaOH in the

diluted solution?

Q41. Which of the following is the

approximate molarity of a solution obtained

by mixing 0.1 L of 0.100 M NH3 and 0.200

L of 0.2 M NH3?

Q42. A stock bottle of potassium hydroxide

solution indicates that the solution is 67%

HNO3 by mass and has a density of 1.40

g/ml. Calculate the molarity of the solution.

Q43. A stock bottle of potassium hydroxide

solution indicates that the solution is 50% by

mass and has a density of 1.52 g/ml.

Calculate the molarity of the solution.

Q44. Calculate the molarity of an HCl

solution if 20 ml of it requires 33.22 ml of

0.1503 M NaOH for its neutralization.

�aOH + HCl

> �aCl + H2O

Q45. Calculate the molarity of an HNO3

solution if 30 ml of it requires 18.34 ml of

0.1044 M KOH for its neutralization.

KOH + H�O3

> K�O3 + H2O

Q46. Calculate the molarity of a Ca(OH)2

solution if 18.5 ml of it requires 28.27 ml of

0.01025 M HCl for its neutralization.

Ca(OH)2 + 2 HCl

> CaCl2 + 2 H2O

Q47. Calculate the molarity of a H2C2O4

solution if 12.5 ml of it requires 25.72 ml of

0.0995 M NaOH for its neutralization.

H2C2O4+ 2 �aOH

>

�a2C2O4 + 2 H2O


H2SO4 are required to react with 10.32 ml of

0.4042 M NaHCO3?

H2SO4+ 2 �aHCO3

>

�a2SO4 + 2 H2O + CO2


H2SO4 are required to react with 30.07 ml

of 0.08872 M Ba(OH)2?

H2SO4+ Ba(OH)3

>

BaSO4 + 2 H2O

Q50. A solution is prepared by dissolving 4

g NAOH in 25 g of water. What mass of

H2SO4 is required in 500g of water to

prepare the solution of same molarity as that

of NaOH solution?




KARACHI.

5

MISCELLANEOUS 1 (23)

Q51. Calculate the molecular weight of

sulphur hexafluoride, SF6, a gas used as an

electric insulator in high-voltage equipment.

Q52. Calculate the formula weight of

ammonium sulfate, a fertilizer commonly

used by home gardeners.

Q53. Calculate the mass, in grams, of 0.250

mole of Na.

Q54. Calculate the number of moles of CO2

present in a 225g sample of the gas.

Q55. How many Cl- ions are present in

1.38g MgCl2?

Q56. What is the mass of a sodium atom, in

grams?


element in ammonium hydroxide (NH4OH).

Q58. What mass of nitrogen, in grams, is

present in 46.34 g ammonium nitrate?

Q59. Phenol, a general disinfectant, is

76.57% C. 6.43% H, and 17.00% O.

Determine its empirical formula.

Q60. Diethylene glycol, used as an

antifreeze, is 45.27% C, 9.50% H and

45.23% O. Determine its empirical formula.

Q61. The empirical formula of

hydroquinone, a chemical used in

photography, is C3H3O, and its molecular

weight is 110u. What is its molecular

formula?

Q62. A 0.1000-g sample of a compound of

C, H and O is burned in oxygen to yield

0.1953g CO2 and 0.1000g H2O. Its

molecular weight had previously been found

to be 90 u.

a. Calculate the mass percent composition

of the compound.

b. What is the empirical formula of the

compound?

c. What is its molecular formula?

Q63. When 0.105 mole propane is burned

in a rich supply of oxygen, how many moles

of oxygen are consumed.

C3H8 + 5O2

> 3CO2 + 4 H2O

Q64. Ammonia, NH3, a common fertilizer,

is made by causing hydrogen and nitrogen to

react at a high temperature and pressure.

How many grams of ammonia can be made

from 60.0g of hydrogen?

Q65. A sheet of iron with a surface area of

525 cm2 is covered with a coating of rust

that has an average thickness of 0.0021 cm.

What mass of a hydrochloric acid solution

that is 15% HCl by mass is required to clean

the surface of the metal by dissolving the

rust? Assume that the rust is iron (III) oxide

and that its density is 5.2 g/cm3.

Fe2O3 + 6HCl

> 2FeCl3 + 3H2O

Q66. Potassium iodide is used as a dietary

supplement to prevent goiter, an iodine

deficiency disease. It is prepared by the

reaction of hydrogen iodide and potassium

hydrogen carbonate.

HI + KHCO3

> KI + H2O + CO2

a. How many grams of KI can be made by

mixing 481 g HI and 318 g KHCO3?

b. Which reactant is in excess, and how

many grams of it remain after the

reaction?




KARACHI.

6

Q67. Ethyl acetate is a solvent used as

fingernail polish remover. How many grams

of acetic acid are needed to prepare 252 g of

ethyl acetate if the expected percent yield is

only 85.0%? Assume that the other reactant,

ethyl alcohol, is present in excess. The

equation for the reaction, carried out in the

presence of H2SO4, is

CH3COOH + C2H5OH

>

CH3COOC2H5 + H2O

Q68. What is the molarity of a solution in

which 333g of potassium hydrogen

carbonate is dissolved in enough water to

make 10.0L of solution?

Q69. How many grams of NaOH are

required to prepare 0.500 L of 6.67M

NaOH?

Q70. A stock bottle of aqueous ammonia

indicates that the solution is 28.0% NH3 by

mass and has a density of 0.898 g/ml.

calculate the molarity of the solution.

Q71. How many milliliters of a 2.00M

CuSO4 stock solution would you use to

prepare 0.250L of 0.400M CuSO4?

Q72. A flask contains 25.00 ml of H2SO4 of

unknown concentration. Titration of the

sample requires 25.20 ml of 0.1000 M

NaOH for neutralization. What is the

molarity of the sulfuric acid solution?

Q73. A flask contains 20.00 ml of 0.1030 M

HCl. What Volume of 0.2010M NaOH must

be added to just neutralize the acid?

�aOH + HCl

> �aCl + H2O




KARACHI.

7


Q74. Calculate, to five significant figures,

the molecular weight of each of the

following compounds.

a) C6H12Br2 b) C2H2Cl2O2

c) H5P3O10 d) C6H4Cl2O2S

Q75. Calculate the formula weight of each

of the following compounds.

a) K2SbF5 b) barium bromate

c) iron(III) phosphate d) NaB(C6H5)4

Q76. Calculate the amount, in moles, of

each of the following:

a) 3.17g Fe b) 76.0 mg of H3PO3

c) 1.65 x 103 kg C4H10 d) 1.99 g of K2CrO4

Q77. Calculate the mass, in grams of each

of the following.

a) 55.5 mole H2O b) 0.0102 mole C4H10O

c) 2.45 x 10-4 mole of

C2H6

d) 2.13 mole of HNO3

Q78. Calculate the number of:

(a) Atom in 6.17g Ca

(b) Molecules in 0.0100g N2

(c) Molecules in 18.5 g butane, C4H10

(d) Atoms in 215 g of sucrose C12H22O11

Q79. Calculate the average mass in grams of

(a) A helium atom

(b) A bismuth atom

(c) A carbon tetrachloride (CCl4) molecule

(d) A propane molecule.


element in

(a) Ammonium sulfate

(b) Urea, CO(NH2)2.

Which compound has the greatest mass

percent nitrogen: ammonium sulfate or

urea?

Q81. People with hypertension (high blood

pressure) are advised to limit the amount of

sodium (actually sodium ion, Na+) in their

diets. Calculate the mass, in mg, of Na+ in

5.00g of sodium hydrogen carbonate

(sodium bicarbonate).

Q82. Mebutamate, a diuretic “water pill”

used to treat hypertension, is 51.70% C,

8.68% H, 12.06% N and 27.55% O.

determine its empirical formula.

Q83. Trinitrotoluene (TNT), an explosive, is

37.01% C, 2.22% H, 18.50% N, and 42.27%

O. determine its empirical formula.

Q84. Ethylene (molecular weight: 28.0u),

cyclohexane (84.0u), and 1-pentene (70.0u)

all have the empirical formula CH2. Give the

molecular formula of each compound.

Q85. A 0.3629-g sample of

tetrahydrocannabinol, a compound of C, H,

and O and the principal active component of

marijuana, is burned in oxygen to yield

1.067 g of carbon dioxide and 0.3120 g of

water.

a. Calculate its mass percent composition.

b.Calculate its empirical formula.

Q86. For the combustion of propane in

example3.16:

a. How many moles of carbon dioxide are

formed when 0.529 mole of C3H8 is

burned?

b.How many moles of water are produced

when 76.2 mole C3H8 is burned?

c. How many moles of carbon dioxide are

produced when 1.010 mole of O2 is

consumed?

Q87. How many grams of magnesium metal

are required to reduce 83.6 g of titanium

(IV) chloride to titanium metal? Magnesium

chloride is other product.




KARACHI.

8

Q88. The decomposition of potassium

chlorate produces potassium chloride and

oxygen gas. How many grams of oxygen

can be made from 2.47 g of potassium

chlorate?

Q89. How many milliliters of liquid water

should be produced by the combustion in

oxygen of 775 ml of liquid octane? Assume

that the volumes of both liquids are

measured at 20 C, where the densities are

0.7025 g/ml for octane and 0.9982 g/ml for

water.

Q90. Hydrogen sulfide is a foul-smelling

gas that was extensively used at one time to

precipitate (separate from solution as solids)

metal sulfides in a laboratory scheme to

identify certain cations in aqueous solutions.

One way to produce the gas is by the time

reaction of iron (II) sulfide with

hydrochloric acid.

FeS + 2HCl

> FeCl2 + H2S

If 10.2g HCL is added to 13.2g FeS, how

many grams of H2S can be formed?

Q91. Isopentyl acetate is the main

component of banana flavoring. Calculate

the theoretical yield of isopentyl acetate that

can be obtained from 20.0 g of isopentyl

alcohol and 25.0 g of acetic acid.

CH3COOH + C5H11OH

>

CH3COO C5H11 + H2O

If the percent yield of the reaction is 90.0%,

what is the actual yield of isopentyl acetate?

Q92. How many grams of isopentyl alcohol

are needed to make 433 g of isopentyl

acetate in the reaction described in exercise

3.19 if the expected yield is 85.0%? Assume

the acetic acid is in excess.

Q93. Calculate the molarity of each of the

following solutions.

a. 18.0 mole H2SO4 in 2.00 L of solution

b.3.00 mole KI in 2.39L of solution

c. 0.206 mole HF in 752 ml of solution

d.0.522g HCl in 0.592 L of solution

e. 4.98g C6H12O6 in 24.7 ml of solution

Q94. How many grams of potassium

hydroxide are required to prepare each of

the following solutions?

a) 2 L of 6M KOH b) 100 ml of 1M KOH

c) 10 ml of 0.1M KOH d) 33 ml of 2.5M KOH

Q95. A stock bottle of aqueous formic acid

indicates that the solution is 90.0% HCOOH

by mass and has a density of 1.20 g/ml.

calculate the molarity of the solution.

Q96. How many milliliters of a 10.15M

NaOH stock solution would you use to

prepare 15.0L of 0.315M NaOH?

Q97. A flask contains 20.00 ml of KOH of

unknown concentration. Titration of the

solution requires 15.62 ml of 0.1104M

H2SO4.

2KOH + H2SO4

> K2SO4 + 2H2O

Calculate the molarity of the KOH.

Q98. How many milliliters of 0.100M

AgNO3 are required to react completely with

750.0 ml of 0.0250M Na2CrO4?

2Ag�O3 + �a2CrO4

>

Ag2CrO4 + 2�a�O3

THE PERIODIC TABLE PREPARED BY



KARACHI.

1

Q1. Predict atleast five general properties of the compounds occupying the indicated positions

in periodic table:

A

C

K B I

H D

L J

G M F

E

Q2. Arrange each set of elements in order of

increasing atomic radius that is, from

smallest to largest:

a) Mg, Si, S b) As, N, P c) As, Se, Sb


decreasing atomic radius:

a) Be, F, N b) Ba, Be, Ca

c) Cl, F, S d) Ca, K, Mg

Q4. Arrange the following species in order

increasing radius: S2-, Ca

2+, Mg

2+, K

+, Se

2+.

Q5. Arrange the following species in order

decreasing radius: Br-, Rb

+, Se

2-, Sr

2+, Y

3+.

Q6. Arrange each set of the elements in

order of increasing first ionization energy:

a) Mg, Si, S b) As, N, P

c) As, Se, Sb


decreasing first ionization energy:

a) Be, F, N b) Ba, Be, Ca

c) P, F, S d) Ca, K, Mg

Q8. In each set, indicate which the more

metallic element is:

a) Ba, Ca b) Sb, Sn

c) Ge, S

Q9. In each sets, indicate the more non-

metallic element:

a) O,P b) As, S c) P, F

Q10. Without referring to any tables or

listing, mark an appropriate location for

each of the following in the blank periodic

table provided:

a) The fourth period noble gas.

b) A fifth period element whose atoms have

three unpaired electrons.

c) The d-block element having one 3-d

electron

d) A p-block element that is a metalloid.

e) A metal that forms the oxide M2O3.

DESCRIPTIVE

QUESTIONS (4)

Q1. Describe the following periodic trends

and their effect on the properties of the

elements in the modern periodic table:

� Atomic/Ionic Radius � Ionization Potential

� Electron Affinity � Electronegativity

THE PERIODIC TABLE PREPARED BY



KARACHI.

2

� Electropositivity � Density

� M.P and B.P � Bond Formation

� Hardness � State

� Nature � Electronic Configuration

Q2. Discuss the factors on which the

following periodic trends depend:

� Atomic/Ionic Radius � Ionization Potential

� Electron Affinity � Electronegativity

� Electropositivity � Density

� M.P and B.P � Bond Formation

� Hardness � State

� Nature � Electronic Configuration

Q3. Discuss the general properties of the

following groups and blocks:

� Group I-A � Group II-A

� Group III-A � Group IV-A

� Group V-A � Group VI-A

� Group VII-A � Group VIII-A

� Transition elements

Q4. Describe the characteristics you can

predict about an element by knowing just its

atomic number of position in periodic table.

STATES OF MATTER PREPARED BY


NSTC-6 PREPARATION PROGRAMME| AGA KHAN HIGHER SECONDARY SCHOOL,

KARACHI.

1 1

DESCRIPTIVE

QUESTIONS (11)

Q1. Describe what a gas is like at the

molecular level?

Q2. Why don’t the molecules of a gas settle

to the bottom of the container?

Q3. Give a kinetic molecular explanation of

the origin of gas pressure.

Q4. State Boyle's law in words and as a

mathematical equation.

Q5. What is the advantage of storing gases

under high pressure (for example, oxygen

used in respiration therapy)?

Q6. What effect will the following changes

have on the volume of a fixed amount of

gas?

(a) An increase in pressure at constant

temperature

(b) A decrease in temperature at constant

pressure

(c) A decrease in pressure coupled with an

increase in temperature

Q7. What effect will the following changes

have on the pressure of a fixed amount of a

gas?

(a) An increase in temperature at constant

volume

(b) Decrease in volume at constant

temperature

(c) An increase in temperature coupled with

a decrease in volume

Q8. According to the kinetic-molecular

theory,

(a) What change in temperature is occurring

if the molecules of a gas begin to move

more slowly, on average?

(b) What change in pressure occurs when

the walls of the container are struck less

often by molecules of the gas?

Q9. Container A has twice the volume but

holds twice as many gas molecules as

container B at the same temperature. Use the

kinetic-molecular theory to compare the

pressures in the two containers.

Q10. For each of the following, indicate in

which container the gas would be expected

to have higher density.

(a) Containers A and B have the same

volume and are at the same temperature, but

the gas in A is at high pressure higher

pressure.

(b) Containers A and B are at the same

pressure and temperature, but the volume of

A is greater than that of B.

(c) Containers A and B are at the same

pressure and volume, but the gas in A is at a

higher temperature.

Q11. Interpret what we mean by temperature

in terms of the kinetic-molecular theory.

PRESSURE (7)

Q12. Calculate the height of a mercury

column that exerts a pressure of 4.36 atm.

Q13. Calculate the height of a mercury

column that exerts a pressure.of213 torr.

Q14. Carry out the following conversions

between pressure units.

a) 721 torr to atm b) 849 torr to atm

c) 985 atm to mmHg

Q15. Carry out the following conversions

between pressure units.

a) 642 torr to kPa b) 105.7 kPa to torr

c) 4.00 atm to mmHg

Q16. A manometer is filled with an oil that

has a density of 0.798 g/ml. Calculate the

gas pressure measured by the manometer if:

a) Barometric pressure is 755 mmHg and

the oil column on the side of the gas flask.

hclosed is 44 mm lower than on the open side,

hopen. b) Barometric pressure is 735 torr and the

oil column on the side of the gas flask,




KARACHI.

2 2

hclosed is 22.3 cm higher than on the open

side, hopen.

Q17. Calculate the heights of columns of

carbon tetra bromide (d = 3.42 g/ml) that

exert the same pressures as a column of

mercury (d = 13.6 g1ml) that is 760 mm

high and a column of water (d = 1.00 glml)

that is 25.5 cm high.

Q18. City fire codes specify the water

pressure that must be maintained at the end

of a water line for example. 35.5 Ib/in2.

Calculate the height of a water column that

exerts a pressure of 35.5 Ib/in2 (Him: 1 atm

= 14.7 Ib/in.2.)

BOYLE’S LAW (6)

Q19. A sample of helium occupies 521 ml

at 1572 torr. Assume that the temperature is

held constant and determine (a) the volume

of the helium at 752 torr; (b) the volume of

the helium at 3.55 atm; (c) the pressure in

torr, if the volume is changed to 315 ml (d)

the pressure in atm if the volume is changed

to 2.75 ml.

Q20. A decomposition chamber used by

deep sea divers has a volume of 10.3 m3

and

operates at an internal pressure of 4.50 atm.

How many cubic meters would the air in the

chamber occupy if it were at normal

atmospheric pressure, assuming no

temperature change?

Q21. A novel energy storage system

involves storing air under high pressure.

(Energy is released when the air is allowed

to expand) How many cubic feet of air

measured at standard atmospheric pressure

of 14.7 pounds per square inch (psi), can be

compressed into a 19-million-ft3

underground cavern at a pressure of 1070

psi?

Q22. Oxygen used in respiratory therapy is

stored at room temperature under a pressure

of 1.50 x 102 atm in gas cylinders with a

volume of 60.0 L.

a) What volume would the gas occupy at a

pressure of 750.0 torr? Assume no

temperature change.

b) If the oxygen flow to the patient is

adjusted to 8.00 L per minute, at room

temperature and 7500 torr, how long will

the tank of gas last?

Q23. A gas is confined in an upright

cylinder closed off by a piston that has a

diameter of 15.0 em. The volume of the gas

is 1.20 L at standard atmospheric pressure.

What total pressure must be exerted on the

piston to cause it to move down 5.25 cm?

Q24. The pressure within a 2.25-L balloon

is 1.10 atm. If the volume of the balloon

increases to 7.05 L. what will be the final

pressure within the balloon, if the

temperature does not change?

CHARLES’ LAW (4)

Q25. A gas at a temperature of 100 °C

occupies a volume of 154 ml. What will the

volume be at a temperature of 10 0 °C,

assuming no change in pressure'?

Q26. A balloon is filled with helium. Its

volume is 5.90 L at 26°C. What will be its

volume at -78 °C, assuming no pressure

change?

Q27. A 567-ml sample of a gas at 305°C

and 1.20 atm is cooled at constant pressure

until its volume becomes 425 ml. What is

the new gas temperature?

Q28. A sample of gas at STP is to be heated

at constant pressure until its volume triples.

What is the new gas temperature?




KARACHI.

3 3

AVAGADRO’S LAW AND

MOLAR VOLUME AT S.T.P (4)

Q29. Which of the following gas samples at

STP contains the greatest number of

molecules?

a) 5.0 g H2 b) 50 L SF6

c)1.0 x 1024

molecules of CO2

Q30.a) How many molecules are present in

475 ml of CO2 at STP?

b) What is the volume occupied by 3.50 x

1024

SO2 molecules at STP?

Q31. What is the mass of 498 L of neon gas

at STP?

Q32. What is the volume occupied by

0.837 g of xenon gas at STP?

THE COMBINED GAS LAW (6)

Q33. A sealed can with an internal pressure

of 721 torr at 25 °C is thrown into an

incinerator operating at 755°C. What will be

the pressure inside the heated can, assuming

the container remains intact during

incineration?

Q34. A fixed amount of He exerts a

pressure of 775 mmHg in a 1.05L container

at 26°C. To what value must the

temperature be changed to reduce the gas

pressure to 725 mmHg? Assume the volume

of gas remains constant

Q35. Suppose we wish to contain a 1.00

mole sample of gas at 1.00 atm pressure and

25 °C. What volume container would we

need?

Q36. At 25°C, the pressure in a gas cylinder

containing 8.00 moles 02 is 5.05 atm. To

maintain both pressure and volume

constant, how many moles of O2 must be

released when the temperature is raised to

235°C?

Q37. If a fixed amount of gas occupies 2.53

m3

at a temperature of -15°C and 191 torr.

What volume will it occupy at 25°C and

1142 torr?

Q38. In terms of pressure (P), volume (V),

Kelvin temperature (T), and amount of gas

(n) sketch a graph of each of the following:

a) V as a function of P, with T and n held

constant

b) n as a function of P, with T and V held

constant

c) T as a function of P, with V and n held

constant

d) N as a function of T with P and V held

constant.

THE IDEAL GAS LAW (8)

Q39. Calculate the volume:

a) In liters, of 1.12 mol H2S at 62°C and

1.38 atm

b) In ml, of 6.00 x 10-3

mol of a gas at 31°C

and 661 mmHg.

Q40. Calculate the volume:

a) In ml, of 3.45 mg O2 at 24°C and 775

mmHg

b) In m3, of 6.92 kg SF6 at 100.0°C and 743

torr.

Q41. Calculate the pressure:

a) In atm, of 4.64 mol CO in a 3.96-L tank

at 29°C

b) In mmHg or 0.0108 mole CH4 in a

0.265L flask at 37°C.

Q42. Calculate the pressure:

(a) In mmHg, of 1.42 g CO2 in a 735ml

flask at -12°C




KARACHI.

4 4

b) In kPa, of 35.5 g N2 in a 5 .35L flask at 0

°C.

Q43. Calculate the mass:

a) In grams, of Kr in 2.22 L at 698 torr and

45°C

b) In milligrams, of CO in 7.45l at 784 torr

and 36°C.

Q44.a) If the gas present in 4.65 L at STP is

changed to temperature of 15°C and a

pressure of 756 torr, what will be the new

volume?

b) What volume will 498 ml of a fixed

amount of gas, measured at 27°C and 722

torr, occupy at STP?

Q45. The interior volume of the Hubert H.

Humphrey Metrodome in Minneapolis is

1.70 x 1010

L. The Teflon coated fiberglass

roof is supported by air pressure provided

by 20 huge electric fans. How many moles

of air are present in the dome if the pressure

is 1.02 atm at 18°C?

Q46. A hyperbaric chamber is an enclosure

containing oxygen at higher-than-normal

pressure used in the treatment of certain

heart and circulatory conditions. What

volume of O2, from a cylinder at 25 °C and

151 atm, is required to fill a hyperbaric

chamber with a volume of 4.20 x 103L to a

pressure of 3.00 atm at 17°C?

MOLAR WEIGHT

DETERMINATIONS (4)

Q47. Calculate the molecular weight of a

gas if 0.549 g occupies 211ml at 747 mmHg

and 24°C.


gas if 0.233 g occupies 334 ml at 721 torr

and 28°C.


liquid that, when vaporized at 98°C and 756

torr, gave 125 ml of vapour with a mass of

0.625 g.


liquid that, when vaporized at 99°C and 716

torr, gave 25 ml of vapour with a mass of

0.625g.

GAS DENSITIES (5) Q51. Calculate the densities of each of the

following in g/dm3:

a) CO at STP

b) Ar at 1.26 atm and 235°C

c) AsH3 at STP

d) N2 at 715 torr and 98°C

Q52. At what temperature will O2 at 0.982

atm pressure have a density of 1.05 g/dm3?

Q53. At what pressure will N2 have a

density of 0.985 g/dm3 at 25°C?

Q54. What must be the molar mass of a gas

found to have a density of 2.57 g/dm3 at 25

°C and 745 torr?'

Q55. Which of the following gases is (are)

more dense than O2 at STP?

a) N2 at STP

b) CO at 0°C and 1.5 atn

c) SO2 at 300°C and 1 atm

d) H2 at 25°C and 10 atm

STOICHIOMETRY OF

GASEOUS REACTIONS (6)

Q56. How many-liters of SO3 can be

produced by the reaction of 1.15 L SO2 and

0.65 L O2, if all three gases are measured at

the same temperature and pressure?

2 S02 + 02

> 2 SO3




KARACHI.

5 5

Q57. What minimum volume of O2 is

required to convert 3.06 L CO to CO2, if all

three gases are measured at the same

temperature and pressure?

CO + ½O2

>CO2

Q58. How many liters of CO2 measured at

22.5°C and 743.5 mmHg are produced in

the decomposition of one metric ton (1.00 x

103 kg) of limestone?

CaC03

> CaO + CO2

Q59. What volume of O2 measured at 22 °C

and 763 torr, is consumed in the combustion

of 7.50 L of C2H6, measured at STP?

2C2H6 + 702

> 4 CO2 + 6 H2O

Q60. How many milligrams of magnesium

metal must react with excess HCl to

produce 28.50 ml of H2, measured at 26 °C

and 758 torr?

Mg + 2 HCI

> MgCl2 + H2

Q61. A 100.0 g sample of aqueous

hydrogen peroxide solution decomposes

over time, producing 2.17 L O2 and 25°C

and 755 torr.

2 H2O2

> 2 H2O + O2

What must have been the mass percent

H2O2 in the solution?

MIXTURE OF GASES (7)

Q62. Calculate the mole fraction of each

gas in the following mixtures:

a) 0.354 g Ar, 0.0521 g Ne, and O.O0419 g

Kr.

b) 1.98 g N2, 0.390 g O2 and 0.0201 g Ar.

Q63. A gas sample has 76.8 mole percent

N2, 20.1 mole percent 02 and 3.1 mole

percent CO2. If the total pressure is 762

mmHg, what are the partial pressures of the

three gases?

Q64. A sample of intestinal gas was

collected and found to consist of 44% CO2,

38% H2, 17% N2, 1.3% 02, and 0.003% CH4

by volume. What is the partial pressure of

each gas, if the total pressure in the intestine

is 818 torr?

Q65. Mixtures of helium and oxygen are

used in· scuba diving. What are the partial

pressures of the two gases in a mixture of

1.96 g He and 60.8 g O2 contained in a

5.00L tank at 25°C?

Q66. Oxygen is collected over water at

30°C and a barometric pressure of 742 torr.

What is the partial pressure of O2 in the

container?

Q67. An oxygen-helium gas sample

collected over water at 23°C exerts a total

pressure of 758 torr. Calculate the mole

fraction of water vapor in the sample.

Q68. Elodea is a green plant that carries out

photosynthesis under water.

6 CO2 + 6 H2O

> C6H12O6 + 6 O2

In an experiment some Elodea produce 1.2

ml of O2 collected over water at 743 torr

and 21°C. What mass of oxygen is

produced? What mass of glucose (C6H12O6)

is produced concurrently?




KARACHI.

6 6


Q69. A Canadian weather report gives the

atmospheric pressure as 100.2 kPa. What is

the pressure in torr?

Q70. Calculate the height of a column of

water that would exert the same pressure as

a column of mercury that is 760 mm high.

Q71. Elephant seals dive to depths as great

as 1250 m. what pressure, in atm, is exerted

by water at that depth?

Q72. A cylinder of oxygen has a volume of

2.00 L. the pressure of the gas is 1360 lb/in2

at 20°C. What volume will the oxygen

occupy at standard atmospheric pressure

(14.7 lb/in.2), assuming there is no

temperature change?

Q73. A weather balloon is partially filled

with helium. On the ground, where the

atmospheric pressure is 748 torr, the volume

of the balloon is 10.0 m3. When the balloon

reaches an altitude of 5300 m, its volume is

found to be 20.2 m3. Assuming that the

temperature remains constant, what must be

the prevailing air pressure at 5300 m?

Q74. A balloon indoors, where the

temperature is 27 °C, has a volume of 2.00

L. what will its volume be outdoors, where

the temperature is -23°C? (Assume no

change in gas pressure.)

Q75. At what temperature, in Kelvin and

degrees Celsius, should the balloon

described in Q74. be held to have a volume

of 2.25 L? (Assume a constant pressure.)

Q76. Calculate the volume occupied by

4.11 Kg of methane gas at STP?

Q77. The flask pictured contains O2, first at

STP and then at then at 100 C. what is the

pressure at 100 C?

Q78. What is the pressure exerted by 0.508

mol O2 in a 15.0 L container at 303 K?

Q79. What is the volume occupied by 16.0

g ethane gas (C2H6) at 720 torr and 18°C?


gas if 0.550 g of the gas occupies 0.200 L at

0.968 atm and 289 K.


liquid which, when vaporized at 100°C and

755 mmHg, yields 185 ml of vapor with a

mass of 0.523 g.

Q82. Calculate the density of methane gas

(CH4), in grams per liter, at 25 C and 0.978

atm.

Q83. Under what pressure must O2 be

maintained at 25°C to have a density of 1.50

g/L?

Q84. What volume of oxygen is required to

burn 0.556 L of propane, if both gases are

measured at the same temperature and

pressure?

C3H8 + 5O2

> 3CO2 + 4 H2O

Q85. In the chemical reaction used in

automotive air-bag safety systems, N2 is

produced by the high- temperature

decomposition of sodium azide, NaN3.

2NaN3

> 2 Na + 3N2

What volume of N2, measured at 25°C and

745 torr, is produced by the decomposition

of 62.5 g NaN3?

Q86. A 1.00L sample of dry air at 25°C

contains 0.0319 moles of N2, 0.00856 mole

of O2, 0.000381 mole of Ar, and 0.00002




KARACHI.

7 7

mole of CO2. Calculate the partial pressure

of N2 in the mixture.

Q87. The main components of dry air, by

volume are N2, 78.08%; O2, 20.95%; Ar,

0.93%; and CO2, 0.04%. What are the

partial pressures of each of the four gases in

a sample of air at 1.000 atm?

Q88. Oxygen is collected over water at

21°C. The total pressure inside the

collection jar is 741 torr. What is the

pressure due to the oxygen alone?

Q89. Hydrogen, produced by the following

reaction, is collected over water at 23°C and

742 torr barometric pressure.

2 Al + 6 HCl

> 2 AlCl3 + 3 H2.

What is the volume of that “wet” gas that

will be collected in the reaction of 1.50g Al

with excess HCl?

Q90. Calculate the relative rates of effusion

of hydrogen and helium under the same

conditions of temperature and pressure.

Q91. A sample of Ar escapes through a tiny

hole in 77.3 s. An unknown gas escape

under the same conditions in 97.6 s.

Calculate the molar mass of the unknown

gas?




KARACHI.

8 8


Q92. Carry out the following conversions.

a. 722 torr to mmHg

b. 98.2 kPa to torr

c. 29.95 in Hg to torr

d. 768 torr to atm

Q93. Calculate the height of a column of

carbon tetrachloride, CCl4 that would exert

the same pressure as a column of mercury

that is 760 mm high. The density of CCl4 is

1.59 g/cm3 and that of Hg is 13.6 g/cm

3.

Q94. A diver reaches a depth of 30.0m.

What pressure, in atm, is exerted by water

at that depth?

Q95. A sample of air occupies 73.3 ml at

98.7 kPa and 0°C. What volume would the

air occupy at 4.02 atm and 0°C?

Q96. A sample of helium occupies 535 ml

at 988 torr and 25°C. if the sample is

transferred to a 1.05-L flask at 25 C, what

will be the gas pressure in the flask?

Q97. A sample of hydrogen occupies 692 L

at 602°C, if the pressure is held constant,

what volume will the gas occupy after

cooling to 23°C?

Q98. Solid carbon dioxide, called “dry ice”,

is useful in maintaining frozen foods

because it vaporizes to CO2 rather than

melting to a liquid. How many kilograms of

“dry ice” can be produced from 5.00 x 103

L CO2 measured at STP?

Q99. Aerosol containers often carry the

warning that they should not be heated.

Suppose such a container was filled with a

gas at 2.5 atm and 22°C and that the

container may rupture if the pressure

exceeds 8.0 atm. At what temperature is that

rupture likely to occur?

Q100. How many moles of nitrogen, N2, are

there in a sample occupies 35.0 L at a

pressure of 3.15 atm and a temperature of

852 K?

Q101. What is the temperature, in degrees

Celsius, at which 15.0 g O2 will exert a

pressure of 785 torr in a volume of 5.00 L?

Q102. How many grams are there in a

sample of N2 that occupies 525 ml at a

pressure of 546 torr and a temperature of

35°C?

Q103. Calculate the molar mass of a gas if

0.440 g occupies 179 ml at 741 mmHg and

86°C?


liquid which, when vaporized at 98°C and

715 mmHg, yields 121 ml of vapor with a

mass of 0.471 g.

Q105. Diacetyl, a substance contributing to

the characteristic flavor and aroma of butter,

consists of 55.80% C, 7.03% H, and

37.17% O. In the gaseous state at 100°C

and 747 mmHg, a 0.3061 g sample occupies

a volume of 111 ml. Establish the molecular

formula of diacetyl.

Q106. Calculate the density of ethane gas

(C2H6), in grams per liter, at 15°C and 748

torr.

Q107. To what temperature must propane

gas (C3H8) at 785 torr be heated to have a

density of 1.51 g/L?

Q108. What volume of methane must

decompose to produce 10.0 L of hydrogen

in the following reaction, if the two gases

are compared at the same temperature and

pressure?

CH4

> C + 2H2




KARACHI.

9 9

Q109. The manufacture of quicklime CaO

for use in construction industry is

accomplished by decomposing limestone

CaCO3 by heating.

CaCO3

> CaO + CO2

How many liters of CO2 at 825°C and 754

torr are produced in the decomposition of

45.8 kg CaCO3?

Q110. How many kilograms of CaO are

formed in the decomposition of CaCO3 if

the volume of CO2 obtained is 1.25 x 104 L

at 825°C and 733 torr?

Q111. Calculate the partial pressure of each

of the other components of the air sample

containing 0.0319 moles of N2, 0.00856

mole of O2, 0.000381 mole of Ar, and

0.00002 mole of CO2. What is the total

pressure exerted by all the gases in the

sample?

Q112. What is the pressure exerted by a

mixture of 4.05 g N2, 3.15g H2, and 6.05g

He when confined to a 6.10 L container at

25°C?

Q113. A sample of expired air (air that has

been exhaled) is composed, by volume, of

the following main components: N2, 74.1%;

O2, 15.0%; H2O, 6.0%; Ar, 0.9%; and CO2,

4.0%. What are the partial pressures of each

of the five gases in the expired air at 37°C

and 1.000 atm?

Q114. A mixture of gases has methane at a

partial pressure of 505 torr, ethane at 201

torr, propane at 43 torr, and butane at 11.2

torr. Calculate the mole fraction of each

component.

Q115. What is the total volume of gas, in

liters, that will be obtained if 1.28g N2 is

collected over water at 21°C and a

barometric pressure of 696 torr?

Q116. Hydrogen gas is collected over water

at 18°C. The total pressure inside the

collection jar is set at the barometric

pressure of 738 torr. If the volume of the

gas is 246 ml, what mass of hydrogen is

collected? What is the mass of the wet gas?

Q117. A sample of KClO3 was decomposed

to potassium chloride and oxygen by

heating. The evolved O2 was collected over

water at 21°C and a barometric pressure of

746 mmHg. A 155 ml volume of the

gaseous mixture was obtained. What mass

of KClO3 was decomposed?

Q118. Calculate the relative rates of

effusion of N2 and A ruder the same

conditions of temperature and pressure.

Q119. A sample of N2 effuse from a tiny

opening in 57 s. an unknown gas escapes

under the same conditions in 83 s. calculate

the molar mass of the unknown gas.

Q120. A sample of O2 effuses from an

orifice in 123 s. how long should it take a

similar sample of methane, CH4, to effuse

under the same conditions?

ATOMIC STRUCTURE PREPARED BY



KARACHI.

1 1

DESCRIPTIVE

QUESTIONS (18)

Q1. What is the nucleus? Describe the

nuclear atom.

Q2. When a light is emitted by an atom,

what change has occurred within an atom?

Q3. When a light is absorbed by an atom,

what change has occurred within an atom?

Q4. Which atom absorbs more energy: One

in which an electron moves from the second

energy level to the third level or an

otherwise identical atom in which an

electron moves from first to the third energy

level? Justify your answer.

Q5. Describe the quantum numbers and list

their possible values.

Q6. How many sublevels are there in an

energy level with each of the following

values of n?

a) n = 2 b) n = 3 c) n = 4

Q7. What is the geometric shape described

by a p-orbital?

Q8. What is the geometric shape described

by an s-orbital? How does a 2s orbital differ

from 1s orbital?

Q9. How many orbitals are there in of the

4f type?

Q10. Is there a 3d subshell in the hydrogen

atom? Explain.

Q11. What is the lowest numbered principal

shell in which p orbitals are found?

Q12. What is the lowest numbered principal

shell in which f orbitals are found?

Q13. If n = 5, what are the possible values

of l? If l = 3, what are the possible values of

m?

Q14. If n = 4, what are the possible values

of l? If l = 1, what are the possible values of

m?

Q15. Indicate, if each of the following is a

permissible set of quantum numbers. If the

set is not permissible, state why is it not

a) n = 2 l = 1 m = +1

b) n = 3 l = 3 m = -3

c) n = 3 l = 2 m = -2

d) n = 0 l = 0 m = 0

e) n = 3 l = 1 m = +2

f) n = 4 l = 3 m = -3

g) n = 3 l = 2 m = +2

h) n = 5 l = 0 m = 0

Q16. Consider the electronic structure of an

atom:

(a) What are the n, l and m quantum

numbers corresponding to the 3s orbital?

(b) List all the possible quantum number

values for an orbital in the 5f subshell.

(c) In what specific subshell, will an

electron having the quantum numbers n = 3,

l = 1 and m = -1 be found?

Q17. Consider the electronic structure of an

atom:

(a) What are the n, l and m quantum

numbers corresponding to the 3p orbital?

(b) List all the possible quantum number

values for an orbital in the 4d subshell.

(c) In what specific subshell, will an

electron having the quantum numbers n = 3,

l = 2 and m = 0 be found?

Q18. The greatest probability of finding an

electron in a small volume element of the 1s

orbital of hydrogen atom is at the nucleus.

Yet the most probable distance of the

electron from the nucleus is 52.9 pm. How

can you reconcile these two statements?

Q19. Show that if an electron in a Hydrogen

atom drops from the level n = 3 to n = 2,

followed by a drop from n = 2 to n = 1, the

total energy emitted is the same if the

electron had fallen directly from the level n

= 3 to n = 1.

Q20. Write down the electronic

classification of all the elements of the

modern periodic table.

THERMOCHEMISTRY PREPARED BY



KARACHI.

1 1

DESCRIPTIVE

QUESTIONS (7)

Q1. You are studying a sample of copper

(II) sulfate solution in a beaker on a ring

stand. The beaker is being heated by the

flame of a Bunsen burner. What is a logical

choice to describe as the system? What type

of a system is it? Describe the surrounding

for your choice of the system.

Q2. Can a system do work and absorb heat

at the same time? Can it do so while

maintain a constant internal energy?

Q3. Can a system do work and give off heat

at the same time? Can it do so while

maintain a constant internal energy?

Q4. How is enthalpy of a system, related to

its internal energy (E)?

Q5. Under what conditions, is the heat of

the reaction equals to the change in internal

energy in a reaction?

Q6. Under what conditions, is the heat of

the reaction equals to the change of enthalpy

in a reaction?

Q7. Upon heating under constant pressure,

solid calcium carbonate decomposes to solid

calcium oxide and carbon dioxide. In one

experiment, 17.8 KJ of heat is added to the

system to decompose 0.100 mole of CaCO3.

Is the reaction exothermic or endothermic?

What is the value of ∆H for the reaction of

one mole of CaCO3?

FIRST LAW OF

THERMODYNAMICS (4)

Q8. What is the change in internal energy

of a system that absorbs 455 J of heat and

does 325 J of work?

Q9. What is the change in internal energy

of a system that has 625 J of work done on it

and gives off 515 J of heat?

Q10. How much work, in joules, must be

involved in a process in which system gives

off 58 cal of heat, if the internal energy of

the system is remained to be unchanged?

Q11. If ∆E for a system is 217 J in a process

in which the system absorbs 185 cal of heat.

How much work in joules, is involved?

ENTHALPY CHNAGES (6)

Q12. At high temperatures water is

decomposed to give hydrogen and oxygen.

2 H2O ───> 2 H2 + O2

Decomposition of 10.0 g H2O in a isobaric

process requires 134 kJ of heat to be

absorbed by the system. Determine if the

reaction is an exothermic or endothermic?

What is the value of q for the reaction, per

mole of water? Is the value of q equals to ∆E

or ∆H? Explain.

Q13. Combustion of 0.144 g of sucrose

(table sugar, C12H22O11) results in release of

2.38 kJ of heat.

C12H22O11 + 12 O2 ───> 12 CO2 + 11 H2O

Is the reaction endothermic or exothermic?

What is the value of q for the reaction, per

mole of sucrose? How would you expect the

values of ∆E and ∆H to compare for this

reaction? Explain

Q14. When 0.0500 mole of solid CaCO3 is

heated in air, it decomposes to solid CaO and

CO2 gas. 8.9 kJ of heat is absorbed. Write

the chemical equation for the decomposition

of one mole of CaCO3 and the value of ∆H.




KARACHI.

2 2

Q15. When 0.200 mole of ethane gas is

burnt in excess oxygen, 312 kJ of heat is

evolved. Write the chemical equation for the

decomposition of one mole of CaCO3 and

the value of ∆H.

Q16. Given the reaction:

3 Fe2O3 + CO ───> 2 Fe3O4 + CO2

∆H°= -- 46kJ

Calculate ∆H for the following reactions:

a) Fe2O3 + �

� CO ───>

�

� Fe3O4 +

�

� CO2

b) Fe3O4 + �

� CO2 ───>

�

� Fe2O3 +

�

� CO

Q17. Given the reaction:

2 �a2O2 + 2 H2O ───> 4 �aOH + O2

∆H°= --109kJ

Calculate ∆H for the following reactions:

a) �a2O2 + H2O ───> 2 �aOH + ½ O2

b) �aOH + �

� O2 ───> ½ �a2O2 + ½ H2O

CALCULATION OF HEATS

REACTION (4)

Q18. Calcium oxide (lime) reacts with water

to form calcium hydroxide (slaked lime).

CaO + H2O ───> Ca(OH)2

∆H°= -- 65.2 kJ

How much heat, in joules is evolved when

0.333 mole Ca(OH)2 is formed?

Q19. Calcium carbide can be made by

heating calcium oxide with carbon.

CaO + 3C ───> CaC2 + CO

∆H°= + 464.8 kJ

How much heat, in joules, is absorbed in a

reaction in which 2.79 mole Carbon is

consumed under these conditions?

Q20. Iron (III) oxide is reduced to iron metal

by reaction with carbon monoxide.

Fe2O3 + 3 CO ───> 2 Fe + 3CO2

∆H°= -- 24.8 kJ

How many kilograms of CO are consumed

when 429 J of heat is released under these

conditions?

Q21. Calcium Carbide reacts with water to

form acetylene (C2H5) a gas used as a fuel in

welding.

CaC2 + 2 H2O ───> C2H2 + Ca(OH)2

∆H°= -- 128.0 kJ

How many kilograms of CaC2 are

consumed in a reaction 3.64 x 104 kJ of heat

under these conditions?

MEASUREMENT OF HEAT (10)

Q22. Calculate the heat capacity of a piece

of iron if a temperature rise from 18°C to

45°C requires 112 J of heat.

Q23. Calculate the heat capacity of a sample

of radiator coolant if temperature rise from -

5°C to 142°C requires 932 J of heat.

Q24. How much heat in kilojoules, is

required to raise the temperature of:

(a) 20 g of water from 20°C to 96°C

(b) 120 g ethanol from -10.5°C to 44.5°C

Q25. How much heat in kilojoules, is

released when the temperature of:

(a) 47 g of water drops from 45.4°C to 10°C

(b) 209 g iron drops from 400°C to 22.6°C

Q26. A 48.7 g block of lead initially at 27°C

absorbs 93.5 J of heat. What is the final

temperature of lead? (Specific Heat of Lead

is 0.128 J/g°C)

Q27. A 454 g iron block initially at 16°C

absorbs 63.9 kJ of heat. What is the final

temperature of iron? (Specific Heat of Iron is

0.449 J/g°C)

Q28. A 10.25 g sample of a metal alloy wire

us heated to 99.10°C. It is then quickly




KARACHI.

3 3

dropped into 20 g of water in a calorimeter.

The water temperature rises from 18.51°C to

22.03°C. Calculate the specific heat of alloy.

Q29. A 2.05 g sample of a metal alloy wire

us heated to 98.88°C. It is then quickly

dropped into 28 g of water in a calorimeter.

The water temperature rises from 19.73°C to

21.23°C. Calculate the specific heat of alloy.

Q30. A 1.35 kg piece of iron is quickly

dropped into 0.817 kg of water, and the

water temperature rises from 23.3°C to

39.6°C. What must have been the initial

temperature?

Q31. A piece of stainless steel is taken from

an oven at 178°C and quickly immersed in

225 ml of water at 25.9°C. The water

temperature rises to 42.4°C. What is the

mass of the piece of steel? (Specific Heat of

Stainless Steel is 0.5 J/g°C)


Q32. A gas does 135 J of work while

expanding, and at the same time it absorbs

156 J of heat. What is the change in internal

energy (E)?

Q33. Use the following equation:

S8 + 4 O2 + 8 Cl2 ───> 8 SOCl2

∆H= -- 1694 kJ

to calculate ∆H for the reaction: �

� S8 + ½ O2 + Cl2 ───> SOCl2

Q34. Given the equation:

H2 + I2 ───> 2HI

∆H= + 52.96 kJ

Calculate ∆H for the reaction:

HI ───> ½ H2 + ½ I2

Q35. What is the enthalpy change associated

with the formation of 5.67 mole HCL in the

reaction?

H2 + Cl2 ───> 2HCl

∆H= -- 184.6 kJ

Q36. Calculate the heat capacity of an

aluminum block if a temperature rise from

22°C to 145°C requires the absorption of 629

J of heat.

Q37. How much heat, in joules and

kilocalories, does it take to raise the

temperature of 225 g of water from 25°C to

100°C?

Q38. How many kilograms of water can be

heated from 5.5°C to 55°C by 9.09 x 1010

J

of heat?

Q39. What will be the final temperature if 25

J of heat is removed from a 5 g silver ring

that is initially at 37°C? (Specific Heat of

Stainless Steel is 0.235 J/g°C)

Q40. A 15.5 g sample of a metal alloy is

heated to 98.9°C and then dropped into 25g

of water in a calorimeter. The temperature of

the water rises from 22.5°C to 25.7°C.

Calculate the specific heat of the alloy.


Q41. In a process in which 89 J of work is

done on a system, 567 J of heat is given off.

What is ∆E of the system?

Q42. Use the equation:

3 O2 ───> 2 O3

∆H= + 285.4 kJ

To calculate ∆H for the reaction: �

� O2 ───> O3

Q43. From the equation:




KARACHI.

4 4

2 Ag2S + 2 H2O ───> 4Ag + 2 H2S + O2

∆H= + 595.5 kJ

Calculate ∆H for the reaction:

Ag + ½ H2S + ½ O2 ───>½ Ag2S + ½ H2O

Q44. What is the enthalpy change when 12.8

H2 reacts with excess Cl2 to form HCl?

H2 + Cl2 ───> 2HCl

∆H= -- 184.6 kJ

Q45. What volume of CH4 measured at 25°C

and 745 torr, must be burnt in excess oxygen

to release 1 x 10 kJ of heat to the

surroundings?

CH4 + 2 O2 ───> CO2 + 2H2O

∆H= -- 890.3 kJ

Q46. Calculate the heat capacity of a sample

of break fluid if a temperature rise from

15°C to 100°C requires the absorption of 911

J of heat.

Q47. How much heat, in calories and

kilocalories, does it take to raise the

temperature of 814 g of water from 18°C to

100°C?

Q48. A 454 g of lead is at an initial

temperature of 22.5°C. What will be the

temperature of the lead, after 4.22 kJ of heat

is added? (Specific Heat of Lead is 0.13

J/g°C)

Q49. How many gram of copper can be

heated from 22.5°C to 35°C by a quantity of

heat sufficient to raise the temperature of 145

g of H2O through the same interval?

(Specific Heat of Copper is 0.385 J/g°C)

Q50. A 23.9 g sample of iridium is heated to

89.7°C and then dropped into 20g of water in

a calorimeter. The temperature of the water

rises from 20.1 to 22.6°C. Calculate the

specific heat of iridium.

ANSWER KEY PREPARED BY

WORKSHEET HANDOUTS OSAMA HASAN

NSTC-6 Preparation Programme | Aga Khan Higher Secondary School, Karachi

NSTC-6 Preparation Programme | Aga Khan Higher Secondary School, Karachi

WORKSHEET

HA�DOUT 2

MISCELLA�EOUS 1

Q51. 146 amu

Q52. 132 amu

Q53. 5.75 g

Q54. 5.11 moles

Q55. 1.74x1022

ions

Q56. 3.8 x 10-23

g

Q57. N= 40% H= 14.2% O=45.71%

Q58. 16.22 g

Q59. C6H6O

Q60. C4H10O3

Q61. C6H6O2

Q62. C=53.3%, H= 11.1% O=35.6%,

C2H5O C4H10O2

Q63. 0.525 moles

Q64. 340 g

Q65. 52 g solution

Q66. 124.02 g 74g

Q67. 202.13 g

Q68. 0.333 M

Q69. 133 g

Q70. 14.8 M

Q71. 50 ml

Q72. 0.05040 M

Q73. 10.25 ml

WORKSHEET

HA�DOUT 2

MISCELLA�EOUS 2

Q74. 244g 129g 258g 211g

Q75. 295g 297g 87g 342g

Q76. 0.06

moles

9.3x10-4

moles

2.8x104

moles

0.01 moles

Q77. 999g 0.75g 7.35x10-3

g 134.2g

Q78. 9.2x1022

atoms

2.5x1020

mol

1.92x1023

mol

1.17x1025

atoms

Q79. 6.6x10-23

g 3.5x10-22

g 2.5x10-22

g 7.3x10-23

g

Q80. N=21.2% H= 6%, S=24.2% O=48.5%

C=20% O=26.6% N=46.6%, H=6.6%),

Urea

Q81. 1370mg

Q82. C5H10NO2

Q83. C2H2NO

Q84. C2H4 C6H12 C5H10

Q85. C=80.2% H=9.4% O=10.4% C21H30O2

Q86. 1.587 moles 304.8

moles

6x10-3

moles

Q87. 21.12g

Q88. 0.96g

Q89. 774 ml

Q90. 4.75g

Q91. 25.15g

Q92. 269.4g

Q93. 9M 1.25M 0.27M 0.024M

1.09M

Q94. 672g 5.6g 0.056g 4.62 g

Q95. 23.5M

Q96. 466ml

Q97. 0.172M

Q98. 375ml

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