simple mcq in chemistry
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Simple MCQ in chemistry for basic studentsTRANSCRIPT
Some exams questions and answers
1-Which of the following does not represent a chemical change?
A)iron rusting B)reaction of sodium metal with water C)dissolving sugar in water D) souring of milk
F)leaves changing color
C) dissolving sugar in water
2-Which of the following does not represent a physical property:
A) boiling point B) odor C) density D) reaction with oxygen. F) solubility in water
Indicate the numbers of protons, neutrons and electrons in the following atoms:
, , ,
A-1 -
Am: 95 protons, 95 electrons, 148 neutrons
C : 6 protons 6 electrons 8 neutrons
Ag: 47 protons 47 electrons 62 neutrons
Zn: 30 protons 30 electrons 34 neutrons
Calculate the molecular mass of each of the following: Li2O, C3H7Br, (CH3CH2CH2)2O, KHSO3, N2O5,
KNO2
(a) -Li2O= (7x2) + 16 = 30 g (b) -C3H7Br = (3x16) + (7x1) + 80= 123 g(c) -(CH3CH2CH2)2O = 102 g (d) -KHSO3 = 39 + 1 + 32 + ( 3x16) = 120 g(e) -N2O5 = ( 2x14) + (sx16) = 108 g(f) -KNO2= 39 + 14 + (2x16) = 85 g
-Calculate the number of moles of CO present in a 125 g sample of
the gas. ) (6 marks)number of moles = mass in grams/molar mass
number of moles of CO = 125/28 = 4.464 mol
Answer whether each of the following statement is true or false:
(Answer 5 only )(15 marks)
a. Bases react with many metals to produce ionic compounds and hydrogen gas. ( false) b. The molarity (M) so called molar concentration.( true ) c. Within a group, electronegativity increases from bottom to top.( true) d. Dilution increases the volume of a solution.( true) e. Acids turn the color of the indicator litmus from red to blue.( false) f. Matter is anything that has mass and occupies a size of space.( true)
5. The metal indium melts at 156ºC. The boiling point of the organic liquid cyclohexanol is 321 ºF. Will indium melt in boiling cyclohexanol? ) (6 marks)F⁰ = ( C⁰ x 1.8 ) + 32 F⁰ = ( 156 x 1.8 ) + 32 = 280.8 F⁰ yes Indium will melt in boiling point of cyclohexanol
6. Determine which of the following represent elements and which do not.
C, CO, Cl, CaCl2, Na, KIC , Cl , Na : are elements , CO , CaCl₂ , KI : are not
7. Which of the following pairs of symbols represent isotopes?
(4 marks )
and , and , and
and , and
and are isotops
8. What are the names and symbols of the SI base units for length,
mass and time?
mass = kg , time = second9. Write: (10 marks)
a) The molecular formula of Phosphorus Pentachloride b) The name of SF6.
)a - (phosphorus pentachloride PCl₅
)b – (sulphur hexafluoride SF₆
10 .Which of the following does not represent a physical property?
A) color B) clarity C) hardness D) melting point E) flammability
E) flammability does not represent a physical property 11 .In the metric system, the prefix micro represents the
multiple A) 10-1. B) 10-2. C) 10-3. D) 10-6. E) 10-9.D)- 10-6.
4-How many g in 580.4 mg?
0.5804 g
5-Which metric prefix would replace the power of ten in 3.68x10ˉ³ m?
3.68 mm
6-Convert 184⁰F to Celsius.
C⁰ = F⁰ - 32/1.8C⁰ = 184-32/1.8 = 48.44
12 .During the course of a day, the difference between the highest and
the lowest temperature for the day was 9°C. What was the
temperature variation in °F? A) 5
B) 9.3 C) 16.6 D) 25.7
E) 34 F) 48.2
°F = (°C x 1.8 ) + 32 °F = ( 9 x 1.8 ) + 32 = 48.2
7-What is the volume in L of 64.0 fluid ounce bottle? (1L=1.o6qt) and (1qt=32fl.oz).
Number of 13 .Which of the following does not vary with
temperature? A) volume
B) mass C) density
D) Kelvin E) °C
B) mass 14 .Aqueous HI is known as
A) hydroiodic acid. B) hydrogen iodide.
C) helium iodide. D) hydrogen monoidide.
E) hyperiodous acid.A) hydroiodic acid.
15 -What the PH of 0.001 M solution of hydrochloric acid?
PH= - log [ H⁺ ]
PH= - log [ 10ˉ³ ]
PH= 3
16 -Calculate the PH value of a solution of sulphoric acid containing 4.9 g per liter of the acid?
-the molar concentration of the acid = 4.9/98=0.05-the molar concentration of hydrogen ions [ H⁺ ]= 0.05 x 2 = 0.1 mol/lit
PH = - log [10ˉ¹]PH= 1
17 -Calculate the PH value of 0.004 solution of acetic acid, where the ionization ratio constant (α) is 25%.
[H⁺ = ] M x α
[H⁺ = ] 0.004 x 0.25 = 10ˉ³PH= - log [ H⁺ ]PH = - log [ 10ˉ³ ]PH = 3
18 -Calculate the PH value of 0.001 M solution of sodium hydroxide?
[OHˉ = ] 10ˉ³
POH = - log [ OHˉ ]POH = - log [ 10ˉ³ ]POH = 3We know that : PH + POH = 14So we write:
PH + 3 = 14PH = 11
Q1-Answer only 15
1)-Which of the following is the correct formula of copper(1) oxide?
a)CuO b)Cu₂O c) Cu(OH)₂ d)Cu₂O₃ e) CuO₂
2)-which of the following is not a physical property?
(a)solid sulphur is yellow
(b)diamond is highly hard
(c)solid iron(Fe) melts at 1533Cº
(d)carbon reacts with oxygen to form carbon dioxde (CO₂)
3 -)What is the right name of the following compound:
BaCl₂
a)Bromuim Chloride , b)Barium Chloride , c)Barium Dichloride
d)Barium(11)Chloride
4-)Which of the following compounds are insoluble in water:
a) CaCl₂ b) NaCl c)Fe(OH)₃ d)FeCl₃ e)Pb(NO₃)₂
f) Ag₂SO₄
5-)Regarding the following reaction, which statement is incorrect?
Cu + 2Ag⁺ → Cu²⁺ + 2Ag
a)copper is oxidized b)copper is reduced c)Ag⁺ is reducing agent d) silver is oxidized
6-)Which of the following has the highest ionization energy value:
a) Cu , b) F , c)Na , d) C , e)O
7-)Which of the following orbitals fills first:
a) 3d b)3p c)4f d)3s e)4d
8 -)Which of the following is the best electrical conductor:
a) 0.6 M HNO₃ b)0.4 M CH₃COOH , c) 1.0 M CH₃CH₂OH d)0.14 M HCl e)0.8 M H₂SO₃
f) 0.80 M NH₄OH
9 -)Predict which of the following bond is the shortest:
10-)Which of the following is the correct Lewis symbol for an atom of Cl:
11)Which of the following bonds is the most polar bond:
a)C-O b)NaBr c)N-O d)Cl-Cl e)S-O
12)- Indicate the oxidation number of the underined atom in each of the following:
a)KMnO₄ b)Mg(ClO₄)₂ C)K₂Cr₂O₇
13)- Which of the following diagrams is not allowed:
14)-Given the following equation:
2H₂(g) + O₂(g) → 2H₂O(l) ΔH⁰ =-571.6kJ/mol
Which statement is incorrect?
a) ΔH⁰ for the reverse reaction is + 571.6 kJ/mol
b) ΔH⁰ for the forming one mole of liquid water is -285.8 kJ/mol
c) ΔH⁰ for the reaction of one-half mole of oxygeb is -285.8kJ/mol
d) The equation forming gaseous water would have different ΔH⁰
e) The standard heat of formation of liquid water is -571.6 kJ/mol.
15)-How many protons, electrons and neutrons are there in the following atoms:
16)- The emperical fornula of dichloro butane is C₂H₄Cl and its molecular mass is 127 u , what is the molecular formula?
17- calculate the formal charge of the nitrogen atom in the compond:
Q2- Identify if the following statements are correct or wrong.
1-( ) the chemical property displayed by the matter as it does not undergo any change in the composition.
2-( ) kandela is a SI unit
3-( ) electron affinity is the energy required to remove one electron from an isolated atom at the gas state and ground state.
4-( ) work is the transfer of energy between the system and its serroundings.
5-( ) the isotopes are atoms of different atoms having the same mass number and different atomic number.
Q2- Follow the instruction given for each question and answer the following :
a- Calculate the consumed amount and the remaining amount of oxygen during the reaction of 14.4 g of C₅H₁₂ in 100 g of oxygen :
C₅H₁₂ + O₂ → CO₂ + H₂O
Answer:
1- we have to balance the equation:
C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O
1- to solve the problem, we write:
C₅H₁₂ + 8O₂ → 5CO₂ + 6H₂O
72 g 8x32g
14.4g x
3- The consumed amount of oxygen=
X= 14.4g x 256 g/72 g = 51.2 g
4- the remainin amount of oxygen=
100 – 51.2 = 48.8 g
b-when 0.20 mol of magnisum Mg is reacted with excess of nitrogen, how many moles of nitrogen are consumed?
3Mg + N₂ → Mg₃N₂
c- what mass of NaOH, in grams is required to prepare 120 ml of 0.20 M of NaOH solution?
d- Calcium oxide reacts with carbon dioxide to form calcium carbonate :
CaO(s) + CO₂(g) → CaCO₃(s) ΔH= - 178.4 kJ
What is the heat evolved in the formation of 500 g of CaCO₃ ?
e-use the following equations:N₂(g) + 2O₂(g) → N₂O₂(g) ΔH=9.2 kJN₂(g) + 2O₂(g) → 2NO₂(g) ΔH=33.2 kJto calculate the enthalpy change for the reaction:2NO₂(g) → N₂O₄(g) ΔH=?
f-write the electron configuration for copper Cu (Z=29) using both : spdf notation and orbital diagram, then the noble gas abbreviation.
g- use the lewis theory to show the ionic bond of Ca & Cl .
h- write the resonance structures of SO₂ accourding to Lewis's theory, the show the formal charge of each atom.
i- how would you prepare 500 ml of an aqueous solution that is 3.0 % KOH by mass.
j- what is the concentration in ppm of 0.40 g of NO₃ˉ in one litter of water.
Answer:
1 ppm = 1 mg/liter
The number of ppm ( miligrams ) per liter=
0.40x1000= 400 ppm
k-what is the molality of sodium chloride NaCl in a solution containing 117 g of this salt in 360 ml of water.
Answer :
Molality = the number of moles of the solute/the mass of the solvent in Kg
1- the molar mass of NaCl = 23 + 35.5 = 58.5 g
2- the number of moles ( NaCl) = 117/58.5 =2 mol
3- the mass of the solvent( H₂O)=360g = 0.360 Kg
4- the molality= 2/0.360=
l-Arrange the following in order of increasing the first ionization energy:
C , N, F , O , Be
m-Arrange the following in order of increasing the electronegativity:
O, AS , P
Q4- Define the following terms:(answer only four)
(a) Nonmetals
(b) Ionic Bond
(c) Molecule
(d) Electron Affinity
(e) Standard Enthalpy of Formation
GOOD LUCK