IB HL Chemistry 1 MIDTERM REVIEW:

Topic 1: Quantitative Chemistry (Stoichiometry)A. Know the MOLE! Moles to grams, moles to molecules, moles to liters (of

a gas…)B. Nomenclature! C. Know how to calculate empirical and molecular formulas.D. Know all there is to know about stoichiometry. Balancing equations,

conversion factors, limiting reactants.E. Solution Stoichiometry. Molarity.

Topic 2, 3:Atomic Structure and PeriodicityA. Know the basic structure of the atom (and the basic history of why we

know these structures)B. Know electron configurationsC. Know how to use mass spectroscopy to identify isotopes and average

atomic mass.D. Know how to name molecules (ionic, covalent, organic…)E. Know the electron configurations and the rules behind themF. Know how the periodic table is set up and the main trends and be able to

explain them. a. Atomic Radiusb. Electronegativityc. Ionization Energy (First, Second, Third…)

G. Also know the exceptions to these trends and the reasons fr them.

Topic 4: BondingA. Know how to distinguish the different types of bonds (ionic, covalent,

polar, metallic, giant covalent)B. Know VSEPR theory. Be able to draw Lewis structures, know bond

angles, be able to accurately draw 3D structures. Be able to determine polarity in a bond and in a molecule.

C. Know the three major intermolecular forces, when they occur and how they interact. Also know they affect physical characteristics.

D. Know the organic naming basics.E. Know the difference in organic bonding (cis, trans, C…)

Topic 5: EnergeticsA. Know the differences in endo and exothermic reactionsB. Understand enthalpy diagramsC. Be able to use and understand the heat transfer equationD. Understand Hess’ Law

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E. Know how to calculate Enthalpy change using standard enthalpy of formation values.

Topic 6: KineticsA. Understand the concepts of the collision theory and what affects the rate

of the reaction.B. Be able to write rate laws from balanced reactions.

Topic 7: EquilibriumA. Be able to write equilibrium expressions and solve for KcB. Understand Le Chatelier’s principle and how to shift equilibrium

ALL YOUR LABS ARE FAIR GAME!!! Review all lab calculations and concepts!

_____1. What happens when an alkali metal reacts with water?

A. The metal reacts vigorously to produce H2 (g) and an acidic solution.B. The metal reacts vigorously to produce NO2 (g) and an alkaline (basic) solution.C. The metal reacts vigorously to produce H2 (g) and an alkaline (basic) solution.D. The metal reacts vigorously to form O2 (g) and an alkaline (basic) solution.

_____2. Which element’s atoms, in the ground state, will have the largest number of unpaired electrons?A. Si B. P C. S D. Cl

_____3. All isotopes of tin have the sameI number of protons II number of neutrons III mass number

A. I only B. II only C. III only D. I and III only

_____4. Which electron transition in a hydrogen atom releases the most energy?

A. n = 2 to n = 1 C. n = 1 to n = 3 B. n = 5 to n = 4 D. n = 7 to n = 6

_____5. Which of these elements do you predict would be the most electronegative?

A. Li B. Na C. O D. Mg

_____6. If chlorine gas reacts with magnesium metal, the product formed would most likely be

A. MgCl B. Mg2Cl C. MgCl2 D. Mg2Cl2

_____7. Magnesium (relative atomic mass A = 24.30) consists of three isotopes:

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magnesium-24, magnesium-25, and magnesium-26. Based on this information, which statement about magnesium is true?

A. Magnesium-26 is probably the most abundant of the three isotopes found in nature.B. The three isotopes of magnesium are equally abundant.C. Magnesium-24 is probably more abundant than the other two isotopes.D. The isotopes have 24, 25 and 26 neutrons, respectively

_____8. Which one of the following series is arranged in order of increasing value?

A. the reactivities of the halogens: fluorine, chlorine, bromine and iodineB. the radii of : H- ion, H atom, H+ ionC. the electronegativities of: chlorine, bromine, iodineD. first ionisation energies of alkali metals: potassium (K), sodium (Na) , lithium (Li)

_____9. A certain atom has an atomic number Z = 15 and a mass number A = 31. How many electrons will it have in its valence “shell”?

A. one B. two C. three D. five

_____10. On going across a period of the Periodic Table, the elements tend to become less metallic in character. Which one of the following is not an indication of this trend?

A. There is an overall increase in atomic massB. There is an increase in electronegativityC. There is a change in bond type from ionic to covalentD. There is an overall increase in ionisation energy

_____11. Which of the following is the correct electron configuration of the iron (II) ion?

A. [Ar] 4s23d3 C. [Ar] 3d6

B. [Ar] 4s23d5 D. [Ar] 4s13d5

_____12. Given the following five pairs of ions and atoms:

(I) K+ and Ca2+ (II) F- and Cl- (III) Ar and S2- (IV) Fe2+ and Fe3+

Which of the pairs are iso-electronic?

A. all of them B. I and III C. I and IV D. I and II

_____13. Which of the following atoms/ions would have the smallest radius?A. K+ B. Ca2+ C. Ar D. Cl-

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_____14. Which of the following compounds has the greatest empirical formula mass?

A. C6H6 C. C3H6 B. C4H10 D. C2H6

____15. The relative molar mass (g mol-1) of iron (III) sulfate, Fe2(SO4)3 is approximately

A. 192 B. 208 C. 344 D. 400

_____16. Which one of the following is not the same as the rest?

A. The number of molecules in 4 moles of CO2

B. The number of hydrogen atoms in 2 moles of H2OC. The number of chloride ions in 4 moles of CaCl2

D. The number of hydrogen atoms in 1/2 mole of C3H8

_____17. Chlorofluorocarbons are harmful pollutants because they reduce the ozone layer in the upper atmosphere. Freon (CF2Cl2) is one such compound. What mass percent of fluorine does it contain?

A. 15.7 % B. 28.6 % C. 38.0 % D. 31.4 %

_____18. A sample of methane (CH4) has a mass of 48.0 grams. How many hydrogen atoms does this sample contain?

A. 12 B. 7.22 x 1024 C. 2.41 x 1024 D. 1.81 x 1024

CaCO3 (s) CaO (s) + CO2 (g)

_____19. When heated, CaCO3 (M = 100 g mol-1) decomposes according to the above equation. When 20 g of impure CaCO3 was heated, 0.15 moles of CO2 were obtained. What was the percentage purity of the CaCO3? (Assume none of the impurities produce CO2 upon heating).

A. 15 % B. 25 % C. 55 % 75 %

_____20. The compound called chloroethene (C2H3Cl ) can be burned in oxygen as shown in this equation:

v C2H3Cl (g) + w O2 (g) x CO2 (g) + y H2O (g) + z HCl (g)

In this equation, if the coefficient v = 2, what is the value of the coefficient w?

A. 2 B. 4 C. 5 D. 6

_____21. Suppose equal masses of oxygen gas and hydrogen gas are reacted in a closed container to form water. After the reaction is complete, the container will contain

A. water and oxygen onlyB. water and hydrogen only

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C. water onlyD. water, hydrogen and oxygen

_____22. 1.0 g samples of each of the following hydrate compounds were dehydrated by heating. Which sample would lose the greatest mass percentage due to the removal of water?

Molar Mass, g mol-1

A. MgCl2 * 6 H2O 203B. Mg(NO3)2 * 6 H2O 256 C. NiSO4 * 6 H2O 263D. Fe(NO3)3 * 6 H2O 305

_____23. Caffeine is C8H10N4O2 (molar mass 194 g mol-1). If the average cup of coffee is 250 mL and contains 325 mg of caffeine, what is the molarity of caffeine in coffee?

A. 0.0067 M B. 0.419 M C. 6.70 x 10-6 M D. 2.39 M

_____24. The compound NH4V3O8 may be prepared by the following sequence of reactions:

2 NH3 (g) + V2O5 (s) + H2O 2 NH4VO3 (aq) 3 NH4VO3 (aq) + 2 HCl (aq) NH4V3O8 (aq) + 2 NH4Cl (aq) + H2O

If you start with 1/2 mole of NH3 and all the other reactants are provided in excess, what is the maximum yield of NH4V3O8 which can be obtained?

A. 1/2 mole B. 1/3 mole C. 1/6 mole D. 1/9 mole

_____25. An unknown element Z combines with oxygen to form the compound ZO2. If 48 g of element Z combines with 32 g of oxygen in this reaction, the element Z is most likely

A. carbon (C) B. sulfur (S) C. titanium (Ti) D. tin (Sn)

_____26. A common pigment used is a compound of titanium and oxygen that contains 59.9 % Ti by mass. What is the empirical formula of this compound.

A. TiO B. Ti2O C. TiO2 D. TiO4

Write correct chemical formulas (1 points each)

27. potassium hydroxide _______________ 28. barium carbonate ____________

29. iron (II) oxide _______________ 30. magnesium sulfide ____________

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______ 31. An element called X forms a covalently-bonded compound with hydrogen that has the formula XH3. In which group of the Periodic Table would you expect to find element X?

A. Group 16 (the oxygen family) C. Group 15 (the nitrogen family)B. Group 2 (alkaline earth metals) D. Group 17 (halogens)

_____32. Based on electronegativity trends, which of these covalent bonds is the most polar?

A. B---C B. C---O C. N---O D. O---F

_____33. Which one of these compounds contains bonds that would be primarily ionic?

A. magnesium bromide, MgBr2 C. acetic acid, CH3COOHB. dichloromethane, CH2Cl2 D. silicon tetrachloride, SiCl4

_____34. Carbon, hydrogen and chlorine can combine in different ways to form a series of compounds shown below:

I II III IV CH3Cl CH2Cl2 CHCl3 CCl4

Which of these compounds will be polar molecules?

A. I only B. III onlyC. I and III only F. I, II and III

_____35. Consider the three ions shown here (I - III). Which of them is/are planar; (i.e., flat, having all the atoms in the same plane)?

I. CO32- II. NO3

- III. SO32-

A. I only C. I and II onlyB. II only D. II and III only

_____ 36. Delocalization of electrons, shown by resonance structures, occurs in the bonding of

A. CO2 B. SO2 C. COH2 D. MgO

_____37. Which pair of compounds would have the most similar Lewis electron dot structures and the most similar molecular shapes?

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A. BH3 and NH3 C. CO2 and SO2 B. CH4 and CCl4 D. HCl and H2O

_____ 38. Based on VSEPR theory, the shape of the ClF3 molecule is best described as

A. T-shaped planar C. triangular pyramidB. triangular planar D. tetrahedral

_____39. Which substance is most soluble in water (in mol dm-3) at room temperature?

A. CH3CH3 C. CH3CH2OH B. CH3-O-CH3 D. CH3CH2CH2CH2OH

_____40. Consider the following information about the hypothetical reaction A + B C potential energy of the reactants = 150 kJ potential energy of the products = 75 kJ activation energy = 25 kJ

Which one of these statements IS TRUE about this reaction?

A. The reaction is endothermic, with H = +75 kJB. The reaction is exothermic, with H = -75 kJC. The reaction is endothermic, with H = +50 kJD. The reaction is exothermic, with H = -50 kJ

_____41. Considering the enthalpy diagram shown here,what can be deduced about the relative stabilityof the reactants and products and the sign of H?

A. Products more stable -

B. Products more stable +

C. Reactants more stable -

D. Reactants more stable +

_____42. Suppose a 10 g sample of copper absorbed 200 J of energy. The specific heat capacity of copper is 0.3845 J g-1 oC-1. If the initial temperature of the copper was 25 oC, what was its final temperature?

A. 52 oC B. 45 oC C. 77 oC D. 115 oC

_____43. Equal masses of substance A and substance B are at the same temperature initially. After the two materials absorb equal amounts of heat, the temperature of A is found to be greater than the temperature of B. What can you deduce about their specific heat capacities (Cp)?

A. Cp A = Cp B C. Cp A > Cp BB. Cp A < Cp B D. Cp A is same value as Cp B but opposite sign

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____44. Which one of the following processes is endothermic?

A. NH3 (g) + HCl (g) NH4Cl (s) B. H2O (g) H2O (l)C. CH4 (g) + 2 O2 (g) CO2 (g) + 2 H2O (g)D. H2O (s) H2O (l)

_____45. The enthalpy change for the combustion of ethanol (C2H5OH) is -1370 kJ mol-1. How much heat is released when 11.5 g of ethanol undergoes complete combustion?

A. -1370 kJ B. - 343 kJ C. - 5480 kJ D. - 686 kJ

_____46. The reaction of magnesium metal with aqueous silver nitrate (shown below) is exothermic.

Mg (s) + 2 AgNO3 (aq) 2 Ag (s) + Mg(NO3)2 (aq)

Which of these experiments would exhibit the greatest temperature increase?

A. 0.24 g of Mg are added to 100 cm3 of 0.10 M AgNO3 B. 0.48 g of Mg are added to 100 cm3 of 0.20 M AgNO3 C. 0.48 g of Mg are added to 100 cm3 of 0.40 M AgNO3 D. 0.96 g of Mg are added to 100 cm3 of 0.20 M AgNO3

_____47. A student wanted to determine the enthalpy change H for the reaction

2 NaHCO3 (s) Na2CO3 (s) + CO2 (g) + H2O (l) H = ?

Because this reaction is difficult to carry out directly, the student decided that she could easily perform the two reactions shown below, and by measuring their H values, calculate the desired H value.

(1) NaHCO3 (s) + HCl (aq) CO2 (g) + H2O (l) + NaCl (aq) H1

(2) Na2CO3 (s) + 2 HCl (aq) CO2 (g) + H2O (l) + 2 NaCl (aq) H2

Which expression below should the student use to calculate the desired H value?

A. H = 2 H1 + H2 C. H = 2 H1 - H2

B. H = H2 - 2 H1 D. H = 2 H2 + H1

_____48. Which one of these equations represents the standard enthalpy of formation for ethanol, C2H5OH?

A. 2 CH4 (g) + H2O (g) C2H5OH (l)B. 2 CO2 (g) + 3 H2O C2H5OH (l) + 3 O2 (g)C. 2 C (s) + 3 H2 (g) + 1/2 O2 (g) C2H5OH (l)D. 2 C (s) + 3 H2O (l) C2H5OH (l)

_____49. Burning sulfur in excess oxygen produces the pollutant gas sulfur dioxide, SO2:

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S (s) + O2 (g) SO2 (g)

When 8 g of sulfur are burned, 80 kJ of heat are evolved. What is the standard enthalpy of formation of sulfur dioxide?

A. - 80 kJ B. - 320 kJ C. + 80 kJ D. + 320 kJ

1. This question refers to the modern theory of the atom. 75.5 %

A mass spectrometer is used to determine the atomic massesof the naturally-occurring isotopes of a certain element.. 24.4 % The resulting mass spectrum is shown here.

mass 35 36 37

a. (6 Pts) Based upon this data, calculate the average atomic mass of this element. Then write isotope symbols for each of its isotopes, and state the number of protons, electrons, and neutrons in each.

b. (10 Pts) Explain how the mass spectrometer is able to separate and identify these two individual isotopes by naming and describing the key operating parts of the instrument. A sketch may by included as part of your answer.

c. (2 Pts) Write the full electron configuration and the shorthand electron configuration of the element whose mass spectrum is shown in the graph above. .

d. (7 Pts) When a tube containing a sample of this element is electrically heated and viewed through a spectroscope, a number of distinct bright lines are seen. Discuss how and why this pattern occurs.

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2. This question refers to the Periodic Table and trends among the elements.

a. (6 Pts) Define the terms: ionisation energy and electronegativity

b. For each of the following properties, state how you would expect it to change in the direction indicated. Also give reasons for the change, based upon your knowledge of the structure of the atom.

(6 Pts) The atomic radius going across a Period.

(6 Pts) The radius of an anion compared to its parent atom

(6 Pts) The first ionisation energy going down a group

c. (6 Pts) Sketch a graph of ionisation energy showing the first four ionisations of the element aluminum. Explain the general shape and spacing of your graph and its data points.

d. (5 Pts) Ionisation energies generally increase as you go across a Period. However, the first ionisation energy of the element beryllium (Be) is about 900 J mol-1 while that of the next element boron (B) is only about 700 kJ mol-1. Explain why this apparent contradiction occurs.

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3. Write balanced chemical equations showing each of these reactions. Use appropriate symbols to indicate the state of matter (solid, liquid or gaseous)

c. Aqueous barium nitrate reacts with aqueous sodium phosphate to produce a precipitate of barium phosphate and aqueous sodium nitrate.

4. "Mustard gas" is a chemical warfare agent that was used by many nations (including the U.S.) during World War I. It is easy to manufacture, which makes it an attractive "weapon of mass destruction" for terrorists.

a. Mustard gas consists of 30.19% carbon, 5.03% hydrogen, 44.65% chlorine, and 20.19% sulfur. Calculate the empirical formula for this substance.

5. (15 Pts) This problem refers to the production of aluminum metal from an ore called bauxite. Bauxite consists mostly of Al2O3 , which reacts with carbon at high temperatures. The process uses large amounts of electric power; that’s why it makes sense to recycle aluminum cans. The balanced equation for the reaction is

Al2O3 (s) + 3 C (s) 2 Al (l) + 3 CO (g)

Suppose you react 25.0 grams of Al2O3 with 15.0 grams of carbon.

a. Determine which reagent is limiting and which is excess.

b. What is the theoretical yield (grams) of aluminum metal that can be formed?

c. What mass of the excess reactant will be left over?

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6. a. Explain how you would prepare 250 mL of an aqueous solution of MgCl2 that has a concentration of 0.150 mol dm-3. Include any necessary calculations, and describe how you would perform this in the lab (including any necessary glassware that you need).

b. What are the concentrations of magnesium ions and chloride ions in this solution?

c. Suppose the above solution is now mixed with 500. mL of a second MgCl2 solution having a concentration of 0.300 mol dm-3. Calculate the concentration of the final solution.

7a. Propanol (C3H7OH) is very soluble in water but 1-octanol (C8H17OH) is not. Fully explain the solubility behavior of each alcohol, and why they differ.

b. The molecule BF3 has a triangular planar shape while the NF3 molecule is a triangular pyramid. Explain why this difference occurs.

c. Draw a sketch that represents the correct geometry of the BrF5 molecule. State the shape and the bond angles.

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8. There are many different alkanes that have six carbons. Draw condensed structural formulas showing all possible structural isomers for the 6-carbon alkanes, and name each compound.

(It would help me grade this if you draw boxes around each isomer with its name).

9. It is the year 2009. You have graduated from college with a degree in chemical engineering, and are making lots of money! You are a member of a project team that is trying to design a better automobile. One of the problems is to select what fuel would be best to use in this future car. Two fuels are under consideration -- propane gas (C3H8) and liquid methanol (CH3OH).

Compare the fuel value of these two fuels. Fuel value is defined as how many kilojoules of energy are released per gram of fuel burned. Use this definition, along with the data below, to determine which of these two fuels has the highest fuel value. Support your answer with balanced equations and any necessary calculations.

C3H8 (g) CH3OH (l) CO2 (g) H2O (l)Ho

f (kJ/mole): -104 -239 -394 -286

10. A student team has been given the following research question:

“Determine the H for the reaction of magnesium metal with hydrochloric acid.” The balanced equation is Mg (s) + 2 HCl (aq) H2 (g) + MgCl2 (aq)

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The students decide to do the reaction in a “coffee cup” calorimeter. They measure out some hydrochloric acid into the coffee cup, and then drop in a piece of magnesium. The reaction starts to“fizz” vigorously, and the temperature rises quickly. The students record the initial and the final temperature. When the reaction is over, the magnesium is gone and a clear solution remains.

mass of magnesium reacted 2.43 gvolume of HCl used 100 mL concentration of HCl used 3.0 Mmass of final solution in coffee cup 103 ginitial temperature of reaction 23.5 oCpeak temperature of reaction 54.0 oC specific heat (Cp) of aqueous HCl 4.20 J / g oC

11. Calculate how much heat was given off in this reaction, using the heat transfer equation.

b. Which reactant was the limiting reactant, Mg or HCl? (Show calculations)

c. What is the H value for the reaction? (Show calculations)

d. Discuss the most likely sources of error in this experiment, and which would be the most significant and why.

12. a. Write the equation that shows the formation of acetylene gas, C2H2, from its elements.

b. Using the following reaction data, calculate the standard enthalpy of formation Hof for acetylene

gas.

(1) C2H2 (g) + 5/2 O2 (g) 2 CO2 (g) + H2O (l) H = -1300 kJ

(2) C (s) + O2 (g) CO2 (g) H = - 394 kJ

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(3) H2 (g) + 1/2 O2 (g) H2O (l) H = -286

13. (8 Pts) We understand reaction rates in terms of the "collision theory." What does this theory say?

b. (8 Pts) State the effect of concentration on the rate of a reaction in solution, and explain in terms of the collision theory why this effect occurs.

c. (8 Pts) State the effect of a catalyst on the rate of a reaction, and explain how a catalyst achieves this effect. Again, draw and label an appropriate Boltzmann-type curve to support your explanation.

d. (7 Pts) For a gas-phase reaction, state one additional variable, other than temperature and catalyst, that would affect the reaction rate, and explain in terms of the collision theory why this effect occurs.

14. (6 Pts) Given the reaction 2 NH3 (g) N2 (g) + 3 H2 (g) If the initial rate of formation of nitrogen gas is 0.25 mol dm-3 min-1

a. What is the rate of formation of hydrogen gas? _______________b. What is the rate by which NH3 (g) decreases? ________________c. Write an equilibrium expression for the above reaction.

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