AP Midterm review: Ch. 3-4, 10-12, 14,15,19 Study solubility rules and be sure you can write net ionic equations. ____

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1. What mass of glucose (mw  180 g/mol) must be dissolved in enough water to produce 1000. mL of 0.45 M glucose solution? a. 99 g b. 81 g c. 400g d. .40 g e. 81.0 g 2. Balance the following equation with the smallest whole number coefficients. What is the coefficient for O2 in the balanced equation? C4H9SO  O2  CO2  SO2  H2O a. 54 b. 29 c. 23 d. 32 e. 27 3. Balance the following equation with the smallest whole number coefficients. What is the coefficient for H2O in the balanced equation? LiBF4  H2O  H3BO3  HF  LiF a. 3 b. 2 c. 5 d. 6 e. 8 4. What mass of phosphoric acid, H3PO4, would actually react with 7.17 grams of LiOH? 3LiOH  H3PO4  Li3PO4  3H2O a. 3.27 g b. 6.53 g c. 9.80 g d. 19.6 g e. 29.4 g 5. If 20.0 g of each reactant were used in performing the following reaction, which would be the limiting reactant? 2MnO2  4KOH  O2  Cl2  2KMnO4  2KCl  2H2O a. MnO2 b. KOH c. O2 d. Cl2 e. KMnO4 6. If 25 grams of methane, CH4, and 30 g of ammonia, NH3, are combined w/ excess oxygen, how much methane or ammonia will be left when the reaction is finished? CH4  NH3  O2  2HCN  6H2O a. 0.10g NH3 b. 0.10 mol CH4 c. 0.10 g CH4 d. 10 g NH3

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e. 0.10 mol NH3 7. The reaction of 5.0 g of CuSO4 with excess sodium hydroxide produced 2.6 g of Cu(OH)2. What percent yield of Cu(OH)2 was obtained? CuSO4  2 NaOH  Cu(OH)2  Na2SO4 a. 52% b. 61% c. 32% d. 85% e. 92% 8. Which element and group are not correctly matched? Element

Periodic Group or Classification

a. Sb metalloid b. Kr noble gas c. Al alkali metal d. F halogen e. Ca alkaline earth metal ____ 9. Which of the following is the BEST definition of a salt? a. A substance that produces ions in solution b. A substance that is completely ionized in solution. c. A compound composed of metals and nonmetals. d. A compound that contains a cation other than H+ and an anion other than OH- or O2e. A substance that does not produce ions in solution. ____ 10. Which one of the following is a weak acid? a. HClO4 b. HCl c. HBr d. HI e. CH3COOH ____ 11. Which one of the following compounds is incorrectly identified as to type of compound? Substance

Type of Compound

a. RbOH strong base b. HClO3 strong acid c. H2S weak acid d. Ca(OH)2 insoluble base e. H3PO2 weak acid ____ 12. Which one of the following salts is insoluble in water? a. NaF b. NH4ClO3 c. CuCl2 d. CaSO4 e. Ba3(AsO4)2 ____ 13. What is the net ionic equation for the following formula unit equation? Cu(NO3)2(aq)  H2S(aq)  CuS(s)  2HNO3(aq) a. Cu2+(aq)  H2S(aq)  CuS(s)  2H+(aq) b. [Cu2+(aq)  2NO3(aq)]  H2S(aq)  CuS(s)  2[H+(aq)  2NO3(aq)]

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c. Cu2+(aq)  2H+(aq)  S2(aq)  CuS(s)  2H+(aq) d. Cu2+(aq)  S2(aq)  CuS(s) e. Cu2+(aq)  2NO3(aq)  2H+(aq)  S2(aq)  CuS(s)  2H+(aq)  2NO3(aq) Determine the oxidation number of the underlined element in K2CO3. a. 1 b. 2 c. 4 d. 4 e. 5 Determine the oxidation number of the underlined element in H2CrO4. a. 1 b. 2 c. 3 d. 4 e. 6 What are the oxidation numbers (oxidation states) of the elements in HCO3? a. H  1, C  5, O  2 b. H  1, C  3, O  2 c. H  1, C  2, O  2 d. H  2, C  2, O  2 e. H  1, C  4, O  2 Which of the following matched pairs of name and formula has an error? Formula

Name

a. Mn2O3 manganese(II) oxide b. FeCl3 ferric chloride c. SnBr2 stannous bromide d. CuS copper(II) sulfide e. CrO chromium(II) oxide ____ 18. What is the reducing agent in the following reaction? 6KOH(aq)  3Cl2(g)  KClO3(aq)  5KCl(aq)  3H2O( ) a. KOH b. Cl2 c. KClO3 d. KCl e. H2O ____ 19. In the following reaction NaClO3 is ____. 5NaClO3(aq)  3H2O( )  3I2(s)  6HIO3(aq)  5NaCl(aq) a. the oxidizing agent and is oxidized. b. the oxidizing agent and is reduced. c. the reducing agent and is oxidized. d. the reducing agent and is reduced. e. neither an oxidizing agent nor a reducing agent. ____ 20. Which of the following reactions is not a decomposition reaction? a. 2HgO(s)  2Hg( )  O2(g) b. H2(g)  Cl2(g)  2HCl(g) c. NH4NO3(s)  N2O(g)  2H2O(g)

d. Mg(OH)2(s)  MgO(s)  H2O(g) e. 2H2O2(aq)  2H2O( )  O2(g) ____ 21. Consider the neutralization of H2SO3 by LiOH. Which of the following is a product? a. lithium sulfite b. dilithium sulfite c. lithium hydroxide d. sulfuric acid e. lithium sulfate ____ 22. The burning of 80.3 g of SiH4 at constant pressure gives off 3790 kJ of heat. Calculate H for this reaction. SiH4(g) + 2O2(g) SiO2(s) + 2H2O( ) a. -1520 kJ/mol rxn b. - 47.2 kJ/mol rxn c. - 4340 kJ/mol rxn d. -2430 kJ/mol rxn e. + 4340 kJ/mol rxn ____ 23. Calculate H0 for the following reaction at 25.0°C. Fe3O4(s) -1118

H

+

CO(g) -110.5

3FeO(s) -272

+

CO2(g) -393.5

a. -263 kJ b. 54 kJ c. 19 kJ d. -50 kJ e. 109 kJ ____ 24. Estimate the enthalpy change for the reaction below from the average bond energies given. There are two Cl-Cl and two C-H bonds in CH2Cl2. Remember that energy is absorbed when bonds are broken and released when they are formed. CH4(g) + 2Cl2(g) CH2Cl2(g) + 2HCl(g)

C-H H-Cl

Average Bond Energies 413 kJ/mol Cl-Cl 432 kJ/mol C-Cl

242 kJ/mol 339 kJ/mol

a. -232 kJ/mol b. +578 kJ/mol c. +232 kJ/mol d. -578 kJ/mol e. +541 kJ/mol ____ 25. Calculate S0 for the reaction below at 25°C. S0 for SiH4 = 204.5 J/mol•K, for O2(g) = 205.0 J/mol•K, for SiO2(s) = 41.84 J/mol•K, for H2O( ) = 69.91 J/mol•K. SiH4(g) + 2O2(g) SiO2(s) + 2H2O( ) a. -353.5 J/K b. -432.8 J/K c. 595.0 J/K d. -677.0 J/K e. -880.3 J/K ____ 26. Which chemical change listed below represents a decrease in entropy? a. N2(g) + 3 H2(g) NH3(g)

b. CaCO3(s) CaO(s) + CO2(g) c. 2 NO2(g) N2(g) + 2 O2(g) d. 2 C6H6( ) + 15 O2(g) 12 CO2(g) + 6 H2O(g) e. 2 NaCl( ) 2 Na( ) + Cl2(g) ____ 27. Consider the conversion of a substance from solid to liquid. Solid

Liquid

At one atmosphere pressure and at the melting point of the substance, ____. a. H = 0 for the process b. S = 0 for the process c. E = 0 for the process d. G = 0 for the process e. both H = 0 and E = 0 for the process ____ 28. Which one of the following statements is not correct? a. When G for a reaction is negative, the reaction is spontaneous. b. When G for a reaction is positive, the reaction is nonspontaneous. c. When G for a reaction is zero, the system is at equilibrium. d. When H for a reaction is negative, the reaction is never spontaneous. e. When H for a reaction is very positive, the reaction is not expected to be spontaneous. ____ 29. For which set of values of H and S will a reaction be spontaneous (product-favored) at all temperatures? a. H = +10 kJ, S = -5 J/K b. H = -10 kJ, S = -5 J/K c. H = -10 kJ, S = +5 J/K d. H = +10 kJ, S = +5 J/K e. no such values exist ____ 30. Determine the rate-law expression for the reaction below. 2A + B2 + C A2B + BC Trial 1 2 3 4

Initial [A] 0.20 M 0.40 M 0.20 M 0.20 M

Initial [B2] 0.20 M 0.30 M 0.30 M 0.40 M

Initial [C] 0.20 M 0.20 M 0.20 M 0.40 M

Initial Rate of Formation of BC 2.4  10-6 M•min-1 9.6  10-6 M•min-1 2.4  10-6 M•min-1 4.8  10-6 M•min-1

a. rate = k[A]2[B2][C] b. rate = k[B2]2[C]2 c. rate = k[A][C]2 d. rate = k[A]2[C] e. rate = k[A][B2][C] ____ 31. Evaluate the specific rate constant at the temperature at which the data were collected. The rate-law expression is rate = k[NO]2[H2]. Experiment 1 2 3

H2(g) + NO(g) N2O(g) + H2O(g) Initial [NO] (M) Initial [H2] (M) Initial Rate (M•s–1) 0.30 0.35 2.835  10–3 0.60 0.35 1.134  10–2 0.60 0.70 2.268  10–2

9.4  10-3 M-2•s-1 2.7  10-2 M-2•s-1 1.6  10-4 M-2•s-1 8.1  10-3 M-2•s-1 9.0  10-2 M-2•s-1 ____ 32. The rate constant for the first order reaction A B + C is k = 3.3  10-2 min-1 at 57 K. What is the half-life for this reaction at 57 K? a. 21 min b. 30 min c. 61 min d. 9.1 min e. 1200 min ____ 33. Which of the following statements concerning graphical methods for determining reaction order is false? a. For a first-order reaction the plot of ln [A] vs. time gives a straight line. b. For a first-order reaction the slope of the straight-line graph equals -ak. c. For a second-order reaction the plot of [A]2 vs. time gives a straight line. d. For a first-order reaction the intercept of the straight-line graph equals ln [A]0. e. For a zero-order reaction the plot of [A] vs. time gives a straight line. ____ 34. A reaction has an activation energy of 40 kJ and an overall energy change of reaction of -100 kJ. In each of the following potential energy diagrams, the horizontal axis is the reaction coordinate and the vertical axis is potential energy in kJ. Which potential energy diagram best describes this reaction? a. c. e. a. b. c. d. e.

b.

d.

____ 35. Given the following potential energy diagram for the one-step reaction X+Y Z+R

The arrow "c" represents the ____.

a. net energy of reaction for the forward reaction b. activation energy for the forward reaction c. net energy of reaction for the reverse reaction d. activation energy for the reverse reaction e. energy content for the reaction ____ 36. Assume the following reaction 3H2 + CO CH4 + H2O occurs by the given reaction mechanism. Step 1 Step 2 Step 3 Overall

H2 H2 H2

+ CO H2CO + H2CO CH4 + O + O H2O 3H2 + CO CH4 + H 2O

slow fast fast

The rate law expression must be rate = ____. a. k[H2]2[CO]2 b. k[H2]2[CO] c. k[H2][CO]2 d. k[H2][CO] e. k[H2]2[CO]3 ____ 37. Which of the following statements about catalysts are false? a. A catalyst lowers the activation energy. b. A catalyst can make a nonspontaneous reaction spontaneous. c. A catalyst speeds up both the forward and reverse reaction. d. A catalyst speeds up the rate of reaction. e. Catalyst are often transition metals and transition metal oxides. ____ 38. When the system A + B C + D is at equilibrium, a. the forward reaction has stopped. b. the reverse reaction has stopped. c. both the forward and the reverse reactions have stopped. d. neither the forward nor the reverse reaction has stopped. e. the sum of the concentrations of A and B must equal the sum of the concentrations of C and D. ____ 39. Consider the following reaction. What would be the equilibrium constant expression? 4Br2(g) + CH4(g) 4HBr(g) + CBr4(g) a. Kc = b. Kc = c. Kc = d. Kc =

e. Kc = ____ 40. In a 1.0-liter container there are, at equilibrium, 0.20 mole of I2, 0.30 mole of H2, and 0.20 mole of HI. What is the value of Kc for the reaction? H2(g) + I2(g) 2HI(g) a. 0.33 b. 0.67 c. 2.7 d. 1.3 e. 1.5 ____ 41. For the system H2(g) + CO2(g) H2O(g) + CO(g) at equilibrium, the removal of some of the H2O(g) would cause (according to LeChatelier's principle) a. more H2(g) to be form. b. more CO2(g) to be form. c. no change in the amounts of products or reactants. d. more CO(g) to be form. e. the amount of CO(g) to remain constant while the amount of H2O(g) increases to the original equilibrium concentration. ____ 42. Which of the numbered responses lists all the following stresses that would shift the equilibrium to the right (favor the forward reaction), and no other stresses? 2NOCl(g) + 75 kJ 2NO(g) + Cl2(g) I. II. III. IV. a. b. c. d. e.

Add more NOCl. Remove some Cl2. Lower the temperature. Add more NO. I and II I, II, and III I and III II and IV II, III, and IV

Completion Complete each statement. 43. Kinetic summary: For each type of reaction, first- and second-order in reactant A, list the following: a)units of k

b)draw the graph of the best linear relationship between time and [A]. Include axes labels and slope of line

c) half-life formula 44. Thermo summary: For each state function, indicate the sign of the term for spontaneity for that variable alone. G H S Spontaneity

Write the formula for G. What are the units of each in standard tables? Problem Show all work. Allow at least 30 minutes for this section. 45. Consider the following rate data for the reaction below at a particular temperature.

Experiment 1 2 3

Initial [A] 0.10 M 0.20 M 0.10 M

A+B Initial [B] 0.10 M 0.20 M 0.20 M

C Initial Rate of Formation of C 4.0  10–4 M/min 3.2  10–3 M/min 1.6  10–3 M/min

a) Write the rate law. ( Be sure to explain /show how you derived it.)

b) What is the value of k? Include the correct units.

c) In a second experiment, a different reaction is found to be second order in reactant A with no other rate contribution from any other reactant. Sketch a graph showing time vs [A]. Label the slope. 46. At a certain temperature Kc = 25 and a reaction vessel contains a mixture with the following concentrations : [H2] = 0.10 M, [Br2] = 0.10 M and [HBr] = 0.48 M. H2(g) + Br2(g)

2HBr(g)

a) Using chemical symbols, write the equilibrium expression for Kc. b) Find Q.

c) At the concentrations given, which direction will reaction shift and what will happen to the concentration of H2? d) If more Br2 is added, in which direction will equilibrium shift? e) What type of reaction is this? 47. Calculate G0 at 298 K for the reaction below.

H S0 (J/mol•K)

P4O10(s) -2984 228.9

+

H2O( ) -285.8

H3PO4(s) -1281

69.91

110.5

a) Write the balanced chemical reaction.

b) Calculate Hrxn. c) Calculate Srxn. d) Calculate G0 at 298 K.

e) Is this reaction sponatneous at 298 K?

Why?

AP Midterm review: Ch. 3-4, 10-12, 14,15,19 Answer Section MULTIPLE CHOICE 1. ANS: B PTS: 1 TOP: Concentrations of Solutions 2. ANS: E PTS: 1 DIF: * Harder Question TOP: Chemical Equations 3. ANS: A PTS: 1 TOP: Chemical Equations 4. ANS: C PTS: 1 TOP: Calculations Based on Chemical Equations 5. ANS: B PTS: 1 TOP: The Limiting Reactant Concept 6. ANS: E PTS: 1 TOP: The Limiting Reactant Concept 7. ANS: D PTS: 1 TOP: Percent Yields from Chemical Reactions 8. ANS: C PTS: 1 TOP: The Periodic Table: Metals, Nonmetals, and Metalloids 9. ANS: D PTS: 1 TOP: Aqueous Solutions--An Introduction 10. ANS: E PTS: 1 TOP: Aqueous Solutions--An Introduction 11. ANS: D PTS: 1 TOP: Aqueous Solutions--An Introduction 12. ANS: E PTS: 1 DIF: * Harder Question TOP: Aqueous Solutions--An Introduction 13. ANS: A PTS: 1 TOP: Reactions in Aqueous Solutions 14. ANS: D PTS: 1 TOP: Oxidation Numbers 15. ANS: E PTS: 1 TOP: Oxidation Numbers 16. ANS: E PTS: 1 TOP: Oxidation Numbers 17. ANS: A PTS: 1 TOP: Naming Binary Compounds 18. ANS: B PTS: 1 DIF: * Harder Question TOP: Oxidation-Reduction Reactions 19. ANS: B PTS: 1 TOP: Oxidation-Reduction Reactions 20. ANS: B PTS: 1 TOP: Decomposition Reactions 21. ANS: A PTS: 1 TOP: Metathesis (Acid--Base) Reactions 22. ANS: A PTS: 1 TOP: Thermochemical Equations 23. ANS: C PTS: 1 TOP: Hess's Law 24. ANS: A PTS: 1 TOP: Bond Energies 25. ANS: B PTS: 1 TOP: Entropy, S, and Entropy Change, delta S 26. ANS: A PTS: 1 TOP: Entropy, S, and Entropy Change, delta S 27. ANS: D PTS: 1 TOP: Free Energy Change, delta G, and Spontaneity 28. ANS: D PTS: 1 TOP: The Temperature Dependence of Spontaneity 29. ANS: C PTS: 1 TOP: The Temperature Dependence of Spontaneity 30. ANS: D PTS: 1 TOP: Concentrations of Reactants: the Rate-Law Expression 31. ANS: E PTS: 1 TOP: Concentrations of Reactants: the Rate-Law Expression 32. ANS: A PTS: 1 TOP: Concentration Versus Time: The Integrated Rate Equation 33. ANS: C PTS: 1 DIF: * Harder Question TOP: Concentration Versus Time: The Integrated Rate Equation 34. ANS: A PTS: 1 TOP: Transition State Theory 35. ANS: D PTS: 1 TOP: Transition State Theory 36. ANS: D PTS: 1 TOP: Reaction Mechanisms and the Rate-Law Expression

37. 38. 39. 40. 41. 42.

ANS: ANS: ANS: ANS: ANS: ANS:

B D C B D A

PTS: PTS: PTS: PTS: PTS: PTS:

1 1 1 1 1 1

TOP: TOP: TOP: TOP: TOP: TOP:

Catalysts Basic Concepts The Equilibrium Constant The Equilibrium Constant Disturbing a System in Equilibrium: Predictions Disturbing a System in Equilibrium: Predictions

COMPLETION 43. ANS: 1st : s

-1

2nd:

M-1s-1

time vs. ln [A] slope = -k

time vs. 1/ [A] slope = k

ln[A] = ln[Ao] - kt

1/[A] = 1/[Ao] + kt

t1/2 = .693/k

t1/2 = 1/[A]k

PTS: 1 44. ANS: spon: G and

G + - at high T - @low T G=

S (+) If signs don’t indicate same, then depends on T.

G (-),

H + + -

S + + -

Spontaneity yes no at high temps at low temps

H-T S

S is in J/mole K--must multiply by 1000 to use in

G eqn.Others are in kJ/mol.

PTS: 1 PROBLEM 45. ANS: k[A][B]2 As [A] increases 2X, so does rate, so 1st order in [B] As [B] increases 2X, rate increases 4X, so 2nd order in[B] b) k[A][B]2 k = 4.0  10-1 M-2•min-1 c) time on axis 1/[A] on y axis slope = -k

PTS: 1 46. ANS: a) Kc = [HBr]2 [H2][Br2] b) Q = .482 / (.10)(.10) = 23.04 23.04 < 25 so Q < Kc c) Reaction shifts right, so more HBr will be produced, [H2] will decrease. d) If more Br2 is added, equilibrium shift right e) synthesis PTS: 1 47. ANS: a) P4O10(s) + 6H2O( ) 4H3PO4(s) b) Hrxn = 4(-1281) - [(6)(-285.8)] -(-2984) = -425.2 kJ/mol c) Srxn = 4(110.5) - [(6)(69.91)] - (228.9) = - 206.36 J/mol K = -0.20636 kJ/mol K d) G0 = H - [T S0(J/mol•K)x(1kJ/1000J)] -425.2 - 298 K (-0.20636) = -363.7 kJ e) spontaneous since G0 is negative. PTS: 1