Which of the Following Statements Regarding the Reaction Shown Above Is NOT True?

AP Chemistry Midterm Review

1. Cr2O72− + 6 I − + 14 H + → 2 Cr3+ (aq) + 3 I2 + 7H2O

Which of the following statements regarding the reaction shown above is NOT true?

(A) The oxidation number of chromium changes from +6 to +3.

(B) The oxidation number of iodine changes from – 1 to 0 .

(D) The oxidation number of oxygen remains the same.

(E) Iodine is oxidized and chromium is reduced.

2. CaCO3(s) → CaO (s) + CO2(g)

A sample of pure CaCO3 was heated and decomposed according to the reaction given above. If 28 grams of

CaO were produced by the reaction, what was the initial mass of CaCO3?

(A) 14 grams

(B) 25 grams

(D) 50 grams

(E) 84 grams

3. ___CuFeS2 + ___O2 → ___Cu2S + ___FeO + ___SO2

When the reaction above is balanced, what is the coefficient for O2 if all the coefficients are reduced to the

lowest whole number.

(A) 2

(B) 3

(D) 6

(E) 8

4. A student added 1 liter of a 1.0 M KCl solution to 1 liter of a 1.0 M Pb(NO3)2 solution. A lead chloride

precipitate formed and nearly all of the lead ions disappeared from the solution. Which of the following lists

the ions remaining in solution in order of decreasing concentration?

(A) NO3− > K+ > Pb2+

(B) NO3− > Pb2+ > K+

(D) K+ > NO3− > Pb2+

(E) Pb2+ > NO3− > K+

5. 2 MnO4 – + 5 SO32 – + 6 H+ → 2 Mn2+ + 5 SO42 – + 3 H2O

Which of the following statements is true regarding the reaction given above?

(A) MnO4− acts has been oxidized

(B) H+ acts as the oxidizing agent

(D) SO32− acts as the reducing agent

(E) MnO4− acts as the reducing agent

6. Which one of the following has its name and chemical formula correctly matched?

(A) HIO3 hydroiodic acid

(B) HIO hypoiodous acid

(D) NaIO3 sodium iodide

(E) CuIO2 cupric iodate

7. An ion containing only oxygen and chlorine is 31% oxygen by mass. What is its empirical formula?

(A) ClO ─

(B) ClO2 ─

(D) ClO4 ─

(E) ClO5 ─

8. Ethylene glycol, the major ingredient in antifreeze, freezes at ─11.5oC. What is the freezing point in Kelvin?

(A) – 261.7

(B) ─11.5

(D) 0

(E) 261.7 K

11. Which of the following has 3 significant figures?

I. 1990 m

II. 0.02 m

III. 0.0560 m

IV. 1.70 x 102 m

(A) I only

(B) I, II, and IV

(D) I, III, and IV

(E) none of the above

12. Which of the following regarding atomic theory is NOT true?

(A) Dalton was the first person to suggest the existence of atoms.

(B) Rutherford's experiments with alpha particle scattering led to the conclusion that positive

charge was concentrated in an atom's nucleus.

(D) Millikan's oil drop experiment led to the calculation of the charge on an electron.

(E) Thomson's cathode ray experiments confirmed the existence of the electron.

13. Elements in group 7A on the periodic table are known as the

(A) halogens

(B) alkali metals

(D) iron family

(E) noble gases

14. The correct name for HClO4 is

(A) hydrochloric acid

(B) hypochloric acid

(D) chloric acid

(E) hydrogen chlorate

16. Water and a salt are always the products of a(n) ___ reaction.

(A) redox

(B) displacement

(D) neutralization

(E) metathesis

17. What is/are the spectator ion(s) in the reaction between Pb (s) and HCl(aq)?

(A) Cl─ and H+

(B) H+ and Pb2+

(D) H+ only

(E) there are no spectator ions

18. Which of the following compounds is 100% dissociated in aqueous solution?

(A) Mg(OH)2

(B) Sc2S3

(D) BaSO4

(E) HNO3

19. In which of the following compounds has a percent composition of 30% N and 70 % O?

(A) N2O5

(B) NO

(D) N2O

(E) NO2

20. The following data were gathered in an experiment to determine the density of a sample of an unknown

substance.

Mass of the sample 7.5 grams

Volume of the sample 2.5 mL

The density of the sample should be reported as

(A) 3 g/ cm3

(B) 3.0 g/ cm3

(D) 0.3 g/ cm3

(E) 0.33 g/ cm3

21. Which of the following unbalanced equations would have the net ionic equation of

H+ + OH – → H2O? (Do not worry about balancing.)

I. HNO3(aq) + KOH (aq) →

II. Fe(s) + Ni(NO3)2(aq) →

III. HCl (aq) + Na2S (aq) →

IV. Mg(s) + HCl(aq) →

(A) I, II, III, and IV

(B) III only

(D) IV only

(E) I only

22. The name of the following compound, C2H6, is

(A) ethane

(B) tetrane

(D) propane

(E) pentane

23. NaCH3COO Ba(NO3)2 KCl

Aqueous solutions of equal concentration of the three compounds listed above are prepared in 3 separate

containers. A precipitate in one of the containers could be expected when a solution of ___ is added.

(A) SO42─ ions

(B) Cu2+ ions

(D) nitric acid

(E) potassium chlorate

24. Use the following reactions to determine the activity series for the halogens. Do not look at the periodic

table until AFTER you have tried this.

Br2(aq) + 2 NaI(aq) → 2 NaBr (aq) + I2(aq)

Cl2(aq) + 2 NaBr(aq) → 2 NaCl(aq) + Br2(aq)

(A) Br < Cl I

(B) I Br < Cl

(D) I < Cl < Br

(E) Cl < I < Br

25. On the periodic table, which group typically has an oxidation number of ─2 ?

(A) 5A

(B) 6A

(D) 3A

(E) 2A

26. Which of the following best represents the net ionic equation for the reaction of solid sodium carbonate

with an aqueous solution of magnesium chloride solution?

(A) Na2CO3 + MgCl2 → MgCO3 + 2 NaCl

(B) Na2CO3 + Mg2+ → MgCO3 + 2 Na+

(D) 2 Na+ + 2 Cl– → 2 NaCl

(E) There is NO net-ionic equation b/c everything is soluble!

27. When 80.0 mL of a 0.40 M NaI solution is combined with 20.0 mL of a 0.30 M CaI2 solution, what will be

the molar concentration of I− ions in the solution?

(A) 0.70 M

(B) 0.44 M

(D) 0.35 M

(E) 0.10 M

28. A beaker contains 150.0 mL of a 0.20 M Pb(NO3)2 solution. If 50.0 mL of a 0.20 M solution of MgCl2 is

added to the beaker, what will be the final concentration of Pb2+ ions in the solution?

(A) 0.20 M

(B) 0.10 M

(D) 0.025 M

(E) 0.012 M

29. How much 0.1-molar NaOH solution must be added to 100 milliliters of a 0.2-molar H2SO4 solution in

order to neutralize all of the hydrogen ions in H2SO4

(A) 100 mL

(b) 200 mL

(D) 400 mL

(E) 500 mL

30. How much water must be added to a 50.0 mL solution of 0.60 M HNO3 to produce a 0.40 M solution of

HNO3?

(A) 25 mL

(B) 33 mL

(D) 67 mL

(E) 78 mL

5. Which of the following statements best describes the effect of temperature on reaction rates?

A) In general, reaction rates increase with increasing temperature.

B) In general, reaction rates decrease with increasing temperature.

C) Only rates of reactions involving molecules with low-energy bonds are dependent on temperature.

D) Rates of reactions involving catalysts are not dependent on temperature.

E) The effect of temperature on a reaction rate is always unpredictable.

Step 1: (CH3)3CBr (aq) → (CH3)3C+ (aq) + Br – (aq)

Step 2: (CH3)3C+ (aq) + H2O (l) → (CH3)3 COH2+ (aq)

Step 3: (CH3)3COH2+ (aq) → H+ (aq) + (CH3)3COH (aq)

8. The above represents a proposed mechanism for the hydrolysis of (CH3)3CBr. What are the overall products

of the reaction?

A) (CH3)3C+ and Br –

B) (CH3)3 COH2+ and H+

C) (CH3)3COH and H+

D) (CH3)3COH, H+, and Br –

E) H+ and Br –

9. At a pressure of 1 atm, water boils at 100oC. How would an increase in pressure affect the temperature at

which water boils?

A) The water will boil at a higher temperature.

B) The water will boil at a lower temperature.

C) The boiling point of water is independent of pressure.

D) The boiling point of water is only dependent on pressure at the triple point.

E) The boiling point of water is only dependent on pressure at the critical point.

Questions 11 refers to the following graph

11. Which reaction(s) is/ are exothermic?

A) I

B) II

C) III

D) I and II

E) II and III

13. Appropriate uses of a visible-light spectrophotometer include which of the following?

I. Determining the concentration of a solution of Cu(NO3)2.

II. Measuring the conductivity of a solution of KMnO4.

III. Determining which ions are present in a solution that may contain Na+, Mg2+, Al3+

A) I only

B) II only

C) III only

D) I and II

E) I and III

14. Which of the following solutions has the lowest freezing point?

A) 0.10 m ZnSO4

B) 0.10 m CoI2

C) 0.10 m C6H12O6, glucose

D) 0.10 m NaI

E) 0.10 m AlI3

C2H2 (g) + H2O (g) CH3CHO (g) exothermic

15. An equilibrium mixture of the reactants is placed in a sealed container at 150oC. The amount of the

product may be increased by which of the following changes?

I. adding 1 mole of Ar(g) to the container

II. decreasing the volume of the container

III. raising the temperature of the container

A) I only

B) II and III

C) III only

D) I and II

E) II only

16. A first-order process has a half-life of 6930 years at. How much time is needed for an initial concentration

of 0.025 M to drop to 0.015 M? (Assume the temperature remains constant.)

A) – 1.00 x 10 4 years

B) 5109 years

C) 7.89 x 10– 4 years

D) 152 minutes

E) 190 minutes

2 NO (g) + O2 (g) → 2 NO2 (g)

18. Which two of the following possible intermediate mechanisms would support this reaction?

I. 2 NO (g) → N2O2 (g)

II. NO (g) + O2 (g) → NO3 (g)

III. 2 NO2 (g) → N2O2 (g) + O2 (g)

IV. NO3 (g) + NO (g) → 2 NO2 (g)

A) I and II

B) II and III

C) III and IV

D) II and IV

E) I and IV

20. Given the potential energy profile for a reaction shown above, which letter corresponds to Ea for the

forward reaction (Reactant →Product)?

A) A

B) B

C) C

D) D

E) E

21. Which of the following is a true statement about catalysts?

A) A catalyst will change the equilibrium constant for a reaction

23. The plot of ln[A] versus time gives a straight line, this implies the rate law is

A) rate = k[A]2

B) rate = k[A] – 2

C) rate = k[A]0

D) rate = k[A]– 1

E) rate = k[A]

B) A catalyst will decrase the rate of a reaction.

C) A catalyst will always provide a simpler mechanism for the reaction.

D) A catalyst will always lower the activation energy for a reaction.

E) A catalyst will change the ΔG for the reaction.

30. How many moles of solid Ca(NO3)2 should be added to 450 mL of 0.35 M Al(NO3)3 to increase the

concentration of the nitrate ion to 1.7 M? (Assume that the volume of the solution remains constant.)

A) 0.07 mole

B) 0.15 mole

C) 0.29 mole

D) 0.45 mole

E) 0.77 mole

3 H2 (g) + N2 (g) 2 NH3 (g)

31. If 2.00 mol H2, 1.00 mol N2, and 2.00 mol NH3 are placed into a 1.00-L evacuated flask, how will the

reaction above proceed if Kc = 0.105 at this temperature.

A) The reaction must proceed form right to left.

B) The reaction must proceed from left to right.

C) The reaction is already at equilibrium, so no net movement will occur.

D) The reaction cannot establish equilibrium at this temperature.

E) The reaction will proceed from left to right until 2.23 mol NH3 have been produced.

32. If 20. mL of a 0.10 M silver nitrate solution is added to 80. mL of a 0.10 M calcium chloride solution, what

is the final concentration of chlorine ion?

A) 0.08 M

B) 0.10 M

C) 0.14 M

D) 0.16 M

E) 0.18 M

N2 (g) + 3 H2 (g) 2 NH3 (g) + heat

33. For the reaction above, which of the following statements are true regarding an equilibrated mixture?

I. Increasing the pressure with helium shifts the equilibrium towards products.

II. Cooling the mixture shifts the reaction towards products.

III. Adding a catalyst shifts the equilibrium towards products.

A) I

B) II

C) III

D) I and III

E) I, II, and III

H2 (g) + I2 (g) → 2 HI (g)

34. For the above reaction, the rate law is Rate = k[H2][I2]. If a small amount of iodine vapor (I2) is added to a

reaction mixture that was 0.10 molar in H2 and 0.20 molar in I2, which of the following statements is true?

A) Both k and the reaction rate decrease

B) Both k and the reaction rate increase

C) Both k and the reaction rate remain the same

D) Only k increases, the reaction rate remains the same.

E) Only the rate increases, k remains the same.