Unit 8 Progress Check: MCQ - SUPERTALLTEACHER

AP Chemistry

Unit 8 Progress Check: MCQ

Scoring Guide

1. Pure water autoionizes as shown in the equation above. Based on this information, which of the following is correct?

The autoionization equilibrium for pure water favors the formation of reactants at

A

.

compared to

The autoionization equilibrium for pure water produces the same amount of

ions at

and

B

.

C At

,

for pure water.

D At

,

for pure water.

2.

at

Based on the information above, which of the following is true for a sample of pure water at

?

A

B

C

D

3.

The endothermic autoionization of pure water is represented by the chemical equation shown

above. The of pure water is measured to be 7.00 at

and 6.02 at

. Which of the

following statements best explains these observations?

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AP Chemistry

Unit 8 Progress Check: MCQ

A At the higher temperature water dissociates less, B At the higher temperature water dissociates less, C At the higher temperature water dissociates more, D At the higher temperature water dissociates more,

Scoring Guide

, and the water becomes basic. , and the water remains neutral. , and the water becomes acidic. , and the water remains neutral.

4. Which of the following gives the best estimate for the of a ?

A

because

is a strong acid.

B

because

is a weak acid.

C

because

is a weak base.

D

because

is a strong base.

solution at

5. Which of the following gives the best estimate for the of a ?

solution at

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AP Chemistry

Unit 8 Progress Check: MCQ

A

because

is a strong acid.

B

because

is a strong acid.

C

because

is a strong base.

D

because

is a strong base.

Scoring Guide

6. Which of the following is the correct mathematical relationship to use to calculate the of a aqueous solution?

A

B

C

D

7.

at

Initial

Percent Ionization

Equilibrium

0.150

3.4%

0.100

4.2%

0.0500

5.8%

The equilibrium for the acid ionization of

is represented by the equation above and the

table gives the percent ionization for

at different initial concentrations of the weak acid at

. Based on the information, which of the following is true for a

aqueous solution of

?

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AP Chemistry

Unit 8 Progress Check: MCQ

It has a larger percent ionization, a lower

A

solution does. It has a larger percent ionization, a lower

B

solution does. It has a lower percent ionization, a larger

C

solution does. It has a lower percent ionization, a larger

D

solution.

, and a lower than a

, and a higher

than a

, and a higher

than a

, and a higher than a

Scoring Guide

8.

The reaction between

and water is represented above. A solution that is initially

in

has a of 11.28. Which of the following correctly predicts the of a solution for which

, and why?

The will be lower than 11.28 because decreasing the initial concentration of

A

equilibrium concentration of the conjugate acid

.

increases the

The will be lower than 11.28 because the equilibrium concentration of

B

when the initial concentration of the base decreases.

ions decreases

The will be higher than 11.28 because decreasing the initial concentration of

C

the equilibrium concentration of the conjugate acid

.

decreases

The will be higher than 11.28 because the equilibrium concentration of

D

when the initial concentration of the base decreases.

ions increases

9.

The acid ionization equilibrium for

at

is shown above. A

aqueous solution of

this acid has a of about 4.2. If a solution with an initial concentration of

of

is

allowed to reach equilibrium at the same temperature, which of the following correctly predicts its

, and why?

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AP Chemistry

Scoring Guide

Unit 8 Progress Check: MCQ

The will be higher than 4.2 because increasing the concentration of the weak acid decreases

A

the percent ionization.

The will be higher than 4.2 because, for weak acid solutions, the

B

the initial concentration of the weak acid.

is directly proportional to

The will be lower than 4.2 because increasing the concentration of the weak acid produces

C

more

to establish equilibrium.

The will be lower than 4.2 because the

D

concentration of the weak acid.

of the weak acid is inversely proportional to the initial

10. The weak acid

has a

and

calculate the of the solution?

A

of 4.76. A solution is prepared by mixing

of

of

. Which of the following can be used to

B

C

D

11. Which of the following provides the correct mathematical expression to calculate the of a

solution made by mixing

of

and

of

at

?

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