AP Chem Unit 07 In Class Exam OVERALL

For the reaction

A(g) + B(g) ⇄ 2C(g)

∆G^◦_rxn = -10.0 kJ/mol at 100◦C. If you have a mixture with a P_A=2.00 atm, P_B=1.00 atm, and P_C=6.00 atm in a container at 100◦C, which of the following is true?

• the reaction is at equilibrium

• the reaction will move toward the reactants to reach equilibrium.

• the mixture can never achieve equilibrium.

• the reaction will move toward the products to reach equilibrium.

Tags

NGSS.HS-PS1-7

Given the following equilibrium data at 250⁰C

2 NO(g) ↔ N₂(g) + O₂(g) K_c1 = 1 x 10³

N₂(g) + Br₂(g) + O₂(g) ↔ 2 NOBr(g) K_c2 = 2 x 10^-2

Calculate the equilibrium constant for the reaction below at 250⁰C

2 NO(g) + Br₂(g) ↔ 2 NOBr(g) K_c3 = ?

• 50,000

• 1,000.02

• 20

• 999.98

Tags

NGSS.HS-PS1-7

The numerical value of the concentration equilibrium constant, K, for the equilibrium reaction

X(aq) ⇄ Y(aq) + 2Z(aq)

is 10. at 25⁰C. When a reaction mixture is brought to equilibrium, [Y] is found to be 2.0 M and [Z] is found to be 4.0 M. What is the [X] at equilibrium in this reaction mixture?

• 10.8 M

• 1.8 M

• 0.32 M

• 3.2 M

Tags

NGSS.HS-PS1-7

H₂ and I₂ are combined in a flask and allowed to react according to the reaction:

H₂(g) + I₂(g) ↔ 2HI(g)

Examine the figures (sequential in time). Which figure represents the point at which equilibrium is reached? Why?

• v; at this point concentrations of products and reactants remain constant

• v; at this point there is greater product than reactant

• ii; at this point concentrations of products and reactants remain constant

• ii; at this point there is greater reactant than product

Tags

NGSS.HS-PS1-5

Suppose the reaction

A(aq) + 3 B(aq) ⇌ 2 C(aq)

has a value of K = 10.0 at a certain temperature. If 0.5 moles of A, 0.5 moles of B and 0.5 moles of C are placed in a 5 L solution, which direction would the reaction initially proceed?

• The reaction will shift to form product because Q > K.

• The reaction will shift to form product because Q < K.

• The reaction will shift to form reactants because Q > K.

• The reaction will shift to form reactants because Q < K.

Tags

NGSS.HS-PS1-5

The salt MX₂ has a solubility of 1.0x10^-4 molar.  Determine the solubility product constant, K_sp, for MX₂.

• 1.0x10^-4

• 1.0x10^-8

• 1.0x10^-12

• 4.0x10^-12

A(g) + 2B(g) ⇄ C(g) + 2D(g)

Equal numbers of moles of A and B are placed in a rigid flask at a given temperature and allowed to reach equilibrium according to the equation above. Which of the following must be true at equilibrium?

• The [A] must be less than the [B], and [C] must equal [D].

• The [A] must be less than the [B], and [C] will differ from [D].

• The [A] must be greater than the [B], and [C] must equal [D].

• The [A] must be greater than the [B], and [C] will differ from [D].

Tags

NGSS.HS-PS1-7

2 NO₂(g) ⇄ N₂O₄(g) ΔH^◦< 0

Which of the following would cause the equilibrium to increase the amount of N₂O₄(g) in the mixture?

I. Adding 1.0 mol He(g)

II. Decreasing the volume of the container

III. Adding 1.0 mol N₂O₄(g)

IV. Increasing the temperature

• II and IV only

• II only

• I and III only

• I and II only

Tags

NGSS.HS-PS1-5

CO₂(g) + H₂(g) ⇄ H₂O(g) + CO(g)

H₂O(g) and CO(g) are inserted into an evacuated, rigid flask so that the initial partial pressures of each of them are 2.40atm and 1.80atm respectively. The reaction is carried out at constant temperature. What is the partial pressure of H₂(g) when the partial pressure of H₂O(g) has decreased to 1.60atm?

• 0.80atm

• 1.00atm

• 1.20atm

• 1.60atm

Tags

NGSS.HS-PS1-5

NGSS.HS-PS1-7

A(aq) + B(s) ⇄ C(aq) + D(aq) ΔH = +12.1kJ/mol_rxn

When the reaction above is at equilibrium, the ratio shown can be decreased by doing which of the following?

• Adding He (g)

• Adding a catalyst

• Increasing temperature

• Decreasing temperature

Tags

NGSS.HS-PS1-5