Chemical Equilibrium

 JUST A SHORT BREAK TO REFRESH YPUR MINDS ABOUT YESTERDAY'S LESSON
http://www.chem1.com/acad/webtext/chemeq/

EVALUATION:
1. Given the phase equilibrium at a pressure of 1 atmosphere:

H₂O_(s)  H₂O_(l)

What is the temperature of the equilibrium mixture?
a) 273C
b) 273 K
c) 373C
d) 373 K

2. Given the reaction at equilibrium:

N_2(g) + 3 H_2(g)  2 NH_3(g) + 22 kcal

Which stress would cause the equilibrium to shift to the left?
a) increasing the temperature
b) increasing the pressure
c) adding N_2(g) to the system
d) adding H_2(g) to the system

3. The solubility of PbS in water is 3 x 10^-14 M. What is the solubility product constant, K_sp, for PbS?
a) 9 x 10^-7
b) 3 x 10^-28
c) 3 x 10^-14
d) 9 x 10^-28

4. Given the reaction at equilibrium:

BaCrO_4(s)  Ba²⁺_(aq) + CrO₄^2-_(aq)

Which substance, when added to the mixture, will cause an increase in the amount of BaCrO_4(s)?
a) K₂CO₃
b) CaCO₃
c) BaCl₂
d) CaCl₂

5. Given the reaction:

A₂B  2 A⁺_(aq) + B^2-_(aq)

What is the solubility product constant expression (K_sp) for the reaction?
a) 2[A⁺][B^2-]
b) 2[A⁺] + [B^2-]
c) [A⁺]²[B^2-]
d) [A⁺]² + [B^2-]

6. Which factors must be equal when a reversible chemical process reaches equilibrium?
a) mass of the reactants and mass of the products
b) rate of the forward reaction and rate of the reverse reaction
c) concentration of the reactants and concentration of the products
d) activation energy of the forward reaction and activation energy of the reverse reaction

7. Given the reaction at equilibrium:

2 SO_2(g) + O_2(g)  2 SO_3(g) + heat

The concentration of SO_3(g) may be increased by
a) decreasing the concentration of SO_2(g)
b) decreasing the concentration of O_2(g)
c) increasing the pressure
d) increasing the temperature

AB_(s)  A⁺_(aq) + B^-_(aq)

8. Which is the correct equilibrium expression for the system above? 
a)      c)

b)      d)


9. Given the reaction at equilibrium:

AgBr_(s)  Ag⁺_(aq) + Br^-_(aq)

Which change occurs when KBr_(s) is dissolved in the reaction mixture?
a) The concentration of Ag⁺_(aq) decreases.
b) The concentration of Ag⁺_(aq) remains the same.
c) The amount of AgBr_(s) decreases.
d) The amount of AgBr_(s) remains the same.

10. For which of the following reactions will the equilibrium constants K_c and K_p have the same value?
a) 2 CO_2(g) 2 CO_(g) + O_2(g)
b) H₂O_{(g) +} CO_(g)  H_2(g) + CO_2(g)
c) 3 O_2(g)  2 O_3(g)
d) CO_(g) + Cl_2(g) COCl_2(g)


-au revoir