1. At 35^oC, K_c=0.0959 for the reaction below.

H₂ + Cl₂ --> 2 HCl

In an experiment carried out at 35^oC, the initial concentrations were [H₂]=[Cl₂]=[HCl]=1.50mol/L. What is the equilibrium concentration of HCl?

2. Some CH₄(g), intially at 1.000 atm, is placed in an empty reaction vessel. At equilibrium, the total pressure is 1.981 atm. Assuming the partial pressures are in atmospheres, what is K_p for the reaction below?

2 CH₄(g)  →  C₂H₂(g) + 3 H₂(g)

3. Consider the following reaction.

BaSO₄(s) →  Ba²⁺(aq) + SO₄^2-(aq)^,        K_c  = [Ba²⁺] [SO₄^2- ]  = 1.08x10^-10

A solution is prepared by adding some solid BaSO₄ to water and allowing the solid to come to equilibrium with the solution.  What are the concentrations of Ba²⁺ and SO₄^2- in the solution?  

4.    Suppose that A and B react to form C according to the equation below.

A + 2B → C

What are the equilibrium concentrations of A, B and C if 1.5 mol A and 1.5 mol B are added to a 1.0 L flask? Assume that the equilibrium constant for this reaction is K_c = 4.9x10¹¹.

5. A solution is prepared by adding some solid SrF₂ to water and allowing the solid to come to equilibrium with the solution.  The equilibrium constant for the reaction below is K_c = 7.9x10^-10.

SrF₂(s) → Sr²⁺(aq) + 2 F ^-(aq)

What is the equilibrium concentration of Sr²⁺ in the solution? Assume that some of the solid remains undissolved.

6.  At 2000 K, K_c = 0.154 for the reaction below.

2 CH₄(g) → C₂H₂(g) + 3 H₂(g)

If a 1.75-L equilibrium mixture at 2000 K contains 0.15 mol each of CH₄(g) and H₂(g), answer the following questions.

(a) What is the mole fraction of CH₄ present?  (Note: The mole fraction of CH₄ is equal to the number of moles of CH₄ divided by the total number of moles.)

Enter your answer with 2 significant digits.
Enter scientific notation as 1.23E4.
Enter only numbers in your answer. (Do not include units.)

The mole fraction of CH₄ is  ____________ 

 (b) If the equilibrium mixture at 2000 K is transferred from a 1.75-L flask to 1.50-L flask, will the number of moles of CH₄(g) increase, decrease, or remain unchanged?

I have attempted the questions however I keep getting it incorrect.

My answers

1. 2.75M

2. Kp=16210

3. 1.039x10^-5

4. [A]=1.056 [B]=0.61237 [C]=0.443813

5. 0.053M

6. I am not really sure how to solve it