Chemistry

Need help in AP chemistry on Equilibrium

When heated, hydrogen sulfide gas decomposes according to the equation
2 H2S(g) ⇄ 2 H2(g) + S2(g)

A 3.40 g sample of H2S(g) is introduced into an evacuated rigid 1.25 L container. The sealed
container is heated to 483 K, and 3.72 x 10
-2
mol of S2(g) is present at equilibrium.

(a) Write the expression for the equilibrium constant, Kc, for the decomposition reaction
represented above.

(b) Calculate the equilibrium concentration, in mol L
-1
, of the following gases in the container
at 483 K.
(i) H2(g)
(ii) H2S (g)

(c) Calculate the value of the equilibrium constant, Kc, for the decomposition reaction at 483 K.

(d) For the reaction H2(g) + ½ S2(g) ↔ H2S(g) at 483 K, calculate the value of the equilibrium
constant, Kc.

(e) Calculate the partial pressure of S2(g) in the container at equilibrium at 483 K

  1. 0
asked by Sam
  1. a. mols H2S = grams/molar mass = 3.40/34 = 0.1
    Surely I don't need to write the Kc expression for you.

    b.
    ..........2H2S ==> 2H2 + S2
    initial..0.1........0.....0
    change....2x.......2x.....x
    equil...0.1-2x.....2x.....x

    From the problem, (S2) = x = 0.0372.
    Therefore, (H2) is 2x
    (H2S) = 0.1-2x
    You can do the arithmetic.

    c. Substitute the values of concns into Kc and solve for Kc.

    d. The problem asks for the original Kc but half of it and reversed. Take square root to take care of the 1/2 part and take the reciprocal to take care of the reversed part.

    e. Use PV = nRT.
    Post your work if you get stuck.

    posted by DrBob222
  2. Note that I dropped a - sign here on the change of -2x. The equil value of 0.1-2x is correct as written.
    b.
    ..........2H2S ==> 2H2 + S2
    initial..0.1........0.....0
    change....2x.......2x.....x
    equil...0.1-2x.....2x.....x

    posted by DrBob222

Respond to this Question

First Name

Your Response

Similar Questions

  1. chemistry

    I am a freshman in college, and am taking a placement test soon, but haven't seen chemistry since 10th grade. I'd appreciate any help I can get from anyone here to help me solve this problem: Hydrogen and sulfur chemically combine
  2. chemistry

    Write word equations for the following chemical reactions. a. Pure copper can be produced by heating copper(II) sulfide in the presence of diatomic oxygen from the air. Sulfur dioxide gas is also produced in this reaction. b.
  3. Chem 112

    An equilibrium was established after 0.100 mol of hydrogen gas and 0.100mol of iodine gas were added to an empty 1.00L reaction vessel and heated to 700K. The color intensity of the mixture changed from deep purple to a lighter
  4. chemistry

    2H2(g) + S2(g) ¡ê 2H2S(g) Analysis of the contents of a 15.0L flask reveals that there are 4.4 moles of hydrogen gas, 2.0 moles of sulfur gas, and 3.7 moles of hydrogen sulfide gas in the flask at equilibrium. Calculate the
  5. Chemistry

    2. Solid ammonium iodide decomposes to yield ammonia gas(NH3) and hydrogen iodide gas at 400oF. The equilibrium constant for this reaction is 0.215. Ten grams of ammonium iodide are sealed in a 10.0 L flask at equilibrium.
  6. Chemistry

    When 0.20 mol of hydrogen gas and 0.15 mol of iodine gas are heated at 723 K until equilibrium is established, the equilibrium mixture is found to contain 0.26 mol of hydrogen iodide. The equation for the reaction is as follows.
  7. chemistry

    Write Skeleton equations for these reactions. A) Heating Copper(II) sulfide in the Presence of diatomic oxygen produces pure copper and sulfur dioxide gas. B)When heated, baking soda (Sodium hydrogen carbonate) decomposes to form
  8. science

    methanol gas decomposes into carbon dioxide and hydrogen gas. At 327 degrees celcius, the equilibrium concentration are methanol is 0.15M, and hydrogen is 1.1M for the reaction calculate the Kp at this temperature.
  9. Bio 20

    Hydrogen sulfide gas is combusted with oxygen gas to produce sulfur dioxide gas and water vapour. If there is 19.3 L of oxygen gas, what maximum volume of hydrogen sulfide gas could be combusted?
  10. AP Chem

    a 4.22 gram sample of copper II sulfide was added to excess hydrocholoric acid with hydrogen sulfide gas being generated and collected over water. What volume of hydrogen sulfide gas would be collected at 32 degrees Celcius and

More Similar Questions