Consider the chemical reaction that occurs when Copper(II) oxide reacts with met
ID: 494012 • Letter: C
Question
Consider the chemical reaction that occurs when Copper(II) oxide reacts with methane gas: 4 Cu O(s) + CH_4 (g) CO_2 (g) + 4 Cu (s) + 2H_2 O(g) K_c = 1.10 A reaction mixture contains 0.22 M CH_4, 0.67 M CO_2 and 1.3 M H_2O. Which of the following statements best describes this system once it has reached equilibrium? The concentration of H_2O will be larger than 1.3 The equilibrium constant [K_c] will be bigger than 1.10. The reaction quotient (Q) will be bigger than 1.10 The concentration of CH_4 will beequalto0.22 M. The concentration of CH_4 will be bigger than 0.22 M.Explanation / Answer
Kc includes only gases, so ignore solids in Kc expression:
Kc = [CO2][H2O]^2 / [CH4]
initially
[CH4] = 0.22
[CO2] = 0.67
[H2O] = 1.3
calculate the initial quotient
Q = [CO2][H2O]^2 / [CH4] = (0.67)(1.3^2)/(0.22) = 5.1468
since Q > K
there is excess products, so the reaction will shift toward reactants
meaning:
a) is less, since H2O will react back
b) K can't change with concentrations, only Temperature
c) Q > K, so this is true
d) CH4 will change most likely
e) CH4 is true as well, since it will increase as H2O reacts back