A) write a balanced equation for the reaction?

Question

at 227°C, carbon monoxide gas reacts with hydrogen gas to form one mole of methanol, CH3OH. At equilibrium, the partial pressures of the gases are Pco=0.295atm, Ph2=1.25atm, and PCH3Oh=2.18atm.
A) write a balanced equation for the reaction
b) calculate the equilibrium constant for the reaction

Answer 1

a.) Step 1: Write the unbalanced equation, and count out the number of atoms on each side:
CO + H2 -> CH3OH

1 C -> 1 C
1 O -> 1 O
2 H -> 4 H

Step 2: Given the above totals, balance the equation:
The only change you need, is to double the Hydrogen in the reactant side.
CO + 2H2 -> CH3OH (solution!)

b.) For: aA + bB = cC + dD, K may be defined as;

K = (P(C)^c * P(D)^d) / (P(A)^a * P(B)^b), i.e., the pressures of the reactants over the products, with the pressures raised to the coefficients of the reactants.

For this reaction:
a = 1
A = .295 atm
b = 2
B = 1.25 atm
c = 1
C = 2.18 atm
d and D are ignored.

Thus, K = 2.18^1 / (.295^1 * 1.25^2)
K = 2.18 / (2.95 * 1.5625)
K = 2.18 / 4.609375
K = 0.473 (solution!)