Question

Carbon dioxide and water react to form methanol and oxygen, like this:

Answer 1

Answer:

24x10³

Explanation:

2CO₂(g) + 4H₂O(g) → 2CH₃OH(l) + 3O₂ (g)

The equilibrium constant for this reaction is:

Kc = $\frac{[O_2]^3}{[CO_2]^2[H_2O]^4}$

The expression of [CH₃OH] is left out as it is a pure liquid.

Now we convert the given masses of the relevant species into moles, using their respective molar masses:

• CO₂ ⇒ 3.28 g ÷ 44 g/mol = 0.0745 mol CO₂

• H₂O ⇒ 3.86 g ÷ 18 g/mol = 0.214 mol H₂O

• O₂ ⇒ 2.80 g ÷ 32 g/mol = 0.0875 mol O₂

Then we calculate the concentrations:

• [CO₂] = 0.0745 mol / 7.5 L = 0.0099 M

• [H₂O] = 0.214 mol / 7.5 L = 0.0285 M

• [O₂] = 0.0875 mol / 7.5 L = 0.0117 M

Finally we calculate Kc:

• Kc = $\frac{0.0117^3}{0.0099^2*0.0285^4}$ = 24x10³