Consider the gas-phase reaction, 2 SO_{2} + O_{2} <=> 2 SO_{3}, for which K_{p} = 2 at a given temperature. If the mixture is analyzed and found to contain 3.1 bar of SO_{2}, 0.9 bar of O_{2} and 4.1 bar of SO_{3}, describe the situation (remembering significant figures).

We are being asked to **describe the situation for a system where a reaction: **

2 SO_{2} + O_{2} ↔ 2 SO_{3 }

and given the partial pressures: 3.1 bar of SO_{2}, 0.9 bar of O_{2} and 4.1 bar of SO_{3}

We will use the **reaction quotient, Q**, to determine if the chemical reaction would be at equilibrium or not. The *formula for Q* is:

$\overline{){\mathbf{Q}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}\frac{\mathbf{products}}{\mathbf{reactants}}}$

Depending on if Q is greater than or less than K, our reaction will shift to attain equilibrium by reaching the equilibrium constant K:

The Reaction Quotient

The Reaction Quotient

The Reaction Quotient

The Reaction Quotient