1. Sulfur trioxide is an important precursor to the production of sulfuric acid on an industrial level. The equation of the chemical reaction is given below. 2SO 2 (g) + O 2 (g) ⇌ 2SO 3 (g) ΔH = -197 kJ mol -1 You are working for a factory producing sulfuric acid and you want to maximize the yield of sulfur trioxide. How would you change the conditions to achieve that? (Use the table on Le Chatelier’s principle to help you answer this question.)

2. Writing equilibrium constants

3. Write the equilibrium constant for this system: 4NO 2 (g) + O 2 (g) 2N 2 O 5 (g) Products on top Reactants on bottom Coefficients (numbers) become exponents [N2O5][N2O5] 24[NO 2 ][O2][O2]

4. Write the equilibrium constant for this system: Cu 2+ (aq) + 4NH 3 (aq) [Cu(NH 3 ) 4 ] 2+ (aq) [Cu 2+ ] [NH 3 ] [[Cu(NH 3 ) 4 ] 2+ ] 4 Ions keep their charges within the equilibrium constant expression.

5. Write the equilibrium constant for this system: CH 3 COOH(aq) + H 2 O(l) CH 3 COO – (aq) + H 3 O + (aq) [CH 3 COOH] [CH 3 COO – ][H3O+][H3O+] Do not write [H 2 O] in the expression for K c for aqueous solutions like this one.

6. We have done: -What chemical equilibrium is, the existence of forward and reverse reaction. - We know that reactions are happening in both directions with no overall change because the rate is the same. - We know that Kc is a measure of the extent to which the equilibrium favors products or reactants. - And we can write the expression for Kc, (don’t have to calculate it, that’s for next year).