# Equilibrium Essay

1413 Words6 Pages
Equilibrium – Solving Equilibrium Problems Date______________________ Knowing the equilibrium constant allows us to predict and calculate what the equilibrium concentration of each substance will be at equilibrium. This works for all three types of equilibrium (phase, solubility, and chemical). These questions can involve some tricky algebra, but there are some short cuts we will learn to help us solve them. We will look at three different types of equilibrium problems. However, in all cases, the question is solved exactly the same way, by following these steps: 1. | 2. | 3. | Problem 1 – Perfect Squares Consider the reaction of carbon monoxide and water to form carbon dioxide and hydrogen. CO(g) + H2O(g) ↔ CO2(g) + H2(g) Suppose you start with 1.00 mol each of CO and H2O in a 50.0 L vessel. How many moles of each substance are in the equilibrium mixture if the Kc is 0.58? Homework Page 472 #5,6 Problem Sheet Equilibrium Constant Problems 1. What is the equilibrium composition of a reaction mixture if you start with 0.055 mol each of H2 and I2 in a 1.0 L vessel? The reaction is a synthesis. The Kc for this reaction is Kc = 49.7 at 458oC [Answer: [H2] = [I2] = 1.2 × 10-2 M, [HI] = 8.6 × 10-2 M] 2. Iodine and bromine react to give iodine monobromide, IBr. What is the equilibrium composition of a mixture at 150oC that initially contained 0.0015 mol each of iodine and bromine in a 5.0 L vessel? The equilibrium constant Kc for this reaction at 150oC is 1.2 102. [Answer: [I2] = [Br2] = 4.6 10-5 M, [IBr] = 5.1 10-4 M] 3. Initially a mixture contains 0.850 mol each of N2 and O2 in an 8.00 L vessel. Find the composition of the mixture when equilibrium is reached at 3900oC. N2 and O2 react to form nitrogen monoxide. Kc at 3900oC is 0.0123. [Answer: [N2] = [O2] = 0.101 M, [NO] = 0.0112 M] Equilibrium