Short Answer 
To analyze the reaction between H2 and I2, the equilibrium expression Kc = [HI]^2 / ([H2][I2]) is established with Kc = 100 and HI concentration at 0.600 M, leading to the calculation of initial concentrations, x, as 0.036 M for both H2 and I2. Consequently, the initial moles of H2 added to the container is determined to be 0.036 mol.
Step 1: Set Up the Equilibrium Expression
To analyze the reaction between H2 and I2, start by establishing the equilibrium expression that relates the concentrations of reactants and products. The equilibrium constant is given as:
- Kc = 100
- Use the expression: Kc = [HI]^2 / ([H2][I2])
- At equilibrium, the concentration of HI is 0.600 M, and since the initial concentrations of H2 and I2 are equal, denote them both as ‘x’. This leads to the equation:
- 100 = (0.600)^2 / x²
Step 2: Solve for x
Next, you need to determine the value of ‘x’, which represents the initial concentrations of H2 and I2. Rearranging the equilibrium expression will help you find ‘x’:
- Calculate: x = sqrt((0.600)^2 / 100)
- Upon solving, you find x = 0.036 M.
- This value indicates the change in concentration of HI at equilibrium.
Step 3: Calculate Initial Moles of H2
Now that you’ve found the initial concentration of H2 is 0.036 M, you can calculate the total number of moles initially added to the container. Since you know the volume of the container is 1.0 L, use the following formula:
- moles = concentration ‚àöo volume
- Applying the values: moles = 0.036 M ‚àöo 1.0 L = 0.036 mol
- Thus, 0.036 moles of H2 were initially added to the container.