Untitled Quiz

Setting up K from equilibrium expression

• Set up the equation with species on right side over species on left.

• For gases, use P, for solutions, use molarity, [ ].

• Make sure to include to coefficient of balance equation as exponents.

• Do NOT include solids or pure liquids. These have an activity = 1

• Ex: Don’t include H2O (l) or solids like Cu (s), NaCl (s), etc.

When setting up K for an equilibrium expression,

which of the following will be found in the

expression?

• 1. The pressure of oxygen gas

• 2. The concentration of water

• 3. The concentration of NaCl (s)

• 4. The concentration of Ag metal

If Q<K the reaction shifts

• right.

• left.

If Q>K the reaction shifts

• right.

• left.

• Q = 0.01

  shifts right

• Q = 0.01

  shifts left

• Q = 0.03

  shifts right

• Q = 0.03

  shifts left

The reaction 2A à B + C has a Kc of 0.2. The

reaction is commenced with initial

concentrations [A] = 0.2 M, [B] = 0.2 M and

[C] = 0.2 M. In what direction does the

reaction occur?

• 1. The reaction shifts to the right to reach

  equilibrium.

• 2. The reaction shifts to the left to reach

  equilibrium

• 3. The reaction is already at equilibrium.

• 4. Cannot be determined without knowing

  the temperature.

Calculating equilibrium concentrations from K

• 1. Create a RICE table for reaction.

• 2. Insert initial concentrations.

• 3. Use stoichiometry to find change in terms of 1 variable.

• 4. Find equilibrium values in terms of unknown variables.

• 5. Insert into K equation and solve.

Consider the reaction H2(g) + I2(s) à 2HI(g). If the initial

concentration of HI is 2 atm and H2 is 0 atm, what is

the amount of H2 at equilibrium if K = 2?

• 1. 0.5 atm

• 2. 1 atm

• 3. 0.25 atm

• 4. 0.75 atm