equilibrium constant

• What is the equilibrium constant symbol for a reversible reaction?

  Kc
• What does the equilibrium constant (Kc) measure?

  It measures the position of equilibrium
• What does a large Kc value indicate about the equilibrium position?

  It favors the products at equilibrium
• What does a small Kc value indicate about the equilibrium position?

  It favors the reactants at equilibrium
• What does a Kc value of 1 indicate?

  Reactants and products are equal at equilibrium
• How is the equilibrium constant (Kc) expressed for a general reaction?

  For the reaction: aA + bB ⇌ dD + eE

  • Kc = $\frac{[D]^d[E]^e}{[A]^a[B]^b}$
• What is the Kc expression for the reaction H2(g) + I2(g) ⇌ 2HI(g)?

  Kc = $\frac{[HI]^2}{[H2][I2]}$
• How do you calculate Kc if equilibrium concentrations are known?

  1. Write the Kc expression.
  2. Substitute equilibrium concentrations into the expression.
  3. Calculate the value of Kc.
  4. Determine the units for Kc.
• What must be determined after calculating Kc?

  The units for Kc