Pressure and Reversible Reactions

• What principle explains how a system at equilibrium responds to changes in conditions?

  Le Chatelier's principle
• What happens to the position of equilibrium when pressure is increased in a reversible reaction?

  • Equilibrium shifts to the side with fewer molecules
• What happens to the position of equilibrium when pressure is decreased in a reversible reaction?

  • Equilibrium shifts to the side with more molecules
• How does the pressure of a gas depend on the number of molecules?

  The pressure of a gas increases with the number of molecules.
• In the reaction of nitrogen and hydrogen to form ammonia, how many molecules are present on the right-hand side?

  Two molecules of ammonia.
• In the reaction of nitrogen and hydrogen to form ammonia, how many molecules are present on the left-hand side?

  Four molecules (one nitrogen and three hydrogen).
• What is the effect of increasing pressure on the equilibrium position of the nitrogen and hydrogen reaction forming ammonia?

  • Equilibrium shifts to the right-hand side (fewer molecules).
• What is the effect of decreasing pressure on the equilibrium position of the nitrogen and hydrogen reaction forming ammonia?

  • Equilibrium shifts to the left-hand side (more molecules).
• In the reaction of iodine and hydrogen to form hydrogen iodide, how many molecules are present on both sides?

  Two molecules on both sides.
• What is the effect of changing pressure on the equilibrium position of the iodine and hydrogen reaction forming hydrogen iodide?

  • Changing pressure has no effect on the position of equilibrium.