Lesson Worksheet: Le Chatelier’s Principle Chemistry • 10th Grade

In this worksheet, we will practice explaining the effect of changing the temperature, concentration, or pressure on an equilibrium according to Le Chatelier’s principle.

Q1:

In which of the following gas-phase reactions could the equilibrium yield be increased by increasing temperature or decreasing pressure?

  • ANO2NO,+57.2kJ/mol242Δ𝐻=
  • BCl+OClO+O,-29.9kJ/mol32Δ𝐻=
  • CCO+HOCO+H,-41.0kJ/mol222Δ𝐻=
  • D2SClSCl+Cl,+40.6kJ/mol2222Δ𝐻=
  • E2SO+O2SO,-196kJ/mol223Δ𝐻=

Q2:

In which of the following gas-phase reactions could the equilibrium yield be increased by increasing either temperature or pressure?

  • ANO+ONO+O,-200kJ/mol322Δ𝐻=
  • BN+2O2NO,+66.4kJ/mol222Δ𝐻=
  • CN+O2NO,+181kJ/mol22Δ𝐻=
  • DN+3H2NH,-92.2kJ/mol223Δ𝐻=
  • ENO4NO+O,+110kJ/mol2522Δ𝐻=

Q3:

Molecules A and B react exothermically and reversibly to produce a third molecule C, as shown by the equation.

A box contains five molecules each of A, B, and C at equilibrium, as shown. The temperature inside the box is 25C, and the pressure is 1 bar.

The temperature of the box changes to 50C, and the box expands to maintain a pressure of 1 bar. Which of the following diagrams represents the box at equilibrium under these conditions?

  • A
  • B
  • C
  • D
  • E

The volume of the box increases at a fixed temperature of 25C. Which of the following diagrams represents the box at equilibrium under these conditions?

  • A
  • B
  • C
  • D
  • E

At a fixed temperature of 25C, the concentration of B is increased and the box changes in volume to maintain a pressure of 1 bar. Which of the following diagrams represents the box at equilibrium under these conditions?

  • A
  • B
  • C
  • D
  • E

At a fixed temperature of 25C, the concentration of C is decreased and the box changes in volume to maintain a pressure of 1 bar. Which of the following diagrams represents the box at equilibrium under these conditions?

  • A
  • B
  • C
  • D
  • E

Q4:

The following reaction is part of the Ostwald process that produces nitric acid: 4NH()+5O()4NO()+6HO()322gggg

Which of the following statements explains why the percentage of NO produced may decrease as the pressure increases?

  • AIncreasing the pressure moves the equilibrium to the right.
  • BThe forward reaction is favored by an increase in pressure.
  • CThe total volume of gas increases for the backward reaction.
  • DFewer moles of gas are on the reactant’s side.

Q5:

Consider the following equation: 3Fe()+4HO()FeO()+4H()sgsg2342 What effect will increasing the pressure have on the position of the equilibrium?

  • AThe equilibrium will move to the right.
  • BThe equilibrium will not move.
  • CThe equilibrium will move to the left.

Q6:

Sulfur trioxide is produced as part of the process of manufacturing sulfuric acid as shown: 2SO()+O()2SO()kJmol223gggΔ𝐻=196/ What effect will adding more oxygen have on the position of the equilibrium?

  • AThe equilibrium will not move.
  • BThe equilibrium will move to the right.
  • CThe equilibrium will move to the left.

Q7:

The industrial production of ammonia uses nitrogen and hydrogen: N()+3H()2NH()223ggg

What effect will increasing the pressure have on the position of the equilibrium?

  • AThe equilibrium will move to the left.
  • BThe equilibrium will not move.
  • CThe equilibrium will move to the right.

Q8:

The industrial production of ethanol uses ethene gas and steam, as shown: CH()+HO()CHOH()24225ggg

Considering that the forward reaction is exothermic, what effect will increasing the temperature have on the position of the equilibrium?

  • AThe equilibrium will not move.
  • BThe equilibrium will move to the left.
  • CThe equilibrium will move to the right.

Q9:

Which of the following statements best defines Le Chatelier’s principle?

  • AIf conditions change in a dynamic equilibrium, the position of the equilibrium moves to increase the change.
  • BIf a chemical reaction is at equilibrium and experiences a change in pressure, temperature, or concentration of products or reactants, the equilibrium shifts in the opposite direction to increase the rate of reaction.
  • CIf a change occurs to an equilibrium mixture, the system will tend to adjust itself so as to cancel out, as far as possible, the effect of that change.
  • DChanges in the temperature and pressure in a system will result in changes to the system in order to achieve a new equilibrium state.
  • EWhen a system at equilibrium is subjected to changes in concentration or volume, the system shifts to a new equilibrium to counteract the applied change.

Q10:

Iodine trichloride is a bright yellow interhalogen compound formed in the following reaction: ICl+ClICl23 What effect will removing chlorine have on the position of the equilibrium?

  • AThe equilibrium will move to the right.
  • BThe equilibrium will move to the left.
  • CThe equilibrium will not move.

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