The Dynamic Dance: Reversible Reactions and Le Chatelier's Principle

• Chemistry
• Upper Secondary (Key Stage 4)
• GCSE

Dynamic Equilibrium

Answer these questions on paper and then get your Chromebooks out

1) What are the 4 factors that affect the rate of reaction?

2) What are the 4 state symbols?

3) Name 4 types of reaction

4) Why does graphite conduct electricity but diamond doesn't?

Slide 3: Dynamic Equilibrium

Dynamic equilibrium is a state where the rate of the forward reaction is equal to the rate of the reverse reaction. In this state, the concentrations of reactants and products remain constant over time.

What is a reversible reaction?

1. A reaction that only proceeds in one direction
2. A reaction that produces a lot of heat
3. A reaction that involves two elements
4. A reaction that can proceed in both directions

What is equilibrium in a chemical reaction?

1. A state in which the reaction proceeds very slowly
2. A state in which the reaction stops completely
3. A state in which only the forward reaction occurs
4. A state in which the forward and reverse reactions occur at the same rate

What happens to the concentration of reactants and products at equilibrium?

1. The concentrations increase over time
2. The concentrations decrease over time
3. The concentrations fluctuate randomly
4. The concentrations remain constant

What factors can affect the position of equilibrium?

1. Temperature, pressure, and concentration
2. Time, volume, and mass
3. Density, viscosity, and pH
4. Color, odor, and texture

What does Le Chatelier's principle state?

1. A system at equilibrium will respond to a stress by shifting to counteract the stress.
2. A system at equilibrium will respond to a stress by accelerating the reaction.
3. A system at equilibrium will respond to a stress by maintaining equilibrium.
4. A system at equilibrium will respond to a stress by ignoring the stress.

Slide 6: Effect of Temperature Changes

Increasing the temperature of an exothermic reaction shifts the equilibrium towards the left, favoring the reactants. Decreasing the temperature has the opposite effect.

How does an increase in temperature affect an exothermic reaction at equilibrium?

1. The system will shift to the left, favoring the reactants.
2. The temperature has no effect on the system.
3. The reaction will stop.
4. The system will shift to the right, favoring the products.

If the concentration of reactants in a system at equilibrium is increased, what will happen?

1. The system will stop reacting.
2. The system will shift to form more reactants.
3. The system will remain at equilibrium.
4. The system will shift to form more products.

What effect will adding more Cl2 have on the colour of the mixture?

What effect will removing Cl2 have on the colour of the mixture?

Slide 7: Effect of Pressure Changes

Increasing the pressure in a system with fewer moles of gas will shift the equilibrium towards the side with fewer gas molecules. Decreasing the pressure has the opposite effect.

What will happen if the pressure is increased in a system at equilibrium with fewer moles of gas on the reactant side?

1. The system will shift to the side with more moles of gas.
2. The system will remain at equilibrium.
3. The system will shift to the side with fewer moles of gas.
4. The pressure has no effect on the system.

Slide 9: Catalysts and Equilibrium

Catalysts do not affect the position of equilibrium but can increase the rate at which equilibrium is reached. They provide an alternative reaction pathway with a lower activation energy.