AQA C7 Reversible Reactions

What is a reversible reaction?

• A reaction where products cannot react to form reactants

• A reaction where products can react to form reactants

• A reaction that only occurs in one direction

• A reaction that does not involve energy changes

Which symbol is used to represent a reversible reaction?

• →

• ⇌

• ⇋

• ↔

In the Haber Process, which substances react to form ammonia?

• Hydrogen and oxygen

• Nitrogen and oxygen

• Hydrogen and nitrogen

• Ammonia and nitrogen

What happens to the energy in a reversible reaction?

• Energy is only transferred in one direction

• Energy is lost in the reaction

• The same amount of energy is transferred each way

• Energy is not involved in reversible reactions

What is equilibrium in a chemical reaction?

• When the reaction stops completely

• When the reactions occur at exactly the same rate in each direction

• When only the forward reaction occurs

• When only the reverse reaction occurs

According to Le Chatelier's principle, what happens if a change is made to a system at equilibrium?

• The system remains unchanged

• The system responds to counteract the change

• The system speeds up the reaction

• The system slows down the reaction

What happens if the concentration of reactants is increased in a system at equilibrium?

• More reactant is produced

• The position of equilibrium shifts towards products

• The position of equilibrium shifts towards reactants

• The system remains at equilibrium

What happens if the concentration of products is increased in a system at equilibrium?

• More product is produced

• The position of equilibrium shifts towards reactants

• The position of equilibrium shifts towards products

• The system remains at equilibrium

What happens to the equilibrium position if the temperature is increased in an endothermic reaction?

• Equilibrium moves to the left, producing less product.

• Equilibrium moves to the right, producing more product.

• Equilibrium remains unchanged.

• Equilibrium moves to the right, producing less product.

What is the effect of a decrease in temperature on the yield of an exothermic reaction?

• Decreases yield of reaction

• Increases yield of reaction

• No effect on yield

• Stops the reaction