Section 9 - Reaction Rates and Catalysts

Question 1

What are the three factors that increase the rate of reaction?

Answer 1

• Increasing temperature: the particles tend to have more kinetic energy. This means that they move around faster, and so are more likely to collide with each other and have enough energy to react.
• Increasing concentration (or pressure in gases): this means that the particles of reactant will be closer together, so they will be more likely to collide.
• Increasing the surface area of a solid reactant: this increases the number of particles of the solid reactant able to come into contact with other reactants.

Question 2

Exam q:
Predict whether magnesium dust or magnesium ribbon will react faster with hydrochloric acid

Answer 2

Magnesium dust has a larger surface area than magnesium ribbon. Increasing the surface area of a solid reactant increases the rate of reaction, so magnesium dust will react faster than magnesium ribbon.

Question 3

What does a catalyst do?

Answer 3

A catalyst increases the rate of a reaction by lowering its activation energy

Question 4

What is a catalyst?

Answer 4

A catalyst is any substance which changes the rate of a reaction, without being changed or used up itself

Question 5

What are 2 advantages to using catalysts?

Answer 5

1) Catalysts reduce the need for high temperatures and pressures in industrial reactions, like hydrocarbon cracking and ethanol production. This makes these processes cheaper to run.
2) Using lower temperatures also means less energy demand, and so lower carbon dioxide emissions.