Rate of Reaction

What is rate of reaction?

A measure of how quickly a reactant is used up or a product is formed.

What must reactant particles have/do?

Have enough energy and be colliding with eachother.

What makes a collision successful?

If it produces a reaction.

What is activation energy?

The minimum amount of energy needed for a successful collision.

What 4 factors affect rate of reaction?

Volume, frequency of collisions, activation energy and kinetic energy of the particles.

What happens if you increase pressure and why?

Rate of reaction increases as there is more reactant particles in a smaller volume so more frequent and successful collisions.

What happens if you increase concentration and why?

Increase in rate of reaction because more reactant particles in a volume so more frequent and successful collisions.

What happens if you increase temperature and why?

Increase in rate of reaction because particles have more kinetic energy so more frequent and successful collisions per second.

What happens if you increase surface area and why?

Increase in rate of reaction because there is a greater area of particles exposed so more frequent and successful collisions.

What is a catalyst?

A substance that speeds up the rate of the reaction without being altered or consumed during the reaction.

How do catalysts work?

They provide an alternate reaction pathway which has lower activation energy.

What catalyses the Haber process?

Iron

What is the method for the required practical : measuring gas production?

1. Support a gas syringe with a stand, boss and clamp.

2. Use a measuring cylinder to add 50cm of dilute hydrochloric acid to a conical flask.

3. Add 0.4g of calcium carbonate and connect the gas syringe and start a stopwatch.

4. Every 10 seconds record the volume of gas produced.

5. Repeat with different concentrations of hydrochloric acid.

6. Calculate mean rate of reaction and plot a graph.

What are the hazards of the measuring gas production practical?

HCl causes eye irritation so wear goggles and don’t look through the top of the flask.

What is the method for the investigating rate of reaction by colour change required practical?

1. Use a measuring cylinder to add 50cm of dilute sodium thiosulfate solution to a conical flask.

2. Place the conical flask on top of a piece of paper with a black cross on it.

3. Add 10cm of dilute hydrochloric acid and swirl, start a stopwatch.

4. Look down the reaction mixture and when the cross can’t be seen stop the timer.

5. Measure and record the temperature of the solution.

6. Repeat with different temperatures of sodium thiosulfate solution.