Effect of Surface Area on Rate

Question 1

Surface Area: Volume ratio.

Answer 1

• Smaller sized blocks of reactant have a greater surface area to volume ratio than larger blocks.
• More particles are on the surface so more collisions per second.
• Rate of reaction increases.

Question 2

How do we measure this using a practical?

Answer 2

• Using marble chips which contain calcium carbonate, this can react with hydrochloric acid that produces co2 gas when produced.
• we can meausure the volume of co2 gas which is being produced by using a measuring cylinder to measure ther rate of reaction.
• ## Change the surface area of the marble chips.

Question 3

What is the problems for this practicle?

Answer 3

• Measuring the volume of gas is difficult as bubbles may move rapidly.
• ## Use a gas syringe for accurate results.

Question 4

What is the 2nd way in which we can carry out this practical?

Answer 4

Measuring the mass of co2 that is lost.

1) Place the reaction on a balance, as co2 is produced the mass decreases.
2) Use this to calculate rate of reaction.

Question 5

Why do we have cotton wool on the flask?

Answer 5

• Allows carbon dioxide gas to escape.
• Prevents acid from splashing out of the flask: as if any acid had escaped it could cause the mass to decrease more than it should.
• Anomalie.