# Worksheet: Reactions on Surfaces

In this worksheet, we will practice describing the effect of surface area on reaction rates, considering how collision frequency scales with surface area.

**Q1: **

A student is performing a catalytic cracking of liquid paraffin, using porcelain chips as the catalyst. To accelerate the reaction, the surface area of the porcelain chips must be increased. Which of the following tools would be most suitable for this task?

- APestle and mortar
- BCalipers
- CBunsen burner
- DGlass rod
- EIce-water bath

**Q2: **

Consider a cube with sides that are exactly 10 cm long, as shown:

What is the volume of the cube?

What is the surface area of the cube?

If the cube were cut in two, would the total volume and the total surface area increase, decrease, or stay the same?

- AThe total volume would increase and the total surface area would stay the same.
- BThe total volume would stay the same and the surface area would decrease.
- CThe total volume would decrease and the total surface area would increase.
- DThe total volume would stay the same and the total surface area would increase.
- EThe total volume and total surface area would both stay the same.

**Q3: **

The following combinations of shapes all have the same total volume. Which has the greatest total surface area?

- A
- B
- C
- D

**Q5: **

An insoluble solid is reacted with dilute acid. Why does breaking up the solid into smaller particles increase the rate at which it can react?

- ASplitting the solid into smaller particles increases the kinetic energy of colliding molecules.
- BReducing the particle size of the solid allows more molecules to dissolve and collide with acid molecules.
- CIncreasing the surface area of the solid results in more collisions with acid molecules.
- DBreaking bonds between molecules in the solid liberates bonding electrons to react with acid molecules.
- EWeakening the interactions between molecules in the solid produces gaps to accommodate acid molecules.