# Surface area and rate: analysis

I can represent graphically and describe how the rate of reaction depends on the surface area of a solid reactant.

# Surface area and rate: analysis

I can represent graphically and describe how the rate of reaction depends on the surface area of a solid reactant.

## Lesson details

### Key learning points

- The changing rate of a chemical reaction can be represented by a graph of mass of gas produced against time.
- When reacting excess marble chips with acid, the same mass of gas is produced for all surface areas of chips.
- The mean rate of reaction = total mass of gas produced ÷ total time of reaction
- The instantaneous rate of reaction is equal to the gradient of the graph.
- The gradient of a rate of reaction graph can be calculated from a tangent drawn at a point on the curve.

### Common misconception

Students often confuse the mean rate of reaction with the instantaneous rate of reaction, thinking they are the same or not understanding the distinction between the two.

The tasks give students the opportunity to distinguish between mean and instantaneous rate of reaction by calculating both from the same set of data.

### Keywords

Gradient - The gradient on a graph represents the rate at which one quantity changes relative to another.

Mean rate of reaction - The mean rate of reaction is the average rate at which reactants are converted into products in a given time.

Instantaneous rate of reaction - The instantaneous rate of reaction is the rate at which reactants are converted into products at a specific moment in time.

Tangent - A tangent is a straight line that touches a curve at exactly one point without crossing it.

### Equipment

Graph paper for drawing graphs. Ruler or straight edge to draw tangents. Calculator to calculate rate of reaction.

### Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

## Video

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