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

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

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

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

Surface area and rate: analysis

Chemistry

In the Industrial Chemistry unit, pupils will build on their knowledge of reaction rates to learn about the industrial processes involving chemical reactions and the factors that affect them.

In the Energy Changes in Reactions unit, pupils learned about bond breaking, bond making, and reaction profiles.

Rate of reaction

What will we calculate if we determine the gradient at a specific point on a graph of mass of product versus time. 

On a graph of mass of gas produced against time, what does a steeper gradient indicate?

surface area changes the concentration of acid

surface area affects the frequency of collisions

surface area changes the mass of acid used

surface area has no effect on reaction rate

the marble chips are the limiting reactant

Why does the surface area of marble chips affect the rate of reaction but not the total mass of gas produced?

total mass of gas produced × total time of reaction

total time of reaction ÷ total mass of gas produced

total mass of gas produced ÷ total time of reaction

total mass of reactants × total time of reaction

How is the mean rate of reaction calculated?

If 30 grams of gas are produced in 10 minutes, what is the mean rate of reaction?

the same mass of gas is produced for all surface areas

When reacting excess marble chips with acid, how does the surface area of the chips affect the total mass of gas produced?

If you want to make a solid react faster with a liquid, what should you do to the solid?

Why do smaller particles of a solid react faster than larger particles of the same solid?

Which has a greater surface area to volume ratio: 5g of large calcium carbonate chips, 5g of small calcium carbonate chips or 5g of powdered calcium carbonate?

to ensure the experimental results are reliable

Why is it important to control variables in a rate of reaction experiment?

the time taken for the reaction to reach completion

Which of the following should be kept constant in an experiment investigating the effect of surface area on reaction rate?

mass of reacting solid needed for the reaction to reach completion

What will we have calculated if we divide the amount of product made by the time taken?

Starter Quiz