Rates and equilibrium for OCR GCSE Chemistry

This page covers the following topics:

1. Rate of reaction

The rate of a chemical reaction can be increased by increasing temperature, increasing reactant concentration, increasing the surface area of solid reactants or the use of catalysts. There are a number of ways we can determine the rate of reaction experimentally.

1

What is a catalyst?

A compound that increases the rate of reaction without being chemically altered or used up at the end of the reaction.

2

What does the gradient represent on a graph of total mass of product produced vs time from start of reaction?

rate of reaction

3

12 g of reactant is used up after 45 seconds, what is the rate of reaction?

0.27 g s⁻¹

4

What are the units of the rate of reaction when CO₂ gas is released over 30 seconds?

cm³ s⁻¹

5

HCl was added to sodium thiosulfate solution in a conical flask, the resulting solution going from transparent to opaque after 64 seconds. What is the rate of the reaction?

0.016 s⁻¹

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