Basics of rate of reaction for SQA National 5 Chemistry
This page covers the following topics:
1. Rate of reaction
2. Frequency of collisions
3. Frequency of collisions
Reactions occur due to the collision of different types of molecules which must have enough energy to react with one another, this is called collision theory. The frequency and energy level of these collisions is what determines rate of reaction.
The frequency of successful collisions can be influenced by many factors such as temperature, pressure and concentration of reactants.
The frequency of successful collisions can also be influenced by surface area (of solid reactants) and state of matter (solid/liquid/gas) of the reactants.
Describe the rate of successful collisions in a reaction between two solids.
The particles in mixture of two solids react very slowly or not at all as few particles are able to make contact with each other, thus the frequency of successful collisions is low. For this reason reactions between two solids are rare.
What is the effect on rate of reaction if frequency of successful collisions increases?
Rate of reaction increases
The lines on this graph show the reaction between zinc and hydrochloric acid. Which line indicates the reaction undertaken at a lower temperature?
The reaction shown by the black line.
What two things could you measure to measure rate of reaction?
loss of reactants or formation of products
How does increasing concentration affect the frequency of collision between particles in a chemical reaction?
Increasing concentration increases the frequency of collisions between the particles.
Increasing concentration increases the overall frequency of collisions.
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