# Rates of Equilibrium

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## Rate of Reaction

- can find out the rate of a chemical reaction by monitoring the amount of reactants used up over time

- alternatively, can find out the rate of reaction by measuring the amount of products made over time

- the gradient of the line at any given time on the graph drawn from such an experiment, tells you the rate of reaction, at that time

the steeper the gradient, the faster the reaction

- to calculate the rate of reaction at a specific time, draw the tangent to the curve, then calculate its gradient

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## Collision Theory and Surface Area

- particles must collide with a certain minimum amount of energy, before they can react

- the minimum amount of energy the particles must have to react is called activation energy

- the rate of a chemical reaction inceases if the surface area to volume ratio of any solid reactants is increased, this increases the frequency of collisions between reacting particles

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## The Effect of Temperature

- reactions happen more quickly as the temperature increases

- increasing the temperature, increases the rate of reaction because particles collide more quickly and more frequently

- more of the collisions occuring in a given time results in a reaction because a higher proportion of particles have energy greater than the activation energy

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## The Effect of Concentration and Pressure

- increasing the concentration of reactants in solutions increases the frequency of collisions between particles

so increases the rate of reaction

- increasing the pressure of the reacting gases also increases the frequency of collisions

so increases the rate of reaction

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## The Effect of Catalysts

- a catalyst speeds up the rate of a chemical reaction, but is not used up itself during the reaction, it remains chemically unchanged

- different catalysts are needed for different reactions

- catalysts are used whenever possible in industry to increase rates of reaction and reduce energy costs

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