# Rates of Reactions

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## What is Rate?

Rate means the speed and can have many different units.

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## Measuring the rate of reaction

You can measure the rate of reaction by measuring the time taken for the metal to react.

The longer it takes the slower the reaction must be

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## How to measure the rate of reaction?

1. Measure the volume of gas made over a period of time. You have to measure how much is producted in a deligated time.

To get a clear indication of how much gas is being producted you need to use a gas syringe.

2. Measure the loss in mass over a period of time. All reaction that produce gass get lighter, as the gass escapes into the air.

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## Whats Activation energy?

The minimal amount of energy needed when materials collide together causing them to brake their old bonds and then form new ones.

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## What can you change to alter the rate of reaction?

• The Temperature
• The concentration
• The surface area
• Use a catalyst
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## Changing the surface area to alter the rate of rea

• The surface area is the area on the outside of the solid
• To make the reaction faster us smaller particles because there is a larger surface area, if you want to make the reaction slower us larger lumps of solid because there is a smaller surface area.
• Small particles mean a greater surface area.
• More collisions between particles and the other chemicals in the same amount of time
• More chance of a successful collision, increasing the rate
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## Changing the temperature to alter the rate of reac

The temperature measures how hot or cold the reaction is.

• Increase the temperature the particles have more energy
• They move quicker and collide more
• more collisions, more chance of successful collisions increasing the rate of reaction
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## Changing the concentration to alter the rate of re

The concentration states how much of the chemical is in a solution.

• the number of particles in a certain amount of space
• increasing the concentration of a chemical reaction means there are more particles in the same amount of time
• meaning more collision
• increase the rate of reaction
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## Using a catalyst to alter the rate of reaction

A catalyst is a chemical that speeds up a chemical reaction without being changed or used up itself.

• They are specific ( they only work for one reaction )
• different reactions need different catalysts
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