In this investigation, I aim to find out how temperature affects the rate of reaction between hydrochloric acid and magnesium ribbon.

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Rates of Reaction

Aim:

In this investigation, I aim to find out how temperature affects the rate of reaction between hydrochloric acid and magnesium ribbon.

Introduction:

In solids, liquids and in a solution, the particles move constantly but at different speeds to each other. Some particles are moving faster or slower than others are. But for a chemical reaction to occur the bonds in the reactants have to be broken. They are broken by the collisions between particles. The successful collisions are those that have enough energy to break these bonds. This “minimum amount of energy needed to break the bonds” is known as the activation energy.

As more and more collisions occur, the more successful collisions there are going to be. These successful collisions affect the rate of reaction as in it is increased. So the fewer collisions there between particles the fewer successful collisions there are. This leads to a slower rate of reaction. 

When Hydrochloric acid and Magnesium are placed together, a reaction occurs. Here is a word equation for the reaction:

Magnesium        +   Hydrochloric acid                          Magnesium Chloride   +    Hydrogen.

Here is a balanced symbol equation for the reaction above:

Mg                +            2HCl                        MgCl₂                +                H₂

The reaction between HCL and Mg occurs using the collision theory I explained earlier. However the rate of this reaction is affected by various factors as listed below:

  • Concentration
  • Surface area and particle size
  • Temperature
  • Catalyst

I shall now explain how these factors affect the rate of a chemical reaction and particularly the reaction of HCl and Mg.

If you increase the concentration of reactants as in HCl this means that there are more particles in the same volume. If there are more particles this means that there will be more collisions between particles. As more collisions happen there obviously will be more successful collisions. This increase in number of successful collisions leads to a quicker rate of reaction. So if the concentration is decreased the number of particles for a given volume decreases too. Fewer particles means that there are fewer collisions. And therefore there would be fewer successful collisions between particles of reactant. Overall this means that there would be a slower rate of reaction.

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Surface area also affects the rate of reaction. Large chips/solids of the Magnesium means that they will have a smaller surface area. A smaller surface reduces the chances of particles at show reacting. So there are fewer particles at show to react. This means that there would be fewer successful collisions and a slower rate of reaction. Whereas if powdered Magnesium was used in the reaction with Hydrochloric acid then the surface area would increase. More surface area means that there are more particles at show to react with. The more particles there are the ...

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