Investigating Rates of Reaction

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Investigating Rates of Reaction

AIM: To investigate the effect of concentration on rates of reaction using Sodium Thiosulphate and Hydrochloric Acid.

Sodium Thiosulphate + Hydrochloric Acid > Sodium Chloride solution + Sulphur Dioxide + Sulphur

Na O  > Na Cl + SO  + S

Hypothesis: The possible variables I could investigate could be:

  • Volume of liquid
  • Concentration of Sodium Thiosulphate
  • Concentration of Hydrochloric acid
  • Stir Quantity

I have chosen to vary the concentration of the Sodium Thiosulphate to see how his effects the rate of the reaction. I think that lowering the concentration of the Sodium Thiosulphate in the same volume of water will cause the reaction to slow dramatically. This is because of the collision theory.

The collision theory states that before a chemical reaction can take place the atoms, molecules or ions of a substance must collide. The more reactions that take place the faster the reaction. This is because when atoms, molecules or ions in a substance collide they speed up the reaction. More collisions allow the substance to react faster. Therefore when changing the concentration in the same amount of substance will mean there will be a greater or less chance of collision when you increase or decrease the concentration of Sodium Thiosulphate respectively.

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Increasing the concentration of a substance is basically increasing the amount of particles in a given volume. For example twice the concentration = twice as many particles. This means greater chance of collision and therefore a faster reaction.

Concentration= MASS

                        ________

                        

                        VOLUME

Concentration therefore will have a direct effect on my reaction as I will keep the volume constant but vary the mass of the Sodium Thiosulphate.

In conclusion I predict ...

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