Rates of Reaction.

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Rates of Reaction

Aim

I will be investigating the rate of reaction (how quick a reaction

takes) of Sodium Thiosulphate (Na2S2O3) and Hydrochloric Acid (HCl

{aq}). There are different variables that can affect the rate of

reaction. The different variables include Temperature, catalysts and

concentration. In this piece of coursework, I'll be analysing the

concentration.

The products we get are

Sodium Thiosulphate + Hydrochloric Acid --> Sodium Chloride + Water + Sulphur dioxide

Na2S2O3 (aq) + 2HCl (aq)--> 2NaCl (aq) + H2O (l) + SO2 (g) + S (s)

Apparatus

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1 Eye protection

2 measuring cylinders

1 White paper with bold black cross

1 Stopwatch

1 beaker (50ml)

Sodium Thiosulphate (0.2m)

Hydrochloric Acid (0.2m, 0.4m, 0.6m, 0.8m, 1m)

Prediction

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In my prediction I presume that if the concentration of Hydrochloric

Acid is increased, the faster the rate of reaction. The reason is

because of the collision theory. The collision theory is linked to all

the different variables that affect the rate of reaction. For a

reaction to occur particles need to collide with each other.

Unfortunately, only a small percent of particles collide to result in

a reaction. This is due to the particles overcoming the energy

barrier. The barrier is the activation energy or Ea. Particles need a

certain amount of energy to pass this barrier to successfully create a

reaction. For particles to get energy you can increase the temperature

to allow the particles to overcome this barrier. The activation energy

size depends on each sort of reaction.

Now the activation energy barrier has been passed, the percent of

successful collisions does not change. For this to change it now

depends on the different variables that affect the rate of reaction.

Concentration

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When you increase the concentration this increases the amount of the

reactant particles per unit volume. Therefore there will be a higher

chance of the particles colliding with the opposing particles to

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