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Investigating the Factors Influencing the Rate of Reaction Between Sodium Thiosulphate and Dilute Hydrochloric Acid

Satisfactory Essays
Investigating the Factors Influencing the Rate of Reaction Between Sodium Thiosulphate and Dilute Hydrochloric Acid

Introduction

In a reaction, the initial materials are called the products, and the

result materials are known as products. The time it takes for a

reaction to happen in is known as the speed or rate of the reaction.

The coursework entails investigating the rate of reaction between

Sodium Thiosulphate and Dilute Hydrochloric acid and the effect of

different variables on the reaction.

When a reaction between Sodium Thiosulphate and an acid, a cloudy,

yellow precipitate is formed. To see the time it takes a reaction to

occur there will be a measure of the time it takes for the precipitate

to occur. Looking through the conical flask with the Sodium

Thiosulphate and Hydrochloric acid solution, observing the 'X', until

it disappears, will do this. This is when the precipitate has formed.

The actual reaction in this experiment is:

Sodium thiosulphate + hydrochloric acid ==> sodium chloride + sulphur

dioxide + water + sulphur

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

There are a number of factors that alter the speed of chemical

reactions; these include temperature, concentration of reactions in

solution, pressure in gases, surface area, presence of light, and the

addition of catalysts. In the experiment that I will conduct, I will

vary the concentrations of the solution, whilst ensuring the rest of

the variables are kept constant. The dependant variable will be the

rate of the reaction or the time taken for a reaction to be present,

all other variables are fixed. Diluting the solutions with water will

vary the concentrations of Sodium Thiosulphate. The 8 different

concentrations will be: 1.0M 0.875M 0.75M 0.625M 0.5M 0.375M 0.25M

0.125M

Prediction

I predict that the higher the concentration of Sodium Thiosulphate,

then the higher the rate of reaction. I predict that the rate of

reaction is directly proportional to the concentration of Sodium

Thiosulphate. I predict that 1.0M of Sodium Thiosulphate will have the
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