Investigating the Effect of Concentration on the Speed of the Reaction Between Hydrochloric Acid and Sodium Thiosulphate

Investigating the Effect of Concentration on the Speed of the Reaction Between Hydrochloric Acid and Sodium Thiosulphate

Prediction:

My prediction is, the higher the concentrations, the faster the

reaction will occur in my experiment to make the x on the sheet on

paper disappear. When there is more concentration, the molecules gain

kinetic energy & the process of collision occurs. This causes the

reaction to happen more rapidly therefore making a cloudy substance

much quicker.

Hypothesis

Sodium thiosulphate has the formula Na2S2O3. It resembles sodium

thiosulphate, Na2SO4, with one less oxygen atom and one more sulphur

atom. The additional sulphur atoms can be driven out by an acid.

Equation

[IMAGE]Na2S2O3 + 2HCl

S + 2NaCl + SO2

Sodium

[IMAGE]Thiosulphate + Hydrochloric acid Sulphur + sodium

chloride + sulphur dioxide

Variables

Independent Variable - factors to be changed:

The concentration of sodium thiosulphate solution will be adjusted to

be tested at different molars. This is changing the ratio of sodium

thiosulphate to water.

Dependant variable - factor to be measured:

The time it takes for the cross to be fully out of vision will be

measured to test the rate in which acid reacts with thiosulphate. This

will be done by using a stop clock.

Molar Concentration

Molar Concentration

Volume of sodium thiosulphate solution in cm cube

Volume of Water in cm Cube

1.0

50

0

0.8

40

10

0.6

30

20

0.4

20

30