The Effect of Concentration of Acid on the Rate of Reaction With Calcium Carbonate

The Effect of Concentration of Acid on the Rate of Reaction With Calcium Carbonate

Calcium + Hydrochloric ð Calcium + Carbon + Water

Carbonate Acid Chloride Dioxide

CaCO3 (s) + 2HCl (aq) ð CaCl2 (aq) + CO2 (g) + H2O (l)

Introduction

I will be using the reaction between calcium carbonate and

hydrochloric acid to see how the concentration of acid affects the

rate of a reaction. By doing the above experiment I will prove that

the higher the concentration of acid, the faster a reaction will

occur. I have carried out a previous experiment called the

'Disappearing Cross', in which I used the reaction between

thiosulphate, hydrochloric acid and water to see how concentration

affects the rate of reaction. When we added the hydrochloric acid to

the water and thiosulphate a reaction occurred, causing the water to

become foggy so that the cross was no longer visible through the

conical flask.

The results for the Disappearing Cross experiment were as follows;

Volume of Thiosulphate

(Cm3)

Volume of Water

(Cm3)

Volume of HCl

(Cm3)

Concentration

(%)

Time taken for X to disappear (seconds)

5

25

5

17

711

10

20

5

33

286

15

15

5

50

185

20

10

5

67

113

25

5

5

83

82

You can see that when the hydrochloric acid was most dilute the cross

took 711 seconds to disappear, and when the acid was most concentrated

the cross took just 82 seconds to disappear. This shows that the more

dilute the concentration of acid, the slower the rate of reaction and

the more concentrated the acid the faster the rate of reaction because

when acid is more concentrated there are more molecules, therefore

increasing the chance of a successful collision, and speeding up the