The Effect of Sodium Thiosulphate on the Rates of Reaction

The Effect of Sodium Thiosulphate on the Rates of Reaction

Introduction

In my experiment I will investigate how the rate of reaction of Sodium

Thiosulphate will be affected by the change in its concentration. But

before this I carried out a trail experiment to see which solution,

Sodium Thiosulphate or Hydrochloric acid would be more suitable.

My Trail Experiment Method was to first collect all of the equipment

needed, then I measured out the right amounts of each solution by

measuring from the bottom of the meniscus. Then I put the solutions

into a conical flask and timed how long it took for the paper cross

underneath the flask to disappear. I tested both solutions by changing

the concentration of one, then of the other but I kept the total

volume the same. I repeated the experiment again to make my results

more accurate, these were my results:

Volume of Sodium Thiosulphate

(cm3)

Volume of Hydrochloric Acid

(cm3)

Volume of Water

(cm3)

Time Taken

1st

(seconds)

Time Taken

2nd

(seconds)

Time Taken

Average

(seconds)

10

10

20

15

20

15

10

10

0

5

0

5

67

66

38

57

74

60

39

61

70.5

63.0

38.5

59.0

My Prediction

I predict that the more concentrated the Sodium Thiosulphate is the

quicker the reaction will take place. The less amount of Sodium

Thiosulphate and more amount of water the slower the reaction rate

will be. I know this because the scientific knowledge says that the

more molecules there are in the Sodium Thiosulphate the more chance of

a collision with the Hydrochloric Acid there will be. When the

molecules collide together a reaction takes place and once all the