Chemistry Coursework - Rate of Reaction

which affect the experiment.

Variables

In this investigation I will be using the variable concentration of

chemicals used in the experiment. The variables listed above will

affect the experiment in some way.

· Temperature

The temperature also affects the rate of reaction because all the

atoms have a certain amount of energy to successfully collide with

other atoms of a different type. If you heat these atoms however the

atoms gain energy that speeds them up results in the atoms colliding

quicker and harder into each other making the reaction quicker. The

higher the temperature the faster the reaction will take until a

certain temperature when compared to a lower temperature of the same

concentration.

· Concentration

The concentration of the chemicals dissolved in water effects the rate

of reaction because the atoms of the Sodium Thiosulphate and

Hydrochloric acid need a certain amount of energy to collide with each

other successfully to create a new chemical via a displacement

reaction. If the concentration of one of the compounds is increased

the reaction will be quicker if the temperature is the same because

there are more atoms of one type to collide successfully with the

other compound, resulting in the reaction being quicker when compared

to a reaction with lower concentrations of the compounds dissolved

into water.

· Catalysts

Catalysts can speed up a chemical reaction because they reduce the

amount of energy needed to have a successful collision and they are

never used up and remain exactly the same at the end of the experiment

as they were at the start.

Prediction

I predict that as the concentration of the Sodium Thiosulphate

increases the reaction between the Sodium Thiosulphate and the

Hydrochloric Acid will be quicker when compared to a lower

concentration if the Hydrochloric Acid has the same concentration in

both experiments and the temperature stays the same throughout. This

is because the atoms of the Sodium Thiosulphate and Hydrochloric acid

need a certain amount of energy to collide with each other

successfully to create a new chemicals. If the concentration of one of

the compounds is increased the reaction will be quicker if the

temperature is the same because there are more atoms of one type to

collide successfully with the other compound, resulting in the

reaction being quicker when compared to a reaction with lower

concentrations of the compounds dissolved into water.

I will set up the apparatus as shown on a past page and have a

table ready to record the information from the investigation onto. I

will test each different concentrations five times of Sodium

Thiosulphate, ranging from 50cm^3 to 10cm^3 going down by 10cm^3 at

regular intervals with the 5cm^3 of Hydrochloric Acid and start to

time how long it takes for the compounds to react and form a cloudy

solution which will prevent me form viewing the cross underneath the

conical flask when two compounds first touch each other. I will then

stop the timer and record the results of the experiment and start the

next test. After I have collected all my results I will find out the

average for each concentration of Sodium Thiosulphate to react with

Hydrochloric Acid.

Results

Run

Vol Na2S203 cm3

Vol HCL cm3

Vol H2O cm3

Time Taken (s)

Rate (1/time)

1

50

5

0

25

0.040

2

40

5

10

32

0.031

3

30

5

20

42

0.024

4

20

5

30

64

0.016

5

10

5

40

172

0.006

Conclusion

From my results I have gathered I have concluded that as the

concentration of Sodium Thiosulphate decreases the experiment takes

longer to finish. This is because there are less Sodium Thiosulphate

atoms to collide successfully with the Hydrochloric Acid resulting in

the experiment taking longer which the results do show. The prediction

I created earlier on, before the experiments were carried out is

proved correct by my results that I have collected.

Evaluation

The investigation has gone very smoothly with the results being

accurate to certain degree from reacting the Sodium Thiosulphate with

the Hydrochloric Acid, which has left myself being able to appear with

a firm conclusion from the results I have gathered. I don't think I

could of improved the experiment because their wasn't anything that

went wrong but I could of done another variable to appear with an even

stronger conclusion, if my predictions for the additional variables

were correct with my results.

References

Visible links

Hidden links:

1. http://www.coursework.info/