An Investigation of the Effect of Concentration Change On the Rate of the Reaction Between Magnesium and Hydrochloric Acid.

How to mix up a different concentration solution?

The concentration of hydrochloric acid will change when water is added into it. The ratio is in proportion. That means more water is mixed with the acid, the concentration of the solution will be low.

Sugar concentration (M)

Volume of water (ml)

Volume of sugar (ml)

0

20

0

0.1

8

2

0.2

6

4

0.3

4

6

0.4

2

8

0.5

0

0

0.6

8

2

0.7

6

4

0.8

4

6

0.9

2

8

0

20

After I have finished the test run, I will do my real experiment.

Method

. I have set 7 different concentration of hydrochloric acid

2. I will also use 3 states of magnesium, ribbon, large chips and small chips, to see if there are any influences on the timing if different states of magnesium are used.

3. I will do 7 different concentrations, so that I need 7 magnesium ribbons, 7 large chips and 7 small chips.

4. I will measure all the magnesium ribbon, turning and powder with a balance to make sure that they have the same weight.

5. Set up the apparatus as below.

6. I will put the hydrochloric acid in the side-armed tube

7. I will put the magnesium in the small tube without getting touch with the hydrochloric acid.

8. I will move the tube, so the acid can react with the magnesium.

9. Use a stopwatch to count the time.

Mark down the volume of gas in every 15 seconds.

10. Wait until the reaction goes to 7 minutes.

11. Plot the result in the table.

12. Draw a graph according to the result.

Safety Caution

1. Be careful when using the glassware eg. Tubes and beakers.

2. Be careful when using the hydrochloric acid, it can be harmful when get into the eyes.

3. Wear safety spectacles to protect your eyes.

4. Wear laboratory coat when you are doing the experiment.

Fair test

1. Same amount of magnesium in every sample.

2. The measurement of the solution should be accurate.

Apparatus list

. Magnesium ( ribbon, turning, powder )

2. Hydrochloric acid

3. Water

4. Balance

5. Scissors

6. Micro test tube

7. Side-arm test tube

8. Measuring cylinder ( 10 ml and 250 ml )

9. Box ( to contain water )

Variables

1. Concentration

Increasing the concentration of reactants increases the rate of a reaction. This is because there are more particles in the same volume so more collisions are possible every second

2. Temperature

Temperature will also influence the result of the experiment. This is because the temperature (heat) gives energy to the chemicals. At the higher temperature, the reactant particles move faster and collide more often and more violently.

3. Surface area

The surface area of the chemicals will also change the result of the test. Breaking up the chemical into small pieces increase the reaction rate because the increasing surface area will increase the number of particles of the chemical in contact with other reactant in the solution.

4. Catalyst

Catalyst increases the number of collision; it works by giving a platform for the reacting particles to stick to, so that they can collide each other easier. In this way, the number of collision increases.

Catalysts are not used up in the reaction.

Amongst the four factors, I will choose concentration and surface area to do my experiment.

Prediction

* The volume of gas

Concentration

I predicted that more gases will be produced in a higher acid concentration because there will be more particles in hydrochloric acid for the magnesium to collide

In the other hand, there will be less gas produced in a low acid concentration sample because there are fewer particles for the magnesium to collide.

Surface area

Magnesium ribbon

There is least surface area amongst them, so the rate of the gas produced is the slower.

Magnesium turning

There are more surface areas in the turning so that more hydrochloric acid can collide with the magnesium, the reaction is more violent and the rate of producing gas is faster.

Magnesium powder

The magnesium powder has the largest surface area so that the acid can react with the magnesium easily. The reaction is the most violent and the largest amount of gas is produced.

I have done some experiments in the past can support my prediction.

Concentration

If the solution is more concentrated, it means that there are more particles knocking each other, which will cause more collisions.

I have done a test on reaction with different concentration in the previous experiment. It is the reaction between sodium thiosulphate and dilute hydrochloric acid.

In the experiment, I will draw a cross on a piece of filter paper and place a 100cc beaker on the paper so that we can see the cross through the beaker.

i mix the sodium thiosulphate with water at a volume of 50cc, then i will add 5cc of hydrochloric acid in the beaker.

the solution will change to milky and i will record the time it takes to cover the cross. I will increase the amount of water in the other experiment to see if there is any difference.

I will set 5 concentrations.

Experiment

Volume of sodium thiosulphate (cc)

Volume of water

(cc)

Volume of hydrochloric acid

(cc)

Time for the cross to disappear

(s)

50

0

5

27

2

40

0

5

37

3

30

20

5

56

4

20

30

5

82

5

0

40

5

75

Reaction rate = 1/time

Experiment

Concentration of the sodium thiosulphate(unit)

reaction rate

0

2

8

3

6

4

4

5

2

The volume of gas produced in the reaction between magnesium ribbon and different concentration of hydrochloric acid

Time

(s)

Volume of gas in 0 M

(water)

Volume of gas in

0.2M

Volume of gas in

0.4M

Volume of gas in

0.5M

Volume of gas in

0.6M

Volume of gas in

0.8M

Volume of gas in

M

0

0

0

0

0

0

0

0

5

0

0

3

4

6

6

7

30

0

7

0

1

2

5

45

0

2

1

5

6

9

24

60 1min

0

3

5

8

21

28

32

75

0

4

9

22

26

36

39

90

0

4

22

26

31

44

47

05

0

6

25

29

36

51

55

20 2min

0

7

29

32

40

57

61

35

0

9

32

34

44

62

67

50

0

0

34

36

47

67

73

65

0

1

36

39

51

71

79

80 3min

0

1

37

42

54

74

85

95

0

2

39

43

56

77

90

210

0

3

40

45

59

80

94

225

0

4

41

47

61

83

98

240 4min

0

4

41

49

63

86

03

255

0

5

42

51

65

89

07

270

0

7

43

53

66

92

11

285

0

8

44

55

68

94

14

300 5min

0

8

44

56

70

95

17

315

0

9

45

57

71

96

18

330

0

9

46

59

73

97

18

345

0

9

46

61

74

98

19

360 6min

0

20

47

61

74

98

19

375

0

21

48

62

75

99

20

390

0

22

48

63

76

00

20

405

0

23

49

64

76

00

20

420 7min

0

24

50

64

76

00

20

7