To Find Out How Much Energy Is Given Out by Methanol, Ethanol,Propanol, Pentanol and Butanol.

Propanol - C3H7OH

C3H7OH + 4 1/2 O2 3CO2 + 4H2O

2 x C - C 2 x 350 = 700

7 x C - H 7 x 410 = 2870

x C - O 1 x 360 = 360

x O - H 1 x 460 = 460

4 1/2 x O=O 4 1/2 x 496 = 2232 +

6622kj

6 x C=O 6 x 740 = 4440

8 x O - H 8 x 460 = 3680 +

8120kj

6622 - 8120 = -1498kj

Butanol - C4H9OH

C4H9OH + 6O2 4CO2 + 5H2O

3 x C - C 3 x 350 = 1050

9 x C - H 9 x 410 = 3690

x C - O 1 x 360 = 360

x O - H 1 x 460 = 460

6 x O=O 6 x 496 = 2976 +

8536kj

8 x C=O 8 x 740 = 5920

0 x O-H 10 x 460 = 4600 +

10520kj

8536 - 10520 = -1984kj

Pentanol - C5H11OH

C5H11OH + 7 1/2 O2 5CO2 + 6H2O

4 x C - C 4 x 350 = 1400

1 x C - H 11 x 410 = 4510

x C - O 1 x 360 = 360

x O - H 1 x 460 = 460

7 1/2 x O=O 7 1/2 x 496 = 3720 +

10450kj

0 x C=O 10 x 740 = 7400

2 x O-H 12 x 460 = 5520 +

12920kj

0450 - 12920 = -2470kj

Apparatus

* Two clamps

* Clamp stand

* Thermometer

* Copper can

* Spirit burner

Spirits

. Methanol

2. Ethanol

3. Propanol

4. Butanol

5. Pentanol

* Measuring cylinder

* Digital scales

* Splint

Method

Firstly attach the clamps onto the clamp stand, and then to the top clamp, attach the thermometer allowing the thermometer readings to be visible. Fill the copper can with 100cm3 of water and attach the copper can to the bottom clamp. Move the copper can up so the end of the thermometer is about 1cm away from the bottom of the copper can. The thermometer must not touch the copper can, only the water.

Weigh the first spirit burner with the first fuel on the digital scales, leaving the spirit burner lid on, so there is no loss of fuel by evaporation, and record the weight. Place the first spirit burner under the copper can leaving a 1cm gap between the end of the wick and the copper can. Measure the temperature of the water and record the result.

Light the spirit burner, using a flint. Once the temperature has raised 10ºC put out the flame by placing the cap on the top of the spirit burner. Measure the weight of the spirit burner with the lid still on and record the result.

Repeat twice for each fuel. Then work out how much energy is needed to make and break the bonds.

Diagram

Thermometer Clamp

Burner Copper can

Spirit burner

Clamp stand

Results

Fuel

Weight before in g

Weight after

in g

Temperature of water before ºC

Temperature of water after ºC

Ethanol

79.8

79.3

21

33

Methanol

59.2

58.8

21

30

Butanol

65.1

64.9

21

31

Pentanol

75.5

75.3

22

31

Propanol

67.2

66.9

21

32

a) Temp rise x 100cm3 x 4.2 = how much energy is given out in kj.

b) Energy given out in kj / difference in weight in g = How much energy given out per g.

Methanol

a) 9 x 100 x 4.2 = 3780kj

b) 3780kj / 0.4g = 9450g

Ethanol

a) 12 x 100 x 4.2 = 5040kj

b) 5040kj / 0.5g = 10080g

Propanol

a) 11 x 100 x 4.2 = 4620kj

b) 4620kj / 0.3g = 15400g

Butanol

a) 10 x 100 x 4.2 = 4200kj

b) 4200kj / 0.2 = 21000g

Pentanol

a) 9 x 100 x 4.2 = 3780kj

b) 3780kj / 0.2g = 3779.8g

Conclusion

I was right in saying that the more carbon atoms there are, the more energy is required to break the bonds. I can prove this because Pentanol has the most carbon atoms, and when it is burnt it gives out the most amount of energy.

Methanol gives out the least amount of energy because it has the least number of carbon atoms in it.

The order of how much energy each fuel gives of.

. The most, 5. The least:

. Pentanol

2. Butanol

3. Propanol

4. Ethanol

5. Methanol

Evaluation

To improve the way I carried out the experiment I could have repeated the experiment more than once. You could also use a Bomb Calorimeter, so water is completely surrounding the flame and no energy is given off.

As the water is being heated you could use a stirrer so the all the water would be the same temperature, and not different in parts.

If I pumped oxygen through the Bomb Calorimeter under the water where the flame is, the flame would burn to its full potential.

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