Prediction:
I predict that the more energy given out, the higher the number of moles.
Method:
Equipment:
- Ethanol in fuel burner
- Propan-1-ol in fuel burner
- Butan-1-ol in fuel burner
- Hexan-1-ol in fuel burner
- Octan-1-ol in fuel burner
- Heat proof mat
- 20ml water
- Boiling tube
- Clamp and stand
- Stop clock
- Measuring cylinder
- Splint/Matches (to light the burner)
First of all we completed a preliminary experiment to see what volume of water to use.
I will use a boiling tube to boil water in it. I will then use a clamp and stand to clamp the test tube at a certain height from the top of the burner. We will keep this height the same every time we do the experiment. We will also keep the amount of water, 20ml the same every time. We will take the temperature of water when it is not over heat at the beginning. I will measure the mass of the fuel at the beginning of the experiment and also at the end so we can tell how much fuel has been burnt. We will carry out the experiment for two minutes. When we start the stop clock, we will put the lighted fuel burner underneath the water filled test tube. We will stop the stop clock and remove the burner. We will take the temperature of the water again to take note of the temperature change. We will use these noted figures for chemical equations (taken into more consideration with results)
We will need to take these points into consideration to make the experiment a fair test:
1) keep the amount of water constant
2) keep the height from the bottom of the test tube to the top of the fuel burner constant
3) keep wind levels are the same
4) keep the wick length the same
We also had to take some safety regulations into consideration. For the girls hair had to be tied back. As we were using fuel burners, we had to stand up. Also, if something were to break, we were to tell the teacher straight away.
Diagram:
Results:
Energy given out = mass of water x constant (4.18) x average temperature
q = 20 x 4.18 x 24.67° = 2062.412
q = 20 x 4.18 x 39.50° = 3302.2
q = 20 x 4.18 x 13.67° = 1142.812
q = 20 x 4.18 x 12° = 1003.2
q = 20 x 4.18 x 17.67° = 1477.212
Number of moles = average mass ÷ Relative Molecular Mass
m = 0.63 ÷ 46 = 0.014
m = 0.77 ÷ 60 = 0.013
m = 0.35 ÷ 74 = 0.005
m = 0.26 ÷ 102 = 0.003
m = 0.18 ÷ 130 = 0.001
Conclusion:
My results prove that my prediction was correct. The higher the number of moles, the more energy given out.
Evaluation:
I should mention that I had to remove one line of results (highlighted above) as the mass change was an anomaly. I took these results out as I thought it would bring down my results. One of the days, when we were doing the experiment, we had to open the windows. We decided to use a wind shield to stop wind affecting the experiment. If we were to repeat the experiment, we would protect the flame from every direction so the heat loss would be less.
e.g.
Before After
Graph:
A graph to show the number of moles a fuel has compared to KJ/mole