Risk Assessment
Chance of water/ alcohol Wear goggles
Spraying in eyes
Burned Hair Tie hair up
Setting Bench on fire Use bench mat
I will do each experiment twice to make sure the results are reliable and I can do some averages.
The equipment I will need to do this experiment is:
- Clamp
- Boss
- Stand
- Tin with water
- Thermometer
- Bench mat
- Alcohol (methanol, Ethanol, Butanol and Propanol)
Here is a diagram of the apparatus:
The variables that have to be kept constant through out the experiment are:
-
Mass of water (1200C)
- Distance from fuel to tin (any distance, measure and keep the same)
-
Temperature to reach while heating fuel (450C)
The variable to be changed is:
My prediction for this experiment is:
I think that Butanol will give out more energy than the other alcohols because it has more hydrocarbons and bonds making the structure larger, which I think will affect the amount of energy given out.
1st set of results
2nd set of results
I will now work out the average for all the alcohols including the difference.
The reaction taking place through the experiment is an exothermic reaction meaning that it gives out energy.
This graph shows how much weight is lost after burning each alcohol.
This graph shows the difference between the before and after weight.
The equation for working out energy absorbed by can is:
Energy absorbed=amount of water (g) x temperature rise (oC) x Specific Heat Capacity 4.18 (jg-1 0C-1)
Energy absorbed=120 x 25 x 4.18 = 12540J
Now to work out how much energy is given out, I will divide this number by each average difference for each type of alcohol.
This shows how much energy is given out. I will now to a graph showing the end results.
The graph shoes that Butanol had given out the most energy.
I will now find out how much energy is given out in a mole.
Energy Released In A Mole
Butanol (From Periodic Table)
H=1
C=12 (10x1) + (4x12) + 16= 74g per mole
O=16
Propanol
H=1
C=12 (8x1) + (3x12) + 16= 60g per mole
O=16
Methanol
H=1
C=12 (4x1) + 12 + 16= 32g per mole
O=16
Ethanol
H=1
C=12 (6x1) + (2x12) + 16= 46g per mole
O=16
Evaluation
The results I achieved from this experiment were reliable, but there are some ways I could have improved the experiment to get better results.
- There were a few windows open making the flame go out a few times, I shut them during the experiment. But if I was going to do the experiment again I would make sure all of the windows were shut to start with.
- The wicks of all the alcohols had different lengths making some of the flames closer to the bottom of the tin.
Another way of improving the experiment is to insulate the sides of the tin or cover the top to stop heat loss.