Butanol:
Butanol + oxygen carbon dioxide + water
C4H9OH + 6O2 4CO2 + 5H2O
Octanol:
Octanol + oxygen carbon dioxide + water
C8H17OH + 12O2 8CO2 + 9H2O
All of these reactions are exothermic reaction. At the start of each reaction, less energy is taken in to break the bonds than is given out at the end of the reaction when new bonds are being made. More energy will be needed to break the bonds apart as we go down the list as there will be more bonds to break.
APPARATUS:
1) Thermometer
2) Stopwatch
3) Metal beaker
4) Copper tin
5) 100g water
PLAN:
1) Set up apparatus as shown in the diagram
2) In results table, write the start temperature of the water and the start mass of the
substance.
3) Light the substance at the wick.
-
When the temperature of the water in the metal beaker increases by 20° blow out the wick to stop the experiment.
- Write the end temperature down in your result table.
- Measure the substance and write down the mass at the end of the reaction in the result table.
- Repeat this 3 time.
8) Repeat step 1-7 for each substance.
Variables that stay the same:
Amount of water (100g)
Calculate energy per gram
Same increase in temperature.
APPARATUS:
1) Thermometer
2) Metal beaker
3) Copper tin
4) Substance
5) 100g water
RESULTS:
Energy released joules = temp increase x mass of water x specific heat capacity of water
Energy released = 20 x 100 x 4.2=8400j/g
Methanol
8400j = 5600j/g
1.5
Butanol
8400
- =5600j/g
Octanol
8400
- = 7636.36j/g
Propanol
8400
- =5250j/g
Ethanol
8400
1.2 =7000
CONCLUSION:
My results show that as the number of particles are increased, the energy transferred was also be increased.
EVALUATION:
I think that the test was not a fair test. There are a number of reasons for this:
- The copper can is metal. Metal is a good conductor of heat; therefore some of the heat released in this reaction would have been collected in the copper can.
- There was window close by to where we did the experiment. A draft could have come through and made a few results inaccurate.
- Not all-key variables were controlled i.e. “the same increase in temperature.”
To improve this experiment we could have closed the window so the draft could not interfere with our results. If this was controlled we would have got more accurate result. I think the apparatus we used was good enough for the experiment.