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Energy released when during the burning of a nut?
I have to design and complete a chemisrty investigation which compares the heating value of two nuts, on a per gram basis. (In other words, find which nut releases the mose energy when burnt). I have been looking for a formua or experiment which will let me do this but im having trouble finding anything. Any help would be greatly appreciated.
Answer: One way to do this is to measure how much the nuts when combusted raises the temperature of a set amount of water.
It takes 1 Calorie= 4.19 Joules to raise the temperature of 1 mL of water (1g) 1 degree Centigrade (ËšC).
So use a set amount of water (probably something relatively small) in a beaker or test tube with a thermometer (digital give faster more precise results, however a generic one will do). Record initial temperature of the water. Weigh nut A (in grams) and record. Light nut A and place it under the contain of the water. Record final temperature.
Repeat using the same amount of water with the same steps, but insert nut B instead.
Example for calculation per gram basis:
Nut A = 7.00 grams
Water = 5.00 mL
Initial Temp = 20.0ËšC
Final Temp = 32.0ËšC
Change = 12.0ËšC
As we know 1 Calorie raises 1 mL of water 1ËšC so:
12.0ËšC x (1 Calorie/1ËšC) = 12.0 Calories or 50.3 Joules
Thats the energy required for 1 mL water, but in this case you have 5 times that, 5 mL of water.
12.0 x 5 = 60 Calories
50.3 x 5 = 252 Joules
So your 7.00g Nut provided 60.0 Calories of energy or 252 Joules. In terms of per gram:
60.0 Calories/ 7.00 grams = 8.57 Calories per gram
252 Joules/ 7.00 grams = 36.0 Joules per gram
*Note* I took the liberty of providing the answers in the sample calculations using significant figures.
Now just do the same for Nut B and you have the two answers by gram and you can then compare the results.
This method is not the most accurate, however, for a school project it should be accurate enough. Not to mention is it pretty easy to set up and clean up is easy.
