When coal is mined, it is tested for how much heat it can produce when it burns. A 1.245g sample of coal was placed into a calorimeter containing 2000.0 mLs of water at 17.5 degrees Celsius. After the coal was combusted in the calorimeter, the water's temperature was found to be 24.7 degrees Celsius.
a)How many Joules (J) of heat were produced by the burning of this coal sample? I got 60,249.6J is that correct?
b)How much heat would 1.00 kg of this coal produce? I got 48,393,253.01 again is that right?
c)How many BTU's/pound would this coal produce? 1 Joule = 9.5 x 10 to the -4 BTU of heat. (A BTU is a British Thermal Unit) There are 453.6 grams in 1 pound. This I am completely stuck on please help.
heat=masswater*c*changeInTemp
= 2kg*4.18kJ/kgC*7.2C which is your answer in a)
I agree with Bob P but your answer, with that many significant figures, could be counted wrong.
b. is right. Same comment about s.f.
a) To calculate the amount of heat produced by the burning coal sample, we can use the formula:
q = mcΔT
Where:
q = heat (in joules)
m = mass of water (in grams)
c = specific heat capacity of water (4.18 J/g°C)
ΔT = change in temperature (in °C)
Given data:
Mass of water (m) = 2000.0 g
Change in temperature (ΔT) = (24.7 °C - 17.5 °C) = 7.2 °C
Plugging in the values:
q = (2000.0 g) * (4.18 J/g°C) * (7.2 °C)
q = 59,616 J
So, the correct answer for part (a) is 59,616 J, not 60,249.6 J.
b) To calculate the amount of heat produced by 1.00 kg (1000.0 g) of coal, we can use the following equation:
Heat produced by 1 kg of coal = Heat produced by the sample * (1000.0 g / 1.245 g)
Plugging in the values:
Heat produced by 1 kg of coal = 59,616 J * (1000.0 g / 1.245 g)
Heat produced by 1 kg of coal = 47,910,843.69 J
Therefore, the correct answer for part (b) is 47,910,843.69 J, not 48,393,253.01 J.
c) To calculate the amount of BTUs (British Thermal Units) produced per pound of coal, we need to convert the heat produced in joules to BTUs. Given that 1 J = 9.5 x 10^-4 BTU, we can use the following equation:
Heat produced in BTUs = Heat produced in joules * (1 BTU / 9.5 x 10^-4 J)
Now, we need to convert grams to pounds. Given that there are 453.6 grams in 1 pound, we can use the following equation:
Heat produced in BTUs/pound = Heat produced in BTUs / (mass of coal in grams / 453.6 g/lb)
We have already calculated the heat produced in joules as 59,616 J. Let's plug in the values:
Heat produced in BTUs = 59,616 J * (1 BTU / 9.5 x 10^-4 J)
Heat produced in BTUs = 62,754,736 BTU
Heat produced in BTUs/pound = 62,754,736 BTU / (1.245 g / 453.6 g/lb)
Heat produced in BTUs/pound = 2,136,820.34 BTU/lb
Therefore, the correct answer for part (c) is 2,136,820.34 BTU/pound.