a) CH2O
each element can be divided by 2
b) BCl3
the molecule is already in it's empirical formula
c) CH4
the molecule is already in it's empirical formula
d)CH2O
each element can be divided by 6
-63.79 kJ/g
Explanation:
According to the law of conservation of energy, the sum of the heat released by the combustion of the new organic material (Qcomb) and the heat absorbed by the bomb calorimeter (Qbc) is zero.
Qcomb + Qbc = 0
Qcomb = -Qbc [1]
We can calculate the heat absorbed by the bomb calorimeter using the following expression.
Qbc = C × ΔT
where,
C: calorimeter constantΔT: change in the temperatureQbc = C × ΔT
Qbc = 28.81 kJ/°C × (30.28°C - 24.91°C) = 154.7 kJ
From [1],
Qcomb = -154.7 kJ
The heat of combustion per gram of the material is:
-154.7 kJ / 2.425 g = -63.79 kJ/g