Question

The equation shows one mole of ethanol fuel being burned in oxygen. Convert the energy
released into its equivalent mass.
C2H5OH(l) + 3 O2(g) Æ 2 CO2(g) + 3 H2O (l) ΔH = -1418 kJ/mol

Answer 1

Well sense we are doing an combustion we assume that the only work done on the system is volume work and we can write up the following:
ΔU=q+w

w=0

q=ΔH

Here is U, the internal energy, q the process of heat, w the process of work and delta H the change in entropy.
We can here use Einstein's relation between mass and energy:
E=mc2

We isolate for the mass, m;
m=Ec2

Where:
E=ΔU=ΔH
..........Hope it helps.............