the question would be like "identify one natural resource (which would be other than fossil fuels obviously) that is shrinking/depleting (or sumthin like that) and identify alternatives to this source." lol thats probably the most badly worded question in the world.. but u get my drift, at least...
if they give u the energy (eg. energy released by this thingo is 200kJ), you have to multiply it ('it' being the energy in kJ) by the number of moles of fuel burnt. So (delta)H= energy * moles of fuel burnt. Whatever answer you get is the enthalpy, which is (delta)H. And then you can use the...