[Justanotherstudent]

Hi, first of all sorry for any english mistakes I could make, it is a second language to me. 

I have a highschool chemistry homework and there is a problem that I'm very unsure how to solve. It goes like this :

''What quantity of energy is produced by the combustion of 3kg of propane?''

Any help would be greatly appreciated!! Thank you so much 

[Corribus]

The forum's policy is that you have to show your work to receive help. If you have no idea where to start, writing a balanced reaction is always a good first step.

[Justanotherstudent]

Oh. I didn't know that sorry.  Well I believe that the equation of the combustion of propane is :

C3h8 + 5O2 = 3Co2 + 4H20

I think I have to find the heat of the propane combustion first and it would be (according to my calculs, so still unsure) :

2,312kj/C° x 10,0 C° = -23,12KJ

then :

0,500/44,11 = 0,0113 mol

so :

? KJ/ 1mol = -23,12KJ/0,0113mol = 23,12 x 1mol/0,0113mol = -2046,02KJ

But then I'm totally lost, how do I integrate the 3kg factor in this equation? to find the energy produced.

[sjb]

Oh. I didn't know that sorry.  Well I believe that the equation of the combustion of propane is :

C₃H₈ + 5O₂  3CO₂ + 4H₂O

I think I have to find the heat of the propane combustion first and it would be (according to my calculs, so still unsure) :

2,312 kJ/C° x 10,0 C° = -23,12 kJ ...

Where has the 2312 kJ/C° figure come from?