AS energetics help

Does anyone know if this is an exothermic or endothermic reaction and explain why?
(sorry about the no subscript numbers - dont know how to do it on here)

C02(g) + 2H2O(g) = CH4(g) + 2O2(g)

Iv only started this topic today at school so can you try and explain as simply as possible - Thanks!!

X

Reply 1

Artymess

16

ooh good question, i'm reckoning the forward equation is endothermic, co2 and h2o are fairly stable molecules so you'd have to put a lot of energy in to break the bonds. that and the backwards reaction is the combustion of methane, which if im not mistaken is an exothermic reaction.

someone feel free to correct if wrong :smile:

Reply 2

Kyri

15

Artymess

ooh good question, i'm reckoning the forward equation is endothermic, co2 and h2o are fairly stable molecules so you'd have to put a lot of energy in to break the bonds. that and the backwards reaction is the combustion of methane, which if im not mistaken is an exothermic reaction.

someone feel free to correct if wrong :smile:

Sounds good to me :smile:

. I come up with the exact same reasoning. I think you're mainly supposed to be able to tell by the fact the backwards reaction is the complete combustion of a hydrocarbon which is always exothermic.