[llain123]

Well I've mastered the main part of Hess's law, but when I'm asked to form the equation for the formation of a compound myself, I don't know what to do.

Eg. Formation of C₂H₄, formation of ethanoic acid and more complex ones.

To take the first as an example, how do I know if its:

2C+2H₂ -> C₂H₄

or

C₂+2H₂ -> C₂H₄.

Don't even know where to start for ethanoic acid.

Thanks!

[darko]

as a start you have to learn what is represente with 2C and what with C₂, wich dont exist (on the level of chemistry you are involved), as a help gasses (except nobel gasess), are in molecular shape ig N₂,O₂  ,and "other" compounds are in atomic state (there are few wich is important for you to know which are exceptions P₄, S₈...), and thuse are represented as ig: C, Ca, Pb, K, Na....

so 2C means two atoms of carbon, N₂ means one molecule oh nytrogen (consisted of two atoms).

hope it helps

p.s. terms are used on the level of knowledge acorded to the question, formation of acetic acid is not the most educational (may get in several ways) in field of Hess law, it is more organic mechanisams.

[SirRoderick]

As for CH3COOH, just use H2, C and O2

[llain123]

as a start you have to learn what is represente with 2C and what with C₂, wich dont exist (on the level of chemistry you are involved), as a help gasses (except nobel gasess), are in molecular shape ig N₂,O₂  ,and "other" compounds are in atomic state (there are few wich is important for you to know which are exceptions P₄, S₈...), and thuse are represented as ig: C, Ca, Pb, K, Na....

so 2C means two atoms of carbon, N₂ means one molecule oh nytrogen (consisted of two atoms).

hope it helps

p.s. terms are used on the level of knowledge acorded to the question, formation of acetic acid is not the most educational (may get in several ways) in field of Hess law, it is more organic mechanisams.

Thanks. I understand the difference between 2C and C₂, but I didn't know which state carbon would be in. It seems there are certain standards for these like you mentioned with gases so I'll try and find out what they all are.

As for CH3COOH, just use H2, C and O2

Gotcha, thanks.