Question

11. Which one of the following is a correct formation reaction?
A. C(diamond) → C(graphite)
B. H2(g) + O(g) → H2O(l)
C. C(graphite) + 4H(g) → CH4(g)
D. 6C(graphite) + 6H2O(s) → C6H12O6(s)
E. 2C(graphite) + 3H2(g) + ½O2(g) → C2H5OH(l)

According to my answer key the answer is E. Can anyone explain why?

Answer 1

@Delta9991

Answer 2

any ideas?

Answer 3

hmmm.... I'm really not sure. It's been a few years since I took chem here at school. I'll look into it

Answer 4

Ok, from what I can tell... it appears to be the lowest legal way for a molecule to form (i'll explain that). A is just a change of crystal structure, not a change in the molecule (be it diamond or graphite, its still carbon). H2 +O doesn't work because the only time you find O is as O2. That would mean for that to be a correct formation reaction, it'd have to be 1/2 O2. Same for answer C, you only come across H2 in nature, not H. Letter D doesn't work as It already has H2O formed for you. As such, that only leaves E. Kinda make some sense?

Answer 5

Basically, break the whole thing down to its most basic components, each individual atom. Then, write that as you would find it in nature (eg. 1/2 O2 instead of O and the sort).

Answer 6

Oh okay, you want all the reactants in their standard state I think. Thanks!

Answer 7

yeah, sorry I dont remember much terminology, glad i could help!