Question

Question below.

I think it's a? am I right?
because i don't have to reverse the other eqn or else everything will cancel out..

Answer 1

you have to reverse the first eqn, so it's solid -> gas

Answer 2

so it's c?
but why it should be solid to gas? for the reaction to be spontaneous?

Answer 3

because it's asking for the enthalpy change when sublimation occurs, sublimation is the process when a solid goes into the gas phase (skips liquid)

Answer 4

oh yeah that makes sense... thanks!

Answer 5

np!