HELP exam in 2 days and still don't get Hess' cycle!

Ahghghgh
I'm so nervous I thought i understood it but it seems that I still didn't fully grasp th concept. I'm attaching the question that i was confused with.
My questions:
-Why is there 2.5 infront of H2 for the bottom equation? Shouldnt it be just 1/2 instead because the coefficient of HCl is 1?

Please explain to me how the directions of the arrows are determined. Lke why the arrow towards C2H5CL is upwards not downwards?

Actually please tell me how to get this annoying hess' cycle right inside out...

Please help

Have a look here, it's a helpful site: http://www.chemguide.co.uk/physical/energetics/sums.html .

As to the question you've posed, I think the 2.5 relates to the number of bonds actually broken rather than going through the rigmarole of calculating the breaking and reforming every single bond, could be wrong though - haven;t done Hess' Law in a good while.

I'd say the direction of the arrows is dictated by bonds being formed and broken. So, bonds broken requires energy input so it'll be endothermic.

Hope that helps in some way, if not - at least I've bumped for you.

5 Hydrogens part on top left. Hydrogen is a diatomic molecule. So 2.5 molecules.