endothermic or exothermic?

Question

C2H5OH(l) → C2H5OH(g)

Br2(l) → Br2(s)

C5H12(g) + 8O2(g) → 5CO2(g) + 6H2O(l)

NH3(g) → NH3(l)

NaCl(s) → NaCl(l)

Answer 1

Think about this ...

to change a liquid into a gas, do you add heat or remove heat? You would ADD heat, right? So that would be an ENDOTHERMIC reaction.

to change a liquid to a solid, do you add heat or remove heat? You would REMOVE heat! So that would be an EXOTHERMIC reaction.

to change a gas to a liquid, do you add heat or remove heat? You would REMOVE heat! So that would be an EXOTHERMIC reaction.

to change a solid to a liquid, do you add heat or remove heat? You would ADD heat! So that would be an ENDOTHERMIC reaction.

Now go back and look at each reaction and see if you can determine if the reaction is endothermic or exothermic,