How do you know if a reaction is exothermic?

Question

i know it gives off energy but

Which of the following are exothermic?

melting chocolate

burning gasoline

freezing ice cream

condensing water vapor

cooling hot water

burning a match

Answer 1

If energy (heat) have to be added to make the rx occur it is ENDOthermic.  Ex. melting chocolate

If energy (heat) is released during the rx it is EXOthermic.  Ex. cooling of hot water

Answer 2

burning gas

freezing ice cream

condensing water vapor

cooling hot water, and

burning a match are exothermic

- exothermic things give off energy and endothermic things gain heat

Answer 3

burning gasoline

condensing water vapor

cooling hot water

burning a match

All exothermic

Theoretically, try these in vessel. The vessel would be hot.