Question

Which of the following are exothermic processes?
1. boiling water
2. freezing water
3.condensation of steam
4. melting ice

My guess is 1. & 4. is that correct

Answer 1

nope, the processes you chose are actually endothermic, boiling water takes energy/heat. you're looking for a process in which the substance decreases in enthalpy (in other words, energy was given to the surroundings).

Answer 2

Exothermic refers to a transformation in which a system releases energy (heat) to the surroundings:
Q < 0
When the transformation occurs at constant pressure:
∆H < 0
and constant volume:
∆U < 0
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Answers: 2. freezing water 3.condensation of steam
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freezing water, means the system loses heat to the surroundings ( heat leaves the water to make it freeze)

condensation of steam, means when the steam condenses the heat of condensation is given off and releases heat to outside the system