Question

The melting of ice is an endothermic change. What best describes the temperature conditions that are likely to make this a spontaneous change?

Answer 1

The melting of ice is an endothermic reaction which means it requires energy or the enthalpy of reaction is positive

For a reaction to be spontaneous the change in free energy should be negative.

ΔG = ΔH - TΔS

Where

ΔG = change in free energy

ΔH = change in enthalpy

ΔS = change in entropy

Now in any case enthalpy will be positive (endothermic)

Here as ice is melting the process if going from less random phase to more random or disorder phase so there is an increase in entropy or ΔS = positive

In order to make ΔG negative, the ΔH < TΔS , this is possible only at higher temperature

Hence, At high temperature the process of melting of ice is spontaneous process.

At low temperature

ΔH > TΔS, and ΔG will become positive making the reverse process (freezing) spontaneous and melting of ice non spontaneous.