redict whether the changes in enthalpy, entropy, and free energy will be positive or negative for the melting of ice, and explain your predictions. How does temperature affect the spontaneity of this process?

Question

tywower · Answer

@aaronq

empty · Answer

Well intuitively what do you expect out of this? When melting will the ice gain or lose heat? When a solid turns to liquid does the disorder increase or decrease?

tywower · Answer

I don't know but the enthalpy is positive entropy is decreasing and free energy is negative that's what I can see but the don't know the other part

empty · Answer

Are you familiar with exothermic and endothermic? These are enthalpy changes, it's really just a bunch of fancy words.

Enthalpy is the amount of heat inside of something. So if something loses heat, the heat has to go somewhere, and that heat will rise the temperature, making it warmer, that's what exothermic is. Endothermic is the other way around.

In symbols:
$\Delta H < 0$ Exothermic
$\Delta H > 0$ Endothermic

So when you melt ice, you're turning something that's cold into something warm and putting energy into it, so the ice has to absorb heat to melt. This means that the internal energy is going up! This means $\Delta H>0$ which is endothermic!

Now you can literally use this formula to see the relationship between free energy, enthalpy, temperature, and entropy:

$$\Delta G = \Delta H - T \Delta S$$