Latent Heat of Vaporisation

Hey.

So I have a question that required me to calculate the energy to make a cup of coffee from ice initially at -40 degrees. So I calculated the Energy to raise the ice to water at 100 degrees (Including the heat of fusion to melt the ice) but I have an issue.

Do I need to include the energy required to boil the water, i.e The Latent Heat of Vaporisation? The questions asks for the energy required to make the coffee and as you obviously dont want to evaporate the water then surely you dont need to include this energy?

I just ask as the question gives the required information to calculate this but I dont think its needed, probably just there to throw me off.

Thanks

Reply 1

alow

19

Original post by Eremor

Hey.

So I have a question that required me to calculate the energy to make a cup of coffee from ice initially at -40 degrees. So I calculated the Energy to raise the ice to water at 100 degrees (Including the heat of fusion to melt the ice) but I have an issue.

Do I need to include the energy required to boil the water, i.e The Latent Heat of Vaporisation? The questions asks for the energy required to make the coffee and as you obviously dont want to evaporate the water then surely you dont need to include this energy?

I just ask as the question gives the required information to calculate this but I dont think its needed, probably just there to throw me off.

Thanks

Nah, you don't.

What temperature should coffee even be? It definitely shouldn't boil off though.