Melting of Ice in Heat equations

[Grace_Remphrey_2J]

I have a question relating to the following two questions:
4C.11 How much heat is needed to convert 80.0 g of ice at 0.0 8C into liquid water at 20.0 8C (see Tables 4A.2 and 4C.1)?
4C.13 An ice cube of mass 50.0 g at 0.0 8C is added to a glass containing 400.0 g of water at 45.0 8C. What is the final temperature of the system (see Tables 4A.2 and 4C.1)? Assume that no heat is lost to the surroundings.

When working with ice, do we always have to calculate the heat required to melt the ice before we can continue with solving for the heat needed to convert/final temperature? Can I say that any time we are considering phase changes from ice to water we must calculate the heat required to melt the ice first?

Thank you!

[Kimiya Aframian IB]

I have a question relating to the following two questions:
4C.11 How much heat is needed to convert 80.0 g of ice at 0.0 8C into liquid water at 20.0 8C (see Tables 4A.2 and 4C.1)?
4C.13 An ice cube of mass 50.0 g at 0.0 8C is added to a glass containing 400.0 g of water at 45.0 8C. What is the final temperature of the system (see Tables 4A.2 and 4C.1)? Assume that no heat is lost to the surroundings.

When working with ice, do we always have to calculate the heat required to melt the ice before we can continue with solving for the heat needed to convert/final temperature? Can I say that any time we are considering phase changes from ice to water we must calculate the heat required to melt the ice first?

Thank you!

Hi! I think that whenever comparing ice to water, we do need to put them into the same state in our calculations. This would mean that we need to use the enthalpy of melting/fusion to get the solid ice to liquid, and then use q=mct to measure the enthalpy from the increase in temperature of the now-liquid water. Hope this helps!

[Marisa Gaitan 2D]

Hi! Yes, we would need to calculate the enthalpy of fusion first. This value we calculate would then be added to the heat required to raise the temperature to the final desired temperature. And to add on, remember this goes for phase changes from liquid to gas as well. Hope this helps!