# What amount of heat is required to melt #"300 g"# of ice at its freezing point if the enthalpy of fusion is #"6.02 kJ/mol"#?

##### 1 Answer

Sep 27, 2016

For a **phase transition**, we assume a *constant temperature* (and also, pressure). So, the heat flow

#bb(q_P)#

#= bb(mDeltaH)# , if#DeltaH# is in#"J/g"# , or

#= nDeltaH = bb(m/(M_m)DeltaH)# , if#DeltaH# is in#"J/mol"# ,where:

#m# is themassof the ice in#"g"# .#n# is the#bb("mol")# sof the ice.#M_m# is themolar massof the ice in#"g/mol"# .#DeltaH# is theenthalpy of fusion, which is about#"6.02 kJ/mol"# for ice at#0^@ "C"# and#"1 atm"# .

So, simply solve for the heat flow required to melt

#color(blue)(q_P) = (300 cancel"g" xx cancel"1 mol"/(18.015 cancel"g"))("6.02 kJ"/cancel"mol")#

#=# #color(blue)("100. kJ")#