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### Enthalpy of fusion

Posted: Sun Feb 11, 2018 11:45 pm
for problem 2 on the midterm, how would you find the delta H fusion of the ice cream?

### Re: Enthalpy of fusion

Posted: Mon Feb 12, 2018 2:29 am
You set it up as q=mcdeltaT + deltaH(fusion)(1/2m), which becomes deltaH(fusion)=((2)(q-mcdeltaT))/(m). Then you just plug in the numbers and you end up getting 3.7 kJ/g.

### Re: Enthalpy of fusion  [ENDORSED]

Posted: Mon Feb 12, 2018 1:22 pm
The total energy put into the ice cream is equal to the energy needed to raise the temperature from -2.8 to 0degC plus the energy needed to melt it ($q = mc\Delta T + n\Delta Hvap$)

### Re: Enthalpy of fusion

Posted: Tue Feb 13, 2018 5:02 pm
Can someone please explain the answer to this question in more detail? I don't understand why we use q=mcdeltaT + deltaH. Also, I plugged the values into this and got an incorrect answer.

### Re: Enthalpy of fusion

Posted: Wed Feb 14, 2018 5:07 pm
We use the equation $q=mC\Delta T+m\Delta H$ to find the qice cream because we have to account for the fact that it changes from solid (frozen) to liquid (melted). The $mC\Delta T$ accounts for the ice cream changing and then $m\Delta H$ accounts for the phase change, where $\Delta H=\Delta Hfusion$.