Enthalpy of fusion  [ENDORSED]

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Cristian Carrasco 1F
Posts: 52
Joined: Fri Sep 29, 2017 7:06 am

Enthalpy of fusion

Postby Cristian Carrasco 1F » 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?

Nha Dang 2I
Posts: 53
Joined: Fri Sep 29, 2017 7:07 am

Re: Enthalpy of fusion

Postby Nha Dang 2I » 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.

Erica Nagase 1H
Posts: 30
Joined: Sat Jul 22, 2017 3:00 am

Re: Enthalpy of fusion  [ENDORSED]

Postby Erica Nagase 1H » 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 ()

Liz White 1K
Posts: 35
Joined: Thu Jul 13, 2017 3:00 am

Re: Enthalpy of fusion

Postby Liz White 1K » 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.

Angela 1K
Posts: 80
Joined: Fri Sep 29, 2017 7:05 am

Re: Enthalpy of fusion

Postby Angela 1K » Wed Feb 14, 2018 5:07 pm

We use the equation to find the qice cream because we have to account for the fact that it changes from solid (frozen) to liquid (melted). The accounts for the ice cream changing and then accounts for the phase change, where .

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