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Enthalpy of fusion

Posted: Sun Feb 11, 2018 11:45 pm
by Cristian Carrasco 1F
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
by Nha Dang 2I
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
by Erica Nagase 1H
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 ()

Re: Enthalpy of fusion

Posted: Tue Feb 13, 2018 5:02 pm
by Liz White 1K
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
by Angela 1K
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 .