4C.13 phase change

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4C.13 phase change

Postby rachelle1K » Fri Feb 07, 2020 11:40 pm

4C.13 says, "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?"

I was wondering why, when calculating the heat absorbed, do we add (50g)(4.184J.°C-1.g-1)(Tfinal) to (n)(deltaH) ? I was solving the problem solely using the heat absorbed as n x deltaH. Any help would be appreciated, thanks!

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Re: 4C.13 phase change

Postby KnarGeghamyan1B » Sat Feb 08, 2020 1:29 am

The n delta h represents the Heat of fusion of the ice cube as it melts to a liquid and the mCdeltaT is the heat needed to go from 0 degree liquid to the final temperature. Think of it as the graph we went over in class with the steps of alternating horizontal and diagonal lines.

Sartaj Bal 1J
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Re: 4C.13 phase change

Postby Sartaj Bal 1J » Sat Feb 08, 2020 6:47 pm

For phase change problems, I would suggest taking everything into account one step at a time. In this case, the ice first has to melt (1) and then go to the final temperature (2). So there would be two components. The water in the glass just has to go to the final temperature (1). Hope this helps!

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