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Topic: Enthalpy Question help  (Read 577 times)

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Offline exocytosis646

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Enthalpy Question help
« on: January 26, 2019, 02:42:42 PM »
The following would represent enthalpy (a change in potential energy)
    a) When the surrounding air gets colder
    b) When water temperature increases in a calorimeter
    c) When an ice cube melts
    d) When a beaker is heated with a Bunsen burner

This question has been very confusing. I believe the answer may be C since an ice cube melting is a spacial change which may be a change in potential energy. And the others represent temperature changes. But an ice cube melting could also represent a temperature change, so im not sure.

Offline chenbeier

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Re: Enthalpy Question help
« Reply #1 on: January 26, 2019, 02:57:09 PM »
A,B, C and D have temperature changes. Only C has an additional  change. Which one?

Offline exocytosis646

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Re: Enthalpy Question help
« Reply #2 on: January 26, 2019, 03:32:56 PM »
A,B, C and D have temperature changes. Only C has an additional  change. Which one?

A potential energy change. So c is the answer. Thanks

Offline chenbeier

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Re: Enthalpy Question help
« Reply #3 on: January 26, 2019, 04:05:16 PM »
The substance change from solid to liquid.

Offline Borek

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Re: Enthalpy Question help
« Reply #4 on: January 26, 2019, 04:20:12 PM »
But an ice cube melting could also represent a temperature change

Could it? Does the temperature change during the melting? Why is the enthalpy of fusion called a "latent heat"?
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Offline mjc123

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Re: Enthalpy Question help
« Reply #5 on: January 28, 2019, 07:19:01 AM »
I don't get the question. All four involve a change in enthalpy. Have you quoted it correctly? Does it ask which involves a change of enthalpy without a change in temperature?

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