## 8.49

donnanguyen1d
Posts: 64
Joined: Fri Sep 29, 2017 7:04 am

### 8.49

in chapter 8 problem 49, how did you know the temperature to calculate work was 298K? and why was there a negative sign ?

Kelly Seto 2J
Posts: 30
Joined: Thu Jul 27, 2017 3:00 am

### Re: 8.49

I think if there is no temperature explicitly stated, 298 K is just the standard temperature used in thermodynamics

Alexandria Weinberger
Posts: 51
Joined: Fri Sep 29, 2017 7:03 am

### Re: 8.49

The textbook stated that all temperatures will be assumed to be 298 K unless stated otherwise because that is standard.

Michael Cheng 1C
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Joined: Thu Jul 13, 2017 3:00 am

### Re: 8.49

What is the difference between internal energy and enthalpy?

Brandon Fujii 1K
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Joined: Fri Sep 29, 2017 7:04 am

### Re: 8.49

We use 298K for the standard temperature for thermodynamics because 298K = 25C which is room temperature

Cooper1C
Posts: 50
Joined: Fri Sep 29, 2017 7:07 am

### Re: 8.49

Michael Cheng 1C wrote:What is the difference between internal energy and enthalpy?

H = U + PV. Enthalpy is equal to internal energy plus the product of pressure and volume, so internal energy is included in the enthalpy calculation.

Also, internal energy has to do with the kinetic and potential energies of molecules in a system, while enthalpy relates to the system and its surroundings.

Return to “Reaction Enthalpies (e.g., Using Hess’s Law, Bond Enthalpies, Standard Enthalpies of Formation)”

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