7th edition 4C.3

Moderators: Chem_Mod, Chem_Admin

Daisylookinland
Posts: 46
Joined: Fri Sep 28, 2018 12:28 am

7th edition 4C.3

Postby Daisylookinland » Wed Jan 30, 2019 8:29 pm

This question, you have to use the formulas: qp=nCpDeltaT and qv=nCvDeltaT, but in the solution book they substitute Cp for (5/2R) and Cv for (3/2R). Can someone explain these substitutions?

Venya Vaddi 1L
Posts: 96
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 2 times

Re: 7th edition 4C.3

Postby Venya Vaddi 1L » Thu Jan 31, 2019 4:54 pm

The textbook shows the derivation of Cp,m=Cv,m+R.

For a monatomic gas, Cv,m=delta U/delta T, which gives 3/2*R. (this derivation is also shown in the book on page 265 of the seventh edition in detail).

Using this result for Cv,m and the above formula, Cp,m is 5/2*R.


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

Who is online

Users browsing this forum: No registered users and 1 guest