heat capacity

[superduper12]

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I understand that for gases at constant P, heat energy goes into PV...thus temperature change not as great as it would have been if volume was held constant

C (at constant pressure) > C (at constant volume)

just a confused about solids and liquids. "the intermolecular forces of a solid or liquid are much stronger than those of a gas. Small changes in the intermolecular distances of noncompressible phases result in large changes in intermolecular potential energy. Intermolecular potential energy does not affect temperature"...from here onwards I don't get it..."and thus heat is absorbed at constant pressure with less change in temperature than when heat is absorbed at constant volume."

correct me if I am wrong. At constant pressure, some of the energy goes into PV and some of it goes into increasing the intermolecular distances, which affects the intermolecular potential energy, but doesn't affect temperature. Since solids have closer intermolecular distances, more energy can go into increasing that distance without changing the temperature. at constant volume, more energy goes into increasing the intermolecular distance and increases the temperature more.

so once again we get C (at constant pressure) > C (at constant volume)...and C for solid > C for liquid....but for water which H bonds
C liquid > C solid

 

[engineeredout]

Ever consider condensing your threads? This is like your tenth one today on gen chem.


When heat is absorbed as constant pressure, some of it goes into PV work, therefore there is less of a temperature change. Because of this, more heat will be required to heat a solid/liquid at constant pressure than constant volume.



Wait, make that 24 on the first page of this subforum alone. Dude chill on the threads. You should be focusing on one thing at a time, not 24.

 

[superduper12]

sorry, will minimize threads.

 

[SKation]

Hello,

Did anybody ever figure out what they were talkin about in the sense of intermolecular forces.

Thanks!

 

[patrickmbyrne]

Ever consider condensing your threads? This is like your tenth one today on gen chem.

When heat is absorbed as constant pressure, some of it goes into PV work, therefore there is less of a temperature change. Because of this, more heat will be required to heat a solid/liquid at constant pressure than constant volume.

THIS
and

The intermolecular forces are going to depend on the phase. Gases have the least intermolecular forces so less energy will be spent overcoming these. Solids have the greatest intermolecular forces so it will take the most energy away from increasing the temperature. Intermolecular force will also be proportional to the density. Temperature is a measure of the average kinetic energy of the system.