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September 23, 2014

September 23, 2014

Posted by **anonymous** on Sunday, January 28, 2007 at 4:45pm.

1. Why does vapor pressure change with temperature?

2. The assumption was made that the vapor pressure of water is negligible at a temperature close to zero. Find the actual vapor pressure of water at you low temperature and comment on the validity of the assumption.

(what equations/calculations do I use?)

3. The assumption was also made that the slight changes in "h", the depth under the surface of the water, will not significantly change the total pressure in the graduation cylinder. Comment on the validity of this assumption.

4. Write out the long "two-point" form of the Clausius-Clapeyron equation. Why does the graphical of analysis give a better value for the enthalpy of vaportization than does the form of the Clausius-Clapeyron equation using two temperature-vapor pressure values?

Please help! Thanks !!

1. Why does vapor pressure change with temperature?

2. The assumption was made that the vapor pressure of water is negligible at a temperature close to zero. Find the actual vapor pressure of water at you low temperature and comment on the validity of the assumption.

(what equations/calculations do I use?)

3. The assumption was also made that the slight changes in "h", the depth under the surface of the water, will not significantly change the total pressure in the graduation cylinder. Comment on the validity of this assumption.

4. Write out the long "two-point" form of the Clausius-Clapeyron equation. Why does the graphical of analysis give a better value for the enthalpy of vaportization than does the form of the Clausius-Clapeyron equation using two temperature-vapor pressure values?

thankyou !!

hey--we just did this lab! and ahhh! i'm still clueless about the two point clausius-clapeyron eq. anyone have any more help?

We just did this same lab also and it was so confusing, but you helped just a little bit hee hee internet is great!!! :)

- chemistry -
**marj**, Thursday, November 22, 2007 at 6:18amcan you answer this??

what are the 2 assumptions of KMT that maybe considered vaque

- AP Chemistry -
**Anonymous**, Tuesday, February 12, 2008 at 7:40pmTwo- point equation:

ln (P1/P-2) = - (ÄHvap/R)(1/T2-1/T1)

The graphical analysis gives a more exact value because it takes into account possibly erroneous data points, making an “average”, “trend” or “best fit” line that is as close as possible to all data points. The equation method only utilizes two of the data points, which may or may not be representative of the rest of the data, and which may or may not be skewed.

- AP Chemistry -
**Hello**, Monday, January 5, 2009 at 6:34pmthank you!! i was stuck on the last question but this helped :))

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