4/27/17 Lecture notes (8) Ch 23 Chemical
Thursday, April 27, 20179:33 AM
The standard state of a property X desginated by X knot is defined as such:
Substances and elements : most stable form of that material at the T of interest and 1 bar of pressure
Solutions : 1 M concentration
Allows the tabulation and reporting of data from various sources to be accomplished.
This is a state function because it does not depend on the path.
Which of the following will have a greater entropy?
a) 75 J reversible heat at room temperature
b) Add 75 J reversible heat at 150 degrees Celsius
c) Add 75 J reversible heat at 10 degrees Celsius
Answer: C: there is a bigger difference when you start at a colder temperature.
Entropy at constant temperature
week 4 ch 22 23 Page 1 1) At the transition temp, the temp of the substance remains constant as heat is supplied
2) At the temperature of a phase transition the transfer of heat is reversible
3) If the transition takes place at constant pressure
Calculate the standard enthalpy of vaporization of benzene at its normal boi