Chemistry Grades and Chemistry Help

I have made some chemistry help videos which explain properties of gases, including pressure and temperature. These videos are currently free but will soon become part of the protected content of this membership site.

The first 3 videos are on the properties of gases, the 4th describes the 6 typical versions of ideal gas law problems you will see on a test or homework.  Then the 6 homework videos go through each type of problem in careful detail, with an added bonus.  I tried to point out common mistakes you will make when you work these problems.  If you are prepared for these mistakes then your grades should improve.

Please respond to this post on these videos, are they useful, are there any mistakes, what is missing, what other topics should I cover for ideal gases? Are there any web problems (bad URL, no file, 404 code) ?

http://media.chemistrygrades.com/IdealGas_Intro.swf
http://media.chemistrygrades.com/IdealGas_Intro2.swf
http://media.chemistrygrades.com/IdealGas_Intro3.swf
http://media.chemistrygrades.com/IdealGas_questions.swf
http://media.chemistrygrades.com/IdealGas_homework1.swf
http://media.chemistrygrades.com/IdealGas_homework2.swf
http://media.chemistrygrades.com/IdealGas_homework3.swf
http://media.chemistrygrades.com/IdealGas_homework4.swf
http://media.chemistrygrades.com/IdealGas_homework5.swf
http://media.chemistrygrades.com/IdealGas_homework6.swf