Question on gases physics/chemistry

[GreenPrint]

When I took AP Physics we did similar problems... almost identical lol

Homework Statement

http://img252.imageshack.us/img252/6931/chemistry.jpg

Uploaded with ImageShack.us

Homework Equations

SEE BELOW

The Attempt at a Solution

http://img100.imageshack.us/img100/7521/chemistryscoringguideli.jpg

Uploaded with ImageShack.us

http://img440.imageshack.us/img440/7434/chemistryanswer.jpg

Uploaded with ImageShack.us

 

[GreenPrint]

please anybody?

 

[GreenPrint]

? ANyone know?

 

[GreenPrint]

mathematically I don't see how i am wrong

 

[willem2]

You have K = 3nRT. There's no mass in this equation. K does not depend on mass.

 

[GreenPrint]

yes but moles is directly proportional to mass so decreasing mass will decrease mass which will decrease kinetic energy right?