How Do You Calculate Temperature and Energy Changes in Mixed Ideal Gases?

[claudiadeluca]

I tried but I cannot do it. Please help.

Two rigid adiabatic containers have inside the same ideal gas, respectively N1=3mol at a temperature T1=340K and N2=2mol at a temperature T2=280K. The two containers come into contact by opening a faucet, and the gas mixes, getting to a temperature T3.

Calculate:

1) the variation of the total internal energy of the gas.
2) the value of the final temperature T3.

I really need a hand, if you don't want to solve it please tell me how to do it. Any help is truly appreciated. Pardon the probably incorrect use of words, I'm not english.

 

[chaoseverlasting]

Here, I think the total internal energy will remain constant. Since U=nf RT/2, you can use that to find the internal energy of the gas in both the parts and add it up to find the final internal energy which will have n1+n2 moles of the gas.