1.

R represents the amount of matter, r = 2, r is a constant =? When I was in junior high school, I learned some Olympic mathematics at first, but I forgot what R was called, and some places were also represented by K.

The following t is the absolute temperature, that is, T=300.

From PV=rRT, t becomes 2 times, that is, 2T.

From the internal energy formula E=r*(i/2)*R*T (here, monoatomic molecule i=3), we know that the change of E is r*(3/2)*R*T, that is, the internal energy of 3RT increases.

2.

With the recovery of the initial value, the internal energy of 3RT decreases.

Heat transfer and work:

1.

Due to isobaric expansion, external work w = p * (v2-v1) = p * v.

PV=rRT

So: W= rRT

So: absorbed heat Q= internal energy increment +W=rRT+3RT=4RT.

2.

Considering the constant internal energy in the whole process, the total external work is 4RT.

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It seems that I need to review. I have been talking for a long time.