## change in internal energy

Stephanie tran 1J
Posts: 50
Joined: Fri Sep 29, 2017 7:04 am

### change in internal energy

for examples involving calculating energy changes when heating an ideal gas, why do you have to separate the problem into two steps, step 1 being heating at constant volume to the final temperature, and step 2 being allowing the gas to expand isothermally?

Emilie Hoffman 1E
Posts: 55
Joined: Fri Sep 29, 2017 7:04 am

### Re: change in internal energy

Because we don't have a way of calculating that kind of energy change at the same time because both of our equations deal with either a change in one or another.

Rishi Khettry 1L
Posts: 29
Joined: Fri Sep 29, 2017 7:05 am

### Re: change in internal energy

Separating the steps allows us to perform two different calculations which would give us the final correct answer. It is impossible to calculate them simultaneously as there is not an equation we have learned to allow us to deal with both forms of energy change at the same time.

gwynlu1L
Posts: 62
Joined: Fri Sep 28, 2018 12:19 am

### Re: change in internal energy

I think it's better to think of these questions as 2 separate questions, not just 1 question. Reversible and irreversible reactions are not same, so their methods of solving are different. solving that kind of question is knowing that 2 separate experiments would be taking place.

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