## Change in Entropy [ENDORSED]

Niveda_Tennety_1H
Posts: 21
Joined: Wed Sep 21, 2016 2:59 pm

### Change in Entropy

For calculations involving (Delta S) = nRln(V2/V1), when can you assume that there is only 1 mol of the substance?

Chem_Mod
Posts: 17487
Joined: Thu Aug 04, 2011 1:53 pm
Has upvoted: 393 times

### Re: Change in Entropy  [ENDORSED]

If a molar quantity is not given, you can assume it's one mol. However, if you are given a particular volume at STP, then you should know that 1 mol of ideal gas is 22.4L at STP, so you can also calculate from there. However, you should always double check through the wording of the problem to make sure the information is not in there already. For example, if you are given a chemical reaction and told that you have a given amount of starting material, then you could use molar ratios to determine amount of product.