## Question from test 1

$\Delta U=q+w$

Mike Matthews 1D
Posts: 59
Joined: Fri Sep 29, 2017 7:04 am

### Question from test 1

Hi, I still do not understand the following question from test 1: "Answer yes or no if heat is being transferred in the following processes, and justify your reasoning.
a. A tank of liquefied propane is punctured, emitting gaseous propane vapors.
b. A balloon filled with gas is expanded to a larger volume and lower pressure while maintaining the same temperature."
If someone could please explain in detail the answer to this question that would be awesome.

Cristina Sarmiento 1E
Posts: 52
Joined: Wed Nov 16, 2016 3:02 am

### Re: Question from test 1

a. Yes, there is a phase change occurring because liquefied propane was released as gaseous propane vapors.
b. Yes, the temperature remained constant, meaning the surroundings had to supplement heat to keep the temperature from changing.