## PV=nRT

$\Delta U=q+w$

305113590
Posts: 66
Joined: Fri Sep 28, 2018 12:28 am

### PV=nRT

When can we use PV=nRT and in what conditions? And what is the difference between PV=nRT and P∆V=∆nRT?

Jonathan Zhao 4H
Posts: 57
Joined: Fri Sep 28, 2018 12:26 am

### Re: PV=nRT

This equation describes an ideal gas, which is essentially a simplified model of real gases to help us in calculations. Since there are 4 unknown's in this equation, we can use this equation when we have three givens, which then can be used to calculate the final unknown.

Diviya Khullar 1G
Posts: 59
Joined: Fri Sep 28, 2018 12:19 am

### Re: PV=nRT

P$\Delta$V=$\Delta$nRT is used when you are dealing with equations where the volume and the number of moles is changing.

chris_tsai_4H
Posts: 52
Joined: Fri Sep 28, 2018 12:26 am

### Re: PV=nRT

This equation is given for the ideal gas law so you'd only us it when you have a problem where the volume and moles of a gas are changing.

Angel Chen 2k
Posts: 59
Joined: Fri Sep 28, 2018 12:20 am

### Re: PV=nRT

First of all, this equation can only be used on ideal gas. 1) The volume of gas particles are really small, which can be neglected 2) Gas particles are always moving around randomly in the system 3) There are no interactions between the particles 4) The collisions between gas particles and the wall of the system are elastic that does not cost any energy. We can use this equation to calculate any one variable in it if we know the others. Also, we can use this equation to learn the relationships among temperature, pressure, and amount of substance. The difference between these two equations is that the second one is normally used under the situation that gas does work on the environment. The reason is, only if the gas does work, the volume can change, which causes the change of temperature in turn. Hope this helps!

Elizabeth Kim 4E
Posts: 60
Joined: Fri Sep 28, 2018 12:29 am

### Re: PV=nRT

It can only be used on idea gases