In chemistry, n molecules of an ideal gas have pressure (P), volume (V), and temperature (T) that stand in the following relation, where R is a constant.

PV = nRT

If you solve for n what would be a good equation?
I came up with n=PV/RT

Some other choices are
n= PV - RT
n= PVRT

"I came up with n=PV/RT"

is correct.

The equation n = PV/RT is the correct equation when solving for the number of moles (n) of an ideal gas. This equation is derived from the ideal gas law, PV = nRT, by rearranging the terms to solve for n. So, n = PV/RT is the correct equation to use. The other choices you mentioned, n = PV - RT and n = PVRT, are not correct and do not represent the relationship between the variables in the ideal gas law.

To solve for the number of molecules (n) in the ideal gas equation PV = nRT, you need to isolate n on one side of the equation. Here's how you can do it:

1. Start with the equation: PV = nRT
2. Divide both sides of the equation by RT to get n alone:
PV / (RT) = n

So, the correct equation to solve for n is indeed:
n = PV / (RT)

Your solution of n = PV/RT is absolutely correct. This equation allows you to calculate the number of molecules in an ideal gas given its pressure (P), volume (V), temperature (T), and the gas constant (R).