Equation

[Alison Trinh 1E]

What does each variable in this equation represent?

[Jessica Castellanos]

I don't see any equation attached to your post you might want to fix it

[Daniel Yu 1E]

I'm assuming you are talking about the Ideal Gas Law, PV=nRT.
P stands for pressure
V stands for volume
n stands for moles
R is a constant that you use to convert your answer into useful units. Based on your units for your other variables you would have a different R value.
T stands for temperature.

[Nikki Razal 1L]

or you could be talking about the boltzmann formula for entropy , "S=klnW" where, S=entropy, k=1.381*10^-23 j/k (the boltzmann constant), and W is the number of ways that the atoms or molecules in the sample can be arranged with the same total energy

[KDang_1D]

When using the Ideal Gas Law typically, following units are used. However, they may be converted appropriately.
P = atm
V = L
n = moles
R = 0.08206 (Latm)/(molK)
T = K

PV=nRT is also often manipulated to become P=(n/V)RT = CRT, where C = concentration (M=mol/L)