P/T = constant

PV/T = constant

## PV = nRT

Where they realized that this depends on the number of molecules in the gas.

n = number of moles of gas

R=8.31 J/K/mol

The above equation is what often appears in chemistry books.

In a physics book you will often see this equation expressed as

PV = NkT

Boltmann k = R/ NA = 1.38 x 10 –23 J/K

NA = 6.022 x 10 -23 per  (g mol)

N = number of molecules or particles

What is important to note here is what we actually mean by temperature, heat, and internal energy, all concepts we will explore in the coming week.

We can think of temperature as proportional to the average kinetic energy per molecule. T = avg KE * 2/(3k)

Heat is actually the flow of energy from one object to another (either by conduction, convection, or radiation).

The internal energy is the sum of the molecular energies of a substance (due to both the kinetic energies and the electrostatic potential interaction energies).

The internal energy is usually expressed as 3/2 NkT