The ideal gas law is sometimes written in terms of R, the ideal gas constant, instead of k, Boltzmann’s constant.
where n is the number of moles of the gas, and R = 8.31
J/mol
Because the two gas laws are the same, N k = n R. But N is the number of molecules, which is nNA, the number of moles times Avogadro's number. This yields the relation between k and R:
When we study kinetic theory, we will find out what R (or k) really is.
Question:
A sample of CO2 occupies 2.1 liters at 47° C and 3.1 Atm. How many moles and molecules are there in the sample?
Answer:
Number of moles =>
\[ \rm \mathbf{ n = \frac{pV}{RT}} \] T must be in Kelvin! T = (47 + 273) K = 320 K.
= 0.248 molesNumber of molecules = N = nNA = 0.248
$\cdot$ 6.023$\cdot$ 1023 = 1.5$\cdot$ 1023