5.5 Molar Volume Molar Mass and Density lesson

Question 1

What is molar volume, what conditions do we often use to specify it, define this conditions?

Answer 1

The volume occupied by one mole of a substance, and we often specify the molar volume under conditions known as standard temperature (T = 0`C or 273 K) and pressure (P = 1.00 atm), abbreviated as “STP”.

Question 2

What is molar mass?

Answer 2

Molar mass (M) is mass (g)/moles (n).

Question 3

What is molar density, and to what is the density of a gas directly proportional?

Answer 3

Molar density is moles (n)/volume (L). Density is molar mass (g/n)/molar volume (n/L), and the density of a gas is directly proportional to its molar mass.

Question 4

What can we determine about any ideal gas in moles at STP; what is the approximate value at 1 mol?

Answer 4

We can determine the molar volume of any ideal gas, and the approximate molar volume of 1 mol of an ideal gas at STP is 22.4 L.

Question 5

What can be found using the ideal gas law and molar density together?

Answer 5

The ideal gas law, PV = nRT, can be represented as (molar density) n/V = P/RT. By multiplying the molar density (n/V) and the molar mass (M) we can obtain the density, d = mass (g)/ volume (L).
(n/V)M = PM/RT becomes d = PM/RT