10.2. Mass, Volume, and the Mole http://www.ck12.org
FIGURE 10.10
Balloons filled with helium gas float in air
because the density of helium is less than
the density of air.What is the density of nitrogen gas at STP?
Step 1: List the known quantities and plan the problem.
Known
- molar mass of N 2 = 28.02 g/mol
- 1 mol = 22.4 L
Unknown
- density of N 2 =? g/L
Molar mass divided by molar volume yields the gas density at STP.
Step 2: Calculate.
28. 02 g
1 mol×1 mol
22. 4 L=^1 .25 g/L