# Question #0f395

Mar 13, 2014

The density of the mixture is 17.096 g/L

We are given two pieces of information:

• Volume = 3.8L
• Amount of each substance in mol: 0.650 mol Ne, 0.321 mol Kr, and 0.190 mol Xe

Density = $\frac{M a s s}{V o l u m e}$ = $\frac{g}{L}$

Since volume is already in L, we don't need to convert it to other units.

But, we need to find the mass of the mixture in grams, from the amount of each substance in mols.

To do this, we need to know the molar mass (M), of each substance, expressed in g/(mol).

I looked up the Molar Mass of each substance here: http://www.webqc.org/mmcalc.php

• Molar mass of Ne is 20.1797 g/mol
• Molar mass of Kr is 83.7982 g/mol
• Molar mass of Xe is 131.2936 g/mol

Multiplying each of these by the number of mols of the substance gives us the mass in grams.

• Mass of Ne = (0.650 mol * 20.1797 g/mol) = 13.117 g
• Mass of Kr = (0.321 mol * 83.7982 g/mol) = 26.900 g
• Mass of Xe = (0.190 mol * 131.2936 g/mol) = 24.948 g

Total mass in g = 13.117 + 26.900 + 24.948 = 64.965 g

Density = $\frac{M a s s}{V o l u m e}$

Density = $\frac{64.965 g}{3.8 L}$

Density = 17.096 $\frac{g}{L}$