Molarity and Molality. Chemistry.?
If you add 450 moles of Hydrogen to 6,800 moles of Nitrogen gas, what would be the Molarity and Molality of the gas solution? What is the formula you used?
- pisgahchemistLv 71 year agoFavorite Answer
H2 and N2 don't react at STP, so all you have is a mixture. The substance in greater amount is the "solvent", in this case the nitrogen, and H2 will be the "solute."
At STP, 1 mol of any gas occupies a volume of 22.414L
(450 mol + 6800 mol) x (22.414 L / 1 mol) = 1.625x10^5 L
Molarity of H2 = 450 mol / 1.625x10^-5L = 2.77x10^-3 mol/L = 2.77x10^-3M H2
Molality = moles solute / kg of solvent
6800 mol N2 x (28.0g N2 / 1 mol N2) x (1kg / 1000g) = 190 kg N2
Molality = 450 mol / 190 kg = 2.36 m H2
- Dr WLv 71 year ago
Although I agree with pisgahchemists math, I can't say it's very common to refer to the concentration of gas phase mixtures in terms of M and m. Usually, we use mole fraction.. or ocassionally mass fraction.