Everly asked in Science & MathematicsChemistry · 1 year ago

# 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?

Update:

(AT STP)

### 2 Answers

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• 1 year ago
Favorite Answer

Gas solution....

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

Volume=

(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 W
Lv 7
1 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.

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