Draw the structural formula for a hydrogen molecule an oxygen molecule. Remember that each line represents an electron pair bein
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Answer:
Explanation:
The <em>vapor pressure lowering</em> is a colligative property and it follows Raoult's law.
The <em>vapor pressure lowering</em> of a solvent in a solution, ΔP, is equal to the mole fraction of the solute, Xsolute, multiplied by the vapor pressure of the pure solvent, P°.
ΔP and P⁰ are given:
- ΔP = 1.39mmHg
- P⁰ = 55.32mmHg
<u>1. Mole fraction of solute</u>
Thus, you can calculate Xsolute:
<u>2. Moles of solute</u>
Now you can calculate the number of moles of water and the number of moles of solute.
- Number of moles of water = mass in grams / molar mass
- Number of moles of water = 1,250g/18.015 (g/mol) = 69.3866mol
- Xsolvent = 1 - Xsolute = 1 - 0.02513 = 0.97487
- Xsolvent = moles of solvent / moles of solution
- 0.97487 = 69.3866mol / moles of solution
- moles of solution = 71.1752mol
- moles of solute = moles of solution - moles of solvent = 71.1752mol - 69.3866mol = 1.7886mol
<u>3. Mass of urea</u>
Formula:
- Mass = number of moles × molar mass
- Mass = 1.7886 mol × 60.06 g/mol = 107.42 g
You must round to 3 significant figures: 107 g