The mass number of sucrose that must be added to 500 g of water is 100.979 grams
To be able to solve this question, we need to use the number of moles concept and mole fraction concept.
<h3>What is the number of moles?</h3>The number of moles is related to the mass of the substance divided by the molar mass of the substance.
From the given parameters;
The number of moles of water = mass/molar mass
- Mass of water = 500 g
- the molar mass of water = 18.02 g/mol
number of moles = 500 g/ 18.02 g/mol
number of moles = 27.75 moles
However,
- the standard vapor pressure of the solvent
= 760 mmHg
- the vapor pressure of the solute = 752 mmHg
Using the mole concept:
By relative lowering of vapor pressure:
The mass of sucrose = number of moles × molar mass
The mass of sucrose = 0.295 moles × 342.3 g/mol
The mass of sucrose = 100.979 grams
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