Given An aqueous solution contains 5.8% KBr by mass.
That means 5.8 g of KBr present in 100 mL(=0.1 L) of the
solution
Molar mass of KBr = At.mass of K + At.mass of Br
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= 39 + 80
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= 119 g/mol
So number of moles of KBr , n = mass/molar mass
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= 5.8 g / 119 (g/mol)
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= 0.0487 mol
(a) Molarity , M = number of moles / Volume in L
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= 0.0487 mol / 0.1 L
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= 0.487 M
We cannot calculate the mole fraction of solution we
calculate only the mole fraction of either solute or solvent