Answers:
a. 1.28 mol/L; b. 17.0 %; c. 0.0227; d. 1.29 mol/kg
Explanation:
a. <em>Molar concentration
</em>
<em>c</em> = moles/litres
Moles = 167 × 1/159.61 Do the calculation
Moles = 1.046 mol
Litres = 820 × 1/1000 Do the calculation
Litres = 0.8200 L Calculate the molar concentration
<em>c</em> = 1.046/0.8200 Do the division
<em>c</em> = 1.28 mol·L⁻¹
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b. <em>Percent by mass
</em>
Mass % = mass of solute /mass of solution × 100 %
Mass of solution = volume × density Insert the values
Mass of solution = 820 × 1.195 Do the multiplication
Mass of solution = 979.9 g Calculate the mass %
Mass % = 167/979.9 × 100 Do the operations
Mass % = <em>17.0 %</em>
===============
c. <em>Mole fraction</em>
χ = moles of solute/(moles of solvent + moles of solute)
Mass of solvent = mass of solution – mass of solute
Mass of solvent = 979.9 – 167 Do the subtraction
Mass of solvent = 812.9 g Convert to moles
Moles of water = 812.9 × 1/18.02 Do the calculation
Moles of water = 45.11 mol Calculate the total moles
Total moles = 1.046 + 45.11 Do the addition
Total moles = 46.16 mol Calculate the mole fraction
χ = 1.046/46.16 Do the division
χ = 0.0227
===============
d. <em>Molal concentration
</em>
<em>b</em> = moles of solute/kilograms of solvent
Mass of solvent = 812.9 g = 0.8129 kg Calculate the molal concentration
<em>b</em> = 1.046/0.8129 Do the division
<em>b</em> = 1.29 mol/kg
