Answer:
[KOH] = 1.47 M
[KOH] = 1.22 m
KOH = 6.86 % m/m
Explanation:
Let's analyse the data
1.87 L is the volume of solution
Density is 1.29 g/mL → Solution density
155 g of KOH → Mass of solute
Moles of solute is (mass / molar mass) = 2.76 moles.
Molarity is mol/L → 2.76 mol / 1.87 L = 1.47 M
Let's determine, the mass of solvent.
Molality is mol of solute / 1kg of solvent
We can use density to find out the mass of solution
Mass of solution - Mass of solute = Mass of solvent
Density = Mass / volume
1.29 g/mL = Mass / 1870 mL
Notice, we had to convert L to mL, cause the units of density.
1.29 g/mL . 1870 mL = Mass → 2412.3 g
2412.3 g - 155 g = 2257.3 g of solvent
Let's convert the mass of solvent to kg
2257.3 g / 1000 = 2.25kg
2.76 mol / 2.25kg = 1.22 m (molality)
% percent by mass = mass of solute in 100g of solution.
(155 g / 2257.3 g) . 100g = 6.86 % m/m
