Solubility curves
4 marks · NormalThe following masses were recorded during a solubility experiment:
| Measurement | Mass (g) |
|---|---|
| Mass of evaporating dish | 18.50 |
| Mass of dish + solution | 53.40 |
| Mass of dish + dry solid after evaporation | 29.10 |
Calculate the mass of solid obtained from the solution.
Calculate the mass of water that was present in the solution.
Calculate the solubility of the solid (in g per 100 g water) using your results.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) 10.60 g · must show 29.10 - 18.50 = 10.60
(b) 24.30 g · must show 53.40 - 29.10 = 24.30
(c) 43.6 g per 100 g water g/100g water · must show (10.60 / 24.30) × 100 = 43.6
Show mark scheme and worked solution
Marking points
A1 (a) · 1 mark · Correct subtraction for mass of dry solid: (29.10 - 18.50) = 10.60 g.
A2 (b) · 1 mark · Correct subtraction for mass of water: (53.40 - 29.10) = 24.30 g.
M1 (c) · 1 mark · Substitutes values into solubility equation: (mass of solute / mass of solvent) × 100. (follow-through)
A3 (c) · 1 mark · Calculates correct answer: (10.60/24.30) × 100 = 43.6 (with or without units). (follow-through)
Worked solution
a) Mass of dry solid = 29.10 g - 18.50 g = 10.60 g
b) Mass of water = 53.40 g - 29.10 g = 24.30 g
c) Solubility (g/100g) = (10.60 / 24.30) × 100 = 43.6 g per 100 g water