Measuring solubility [chemistry only]
2 marks · EasyA student found that 25.8 g of sodium chloride was obtained after evaporating all the water from a saturated solution made with 75 g of water at a certain temperature.
Calculate the solubility of sodium chloride in g per 100 g water at that temperature. Show your working.
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
34.4 g/100g water (±0.1)
Also accept: 34.5
Common mistakes: Forgetting to scale to 100g water (leaving answer as 25.8g per 75g water).
Show mark scheme and worked solution
Marking points
M1 · 1 mark · Correctly uses the formula to scale up to 100 g water: or equivalent.
A1 · 1 mark · Correct answer of 34.4 (accept 34.4–34.5) g per 100 g water. (follow-through)
Worked solution
Solubility (g/100g water) = (mass of solute / mass of water) 100
So, the solubility of sodium chloride is 34.4 g per 100 g water at that temperature.