The sodium sulfate solution was made by dissolving 28.4 g of sodium sulfate in water to make 250 cm³ - Edexcel - GCSE Chemistry Combined Science - Question 2 - 2020 - Paper 1

To find the concentration of sodium sulfate in grams per cubic decimeter (g dm⁻³), we use the formula:

1. Convert the volume from cm³ to dm³:

   • Since 1 dm³ = 1000 cm³, 250 cm³ = 0.250 dm³.

2. Substitute the values into the formula:

   • Mass of sodium sulfate = 28.4 g
   • Volume = 0.250 dm³
   ext{Concentration} = rac{28.4 ext{ g}}{0.250 ext{ dm}³} = 113.6 ext{ g dm}^{-3}

3. Round the answer to three significant figures:

   • The final concentration of the solution is 114 g dm⁻³.