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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
Question 2
The sodium sulfate solution was made by dissolving 28.4 g of sodium sulfate in water to make 250 cm³. Calculate the concentration of this solution in g dm⁻³. Give ... show full transcript
Worked Solution & Example Answer: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
Step 1
Calculate the concentration of this solution in g dm⁻³
Answer
To calculate the concentration in grams per cubic decimeter (g dm⁻³), we need to convert the volume from cm³ to dm³.
1 dm³ = 1000 cm³
Thus, 250 cm³ = 0.250 dm³.
Using the formula for concentration:
ext{Concentration (g dm}^{-3}) = rac{ ext{mass (g)}}{ ext{volume (dm}^{3})}
Substituting the values:
ext{Concentration} = rac{28.4 ext{ g}}{0.250 ext{ dm}^{3}} = 113.6 ext{ g dm}^{-3}
Rounding to three significant figures, the concentration is 114 g dm⁻³.
Step 2
Write the formula of sodium sulfate using this information
Answer
The formula for sodium sulfate can be derived from its ions. Sodium sulfate is composed of sodium ions (Na⁺) and sulfate ions (SO₄²⁻).
To balance the charges, we require two sodium ions for every sulfate ion:
Thus, the formula for sodium sulfate is Na₂SO₄.