What is the mass percent of sodium carbonate, %(m/m) Na2CO3, in a solution prepared by dissolving 4.28 grams of sodium carbonate in 35.11 grams of water.

Question

What is the mass percent of sodium carbonate, %(m/m) Na₂CO₃, in a solution prepared by dissolving 4.28 grams of sodium carbonate in 35.11 grams of water. 

Answer 1

mass % Na₂CO₃ = mass Na₂CO₃ / total mass of sample (x100)

We have the mass of Na₂CO₃, so now we need to find the total mass of the sample.

Total mass = 4.28 g Na₂CO₃ + 35.11 g H₂O = 39.39 g

mass % Na₂CO₃ = 4.28 g / 39.39 g (x100) = 10.9% (m/m)