Calculate the weight of 0.1 mole of sodium carbonate

The measured density at NTP of He is 0.1784 g L^(-1) . Calculate the weight of 1 "mole" of He .

Calculate the mass of 0.1 mole of KNO_(3) .

Calculate the number of atoms in 0.2 mole of sodium (Na).

(a) Define molarity. (b) Calculate the molarity of sodium carbonate solution, containing 0.53 g of sodium carbonate dissolved in 200 mL of the solution.

Calculate the number of moles of sodium (Na) atoms present in 11.5 g of sodium.

In a sample of sodium carbonate some sodium sulphate is also mixed. 1.25 g of this sample is dissolved and the volume made up to 250 mL. 25 mL of this solution neutralises 20 mL of (N)/(10) sulphuric acid. Calculate the percentage of sodium carbonate in the sample.