Each of the following hydrate samples has a mass of 15.0 g
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Each of the following hydrate samples has a mass of 15.0 g. All samples are pure.
• Copper(II) sulfate pentahydrate, CuSO₄·5H₂O
• Barium chloride dihydrate, BaCl₂·2H₂O
• Sodium carbonate decahydrate, Na₂CO₃·10H₂O
• Calcium sulfate hemihydrate, CaSO₄·½H₂O (molar ratio 0.5 mol H₂O per mol CaSO₄)
(a) Determine the molar mass of each hydrate sample listed.
(b) Calculate the number of moles of formula units present in each 15.0 g sample.
(c) Rank the four samples from the greatest to the fewest number of formula units present. Show relevant reasoning.
(d) If all waters of hydration were released upon heating, rank the samples from the greatest to the fewest number of water molecules that would be produced. Include supporting calculations or logic.