Hydrate Lab Assistance

Data Items

• A: mass of dry crucible and cover
• B: mass of crucible and cover with hydrated crystal
• C: mass of crucible and cover with anhydrous crystal (first heating)
• D: mass of crucible and cover with anhydrous crystal (second heating)
• NOTE: D – C < 0.02 g

Calculations

• E: mass water lost = D – B
• F: mass of anhydrous crystal = D – A
• G: moles water lost = E x (1 mole H2O / 18.02 g H2O)
• H: moles anhydrous crystal = F x (1 mole CuSO4) / 159.61 g CuSO4)
• I: mole ratio = G / H
• J: percent error = [(I – 5)/(5)] x 100%

Possible Factors

• crucible not fully dry before placing hydrate
• some of hydrate jumped out of crucible during heating
• not all water driven off during drying process
• contamination to crucible during process