Question

LAB RESULTS

mass of empty beaker	85.000 g
mass of beaker and copper (II) sulfate pentahydrate	90.000 g
mass of empty test tube	27.400 g
mass of test tube after heating and cooling	28.993 g

Question

1. How many moles of copper were in the copper oxide formed? The molar mass of copper (II) sulfate pentahydrate is 249.68 g/mol. For best accuracy, use the mass measurements read using the balance.2. Calculate the mass of oxygen in the copper oxide. The molar mass of copper is 63.55 g/mol and the molar mass of oxygen is 16.00 g/mol.

2. Calculate the mass of oxygen in the copper oxide. The molar mass of copper is 63.55 g/mol and the molar mass of oxygen is 16.00 g/mol

Answer 1

Mass of Copper (II) sulphate pentahydrate = 90.000 - 85.000 g = 5 g

Molar mass of Copper (II) sulphate pentahydrate = 249.68 g/mol

Moles of Copper (II) sulphate pentahydrate = 5 / 249.68 = 0.02002 moles.

Mass of Copper (II) sulphate = 249.68 - 90 = 159.68 g

Mass of Copper = 63.55 g

Molar Mass of Copper Oxide = 63.55 + 16 = 79.55 g

Mass of Copper Oxide = 28.993 - 27.400 = 1.593 g

Moles of copper oxide formed = 1.593 / 79.55 = 0.02002

Mass of Copper in the Copper Oxide = (63.55/79.55)*1.593 = 1.276 g

Mass of Oxygen in the Copper Oxide = 1.593-1.276 = 0.317 g