Answer:
CaSO4•3H2O.
Step-by-step explanation:
Let the compound be CaSO4.xH2O.
The following data were obtained from the question:
Mass of hydrated compound (CaSO4.xH2O) = 0.4813g
Mass of anhydrous compound (CaSO4) = 0.3750g
Next we shall determine the mass of the water is the hydrated compound.
This is illustrated below:
Mass of water = mass of hydrated – mass of anhydrous.
Mass of water = 0.4813 – 0.3750
Mass of water = 0.1063g
Next, we shall determine the number of mole of the anhydrous compound and the number of mole of the water present in the compound. This is illustrated below:
Molar mass of anhydrous CaSO4 = 63.5 + 32 + (16x4) = 159.5g/mol
Mass of anhydrous CaSO4 = 0.3750g
Mole of anhydrous CaSO4 =...?
Mole = mass /Molar mass
Mole of anhydrous CaSO4 = 0.3750/159.5 = 2.35×10¯³ mole
Molar mass of H2O = (2x1) + 16 = 18g/mol
Mass of H2O = 0.1063g
Number of mole of H2O =.?
Mole = mass /Molar mass
Mole of H2O = 0.1063/18 = 5.91×10¯³ mole
Next we shall determine the ratio of number of mole of anhydrous CaSO4 to that of H2O. This is illustrated below:
Mole of anhydrous CaSO4 = 2.35×10¯³ mole
Mole of H2O = 5.91×10¯³ mole
Ratio of anhydrous CaSO4 to H2O =>
CaSO4 : H2O => 2.35×10¯³ /5.91×10¯³
CaSO4 : H2O => 1 : 3
Therefore, for 1 mole of the anhydrous CaSO4, there are 3 moles of H2O.
Therefore, the formula for the hydrate compound CaSO4.xH2O => CaSO4•3H2O.