Question

Calculate the number of O atoms in 0.150 g of CaSO4 · 2H2O.

Answer 1

Answer:

There are 0.00523 moles of oxygen in 0.150 grams of calcium sulfate crystal.

Explanation:

Mass of calcium sulfate crystal = m = 0.150 g

Molar mass of calcium sulfate crystal = M = 172 g/mol

Moles of magnesium nitrate = n

$n=\frac{m}{M}$

$n=\frac{0.150 g}{172 g/mol}=0.0008721 mol$

1 mole of calcium sulfate crystal has 6 moles of oxygen atoms. Then 0.004446 moles calcium sulfate crystal will have :

$6\times 0.0008721 mol=0.0052326mol\approx 0.00523 mol$

There are 0.00523 moles of oxygen in 0.150 grams of calcium sulfate crystal.