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.

Answer 2

In 0.150 g of CaSO₄·2H₂O, there are 3.15 × 10²¹ O atoms.

We want to calculate the number of oxygen atoms in 0.150 g of CaSO₄·2H₂O. We will need a series of conversion factors.

What is a conversion factor?

A conversion factor is an arithmetical multiplier for converting a quantity expressed in one set of units into an equivalent expressed in another.

We will need to consider the following conversion factors:

• The molar mass of CaSO₄·2H₂O is 172.17 g/mol.
• There are 6.02 × 10²³ molecules of CaSO₄·2H₂O in 1 mole (Avogadro's number).
• There are 6 oxygen atoms in 1 molecule of CaSO₄·2H₂O.

$0.150 g CaSO_4.2H_2O \times \frac{1molCaSO_4.2H_2O}{172.17gCaSO_4.2H_2O} \times \frac{6.02\times 10^{23}moleculesCaSO_4.2H_2O }{1molCaSO_4.2H_2O} \times \frac{6\ O\ atoms}{1moleculeCaSO_4.2H_2O} = \\ = 3.15 \times 10^{21} O\ atoms$

In 0.150 g of CaSO₄·2H₂O, there are 3.15 × 10²¹ O atoms.

Learn more about Avogadro's number here: https://brainly.com/question/7287712