Question

How many atoms of oxygen are in 8.43 g of magnesium sulfate heptahydrate (Epsom salts)?How many atoms of oxygen are in 8.43 g of magnesium sulfate heptahydrate (Epsom salts)?

Answer 1

Answer: The number of oxygen atoms in given amount of magnesium sulfate heptahydrate is $2.265\times 10^{23}$

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Given mass of magnesium sulfate heptahydrate = 8.43 g

Molar mass of magnesium sulfate heptahydrate = 246.47 g/mol

Putting values in above equation, we get:

$\text{Moles of magnesium sulfate heptahydrate}=\frac{8.43g}{246.47g/mol}=0.0342mol$

The chemical formula of magnesium sulfate heptahydrate is $MgSO_4.7H_2O$

1 mole of magnesium sulfate heptahydrate contains 1 mole of magnesium atoms, 1 mole of sulfur atoms, 11 moles of oxygen atoms and 14 moles of hydrogen atoms

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of particles

So, 0.0342 moles of magnesium sulfate heptahydrate will contain = $(11\times 0.0342\times 6.022\times 10^{23})=2.265\times 10^{23}$ number of oxygen atoms

Hence, the number of oxygen atoms in given amount of magnesium sulfate heptahydrate is $2.265\times 10^{23}$

Answer 2

Moles oxygen = 0.0338 x 11 =0.372
atoms oxygen = 0.372 x 6.02 x 10^23=2.24 x 10^23
moles water = 7 x 0.0338 =0.237