Question

An unknown compound has the following chemical formula:
P2Ox

where x stands for a whole number. Measurements also show that a certain sample of the unknown compound contains 8.20 mol of oxygen and 3.3 mol of calcium. Write the complete chemical formula for the unknown compound.

Answer 1

Answer:

The chemical formula of the compound is $P_2O_5$.

Explanation:

In 1 mole of $P_2O_x$ there are 2 moles of phosphorus atom.

Then 3.3 moles of phosphorus will be in :

$\frac{1}{2}\times 3.3 mol=1.65 moles$

In 1 mole of $P_2O_x$ there are x moles of oxygen atom.Then 1.65 moles of compound will have :

$1.65 mol\times x$

Moles of oxygen in 1.65 moles of compound = 8.20 mol

$1.65 mol\times x=8.20 mol$

$x=\frac{8.20 mol}{1.65 mol}=4.9 \approx 5$

The chemical formula of the compound is $P_2O_5$.