Question

How many total atoms are in 0.700 g of P2O5?

Answer 1

1) Convert grams of P2O5 into moles of P2O5.

The molar mass of P2O5 is 141.9445 g/mol

`\text{mol of P}_2O_5=0.700gP_2O_5\cdot(1molofP_2O_5)/(141.94gP_2O_5)=0.004931molP_2O_5`

2) Convert moles into molecules

`\text{molecules of P2O5=0.004931 mol P2O5}\cdot\frac{6.02\cdot10^(23)\text{molecules}}{1\text{ mol P2O5}}=2.968\cdot10^(21)\text{molecules of P2O5}`

3) Convert molecules into atoms

`numberofatoms=2.968\cdot10^(21)\text{molecules of P2O5}\cdot\frac{7\text{ atoms}}{1\text{ molecule }}=2.0779\cdot10^(22)\text{ atoms}`

There are 2.0779*10^22 atoms in 0.700 g of P2O5.