Question

Diphosphorus pentoxide(P2O5) reacts with water to form phosphoric acid, a major industrial acid. In the laboratory, the oxide is used as a drying agent. a.What is the mass of 4.65 x 10 22molecules of phosphorus pentoxide?

Answer 1

Answer: The mass of $4.65\times 10^{22}$ molecules of phosphorus pentoxide is 20.5 g

Explanation:

According to avogadro's law, 1 mole of every substance weighs equal to the molecular mass and contains avogadro's number $6.023\times 10^{23}$ of particles.

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given molecules}}{\text {avogadro's number}}=\frac{4.65\times 10^{22}}{6.023\times 10^{23}}=0.0772moles$

1 mole of $P_2O_5$ weigh =  283.9 g

Thus 0.0772 moles  of $P_2O_5$ weigh = $\frac{283.9}{1}\times 0.0722=20.5g$

Thus the mass of $4.65\times 10^{22}$ molecules of phosphorus pentoxide is 20.5 g