Question

How many total atoms are in 0.220 g of p2o5?

Answer 1

To determine the number of total atoms in 0.220 g of P2O5, calculate the moles of P2O5 using its molar mass and then multiply by Avogadro's number and the number of atoms per molecule of P2O5.

Step-by-step explanation:

To calculate how many total atoms are in 0.220 g of P2O5, we must first determine the number of moles of P2O5 that corresponds to the given mass. The molar mass of P2O5 is the sum of the atomic masses of its constituent atoms, which is 2P + 5O. Using the masses given:

• 2P: (2 atoms) (30.973761 amu/atom) = 61.947522 amu
• 5O: (5 atoms) (15.9994 amu/atom) = 79.997 amu

Summing these gives the molar mass of P2O5: 61.947522 amu + 79.997 amu = 141.944522 amu. To find the moles of P2O5 in 0.220 g, we use the formula:

Moles of P2O5 = mass in grams / molar mass

Moles of P2O5 = 0.220 g / 141.944522 g/mol

Now, to find the number of total atoms:

Total atoms = moles of P2O5 × Avogadro's number × atoms per molecule of P2O5

P2O5 contains 2 phosphorus atoms and 5 oxygen atoms, making 7 atoms per molecule. Therefore, the total number of atoms in the given mass of P2O5 will be the product of the number of moles, Avogadro's number (6.022 × 1023 atoms/mol), and 7.

Answer 2

From the periodic table:
molecular mass of P = 30.9 grams
molecular mass of O = 16 grams
Therefore:
molar mass of P2O5 = 2(30.9) + 5(16) = 141.8 grams

Number of moles = mass / molar mass = 0.22/141.8 = 1.55 x 10^-3 moles

One mole of any substance contains Avogadro's number of atoms. Therefore, number of atoms in 1.55 x 10^-3 moles is:
1.55 x 10^-3 x 6.022 x 10^-3 = 9.34 x 10^20 atoms