Answer: 4.4 × 10^20 mol
Step-by-step explanation:
First step, is to find the molar mass of the compound by finding each molar mass of each element in the compound and if they have a number of moles next to the element symbol you have to make sure to multiply that specific element by that number of moles and then add all of the elements molar masses together to find the molar mass of the compound ( molar masses of elements are found on the periodic table).
H3 = 1.01 g × 3 = 3.03 g,
P = 30.97 g,
O4 = 16.00 g × 4 = 64.00 g
3.03 g + 30.97 g + 64.00 g = 98.00 g
H3PO4 = 98.00 g/mol
Second step, is to find the moles of the compound by multiplying the molar mass by Avogadro's number (6.022 × 10^23 g/mol) so that the grams canceled and leaves you with the moles.
98.00 g × 1 mol ÷ 6.022 × 10^23 g = 1.62736632 × 10^-22 mol of H3PO4
Third step, is to find the moles of the molecules by multiplying Avogadro's number again to the given molecules
(4.3 × 10^22 molecules).
4.3 × 10^22 molecules × 1 mol ÷ 6.022 × 10^23 molecules = 0.0714048489 mol
Fourth step, you divide the moles of the molecules by the moles of the compound, to find the moles of the molecules in the compound.
0.0714048489 mol ÷ 1.62736632 × 10^-22 mol H3PO4 = 4.387755112 × 10^20 mol
Fifth step, depending on the significant figures you have, you round the final answer to the significant figures you need in this case 2 significant figures found by the first number given which was the molecules.
4.4 × 10^20 mol