Question

How many total atoms are in 0.650 g of P2O5?

Answer 1

N=N_A*n

n=m/M

M(P₂O₅) = 141.94 g/mol

n(P₂O₅) = 0.650 g/141.94g/mol = 0.00458 mol

N(P₂O₅) = 0.00458 mol * 6.022*10²³ mol^-1 = 2.76*10²¹ molecules

1 molecule of P₂O₅ contains 2+5 = 7 atoms

2.76*10²¹ molecules of P₂O₅ contain x atoms

1/2.76*10²¹ = 7/x

x= 1.93*10²² atoms

Answer: 1.93*10²²