What is the number of oxygen atoms in a 5.4 g sample of copper sulfate (2)?

Find the amount of copper sulfate substance.
M (CuSO4) = 64 + 32 + 4 × 16 = 160 g / mol.
We find the amount of substance.
n = m / M.
n (CuSO4) = 5.4 g / 160 g / mol = 0.03375 mol.
Next, we find the number of molecules using the following formula.
N = n × Na.
Na is Avogadro’s number equal to 6.02 × 10 ^ 23.
N = 0.03375 × 6.02 × 10 ^ 23 = 0.203275 = 20.3275 × 10 ^ 21.
Find the number of oxygen atoms in the copper sulfate compound.
N = 4 × 20.3275 × 10 ^ 21 = 4.0635 × 10 ^ 23
This means that the number of oxygen atoms is 4.0635 × 10 ^ 23.