How much oxygen will contain the same number of atoms as the number of molecules in 73 g of HCI?

64g of O2.

Explanation:

We'll begin by calculating the number of molecules in 73g if HCl.

This is illustrated below:

From Avogadro's hypothesis, we understood that 1 mole of any substance contains 6.02×10²³ molecules. This implies that 1 mole of HCl also contains 6.02×10²³ molecules

1 mole of HCl = 1 + 35.5 = 36.5g

Thus, if 36.5g of HCl contains 6.02×10²³ molecules, then 73g of HCl will contain = (73 x 6.02×10²³)/36.5 = 1.204×10²⁴ molecules.

Therefore, 73g of HCl will contains 1.204×10²⁴ molecules.

Now, we shall determine the mass of oxygen that will contain 1.204×10²⁴ molecules.

This can be obtained as follow:

1 mole of O2 = 16x2 = 32g

32g of O2 contains 6.02×10²³ molecules.

Therefore, Xg of O2 will contain 1.204×10²⁴ molecules i.e

Xg of O2 = (32 x 1.204×10²⁴)/6.02×10²³

Xg of O2 = 64g

Therefore, 64g of O2 will contain the same number of molecules (i.e 1.204×10²⁴ molecules) in 73g of HCl.