The number of molecules in 48.0 grams of oxygen gas (O2) is... O 6.02 x 1023
O 1.81 x 1024
O 1.20 x 1024
9.03 x 1023

9.033 × 10²³ molecules

Explanation:

Given data:

Mass of oxygen = 48.0 g

Number of molecules = ?

Solution:

Number of moles of oxygen:

Number of moles = mass/molar mass

Number of moles = 48.0 g/ 32 g/mol

Number of moles = 1.5 mol

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.  The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ molecules

1.5 mol  × 6.022 × 10²³ molecules  / 1mol

9.033 × 10²³ molecules