1. Determine the Molecular Formula of Styrene

Styrene has the molecular formula C₈H₈.

2. Calculate the Molar Mass of Styrene

* Carbon (C): 8 atoms * 12.01 g/mol = 96.08 g/mol

* Hydrogen (H): 8 atoms * 1.01 g/mol = 8.08 g/mol

* Total Molar Mass: 96.08 g/mol + 8.08 g/mol = 104.16 g/mol

3. Convert the Mass of Styrene to Moles

* Moles = Mass / Molar Mass

* Moles of styrene = 5.905 g / 104.16 g/mol = 0.0567 mol

4. Calculate the Number of Hydrogen Atoms

* Since there are 8 hydrogen atoms in one molecule of styrene, there are 8 times as many hydrogen atoms as there are molecules of styrene.

* Number of hydrogen atoms = 0.0567 mol styrene * (8 atoms H / 1 molecule styrene) * (6.022 x 10²³ molecules/mol)

* Number of hydrogen atoms = 2.73 x 10²³ atoms

Therefore, there are approximately 2.73 x 10²³ hydrogen atoms present in a 5.905 g sample of styrene.