1. Understand the Formula

* C8H18 represents the chemical formula for octane, a type of hydrocarbon.

* It tells us that each molecule of octane contains 8 carbon atoms (C) and 18 hydrogen atoms (H).

2. Avogadro's Number

* Avogadro's number is a fundamental constant in chemistry: 6.022 x 10^23. It represents the number of entities (atoms, molecules, etc.) in one mole of a substance.

3. Calculate the Total Number of Hydrogen Atoms

* Step 1: Find the number of molecules in 2 moles of octane: 2 mol * 6.022 x 10^23 molecules/mol = 1.2044 x 10^24 molecules

* Step 2: Multiply the number of molecules by the number of hydrogen atoms per molecule: 1.2044 x 10^24 molecules * 18 H atoms/molecule = 2.168 x 10^25 H atoms

Therefore, there are approximately 2.168 x 10^25 hydrogen atoms in 2 moles of C8H18.