1. Find the molar mass of benzene (C6H6):

* Carbon (C) has a molar mass of 12.01 g/mol

* Hydrogen (H) has a molar mass of 1.01 g/mol

* Molar mass of C6H6 = (6 * 12.01 g/mol) + (6 * 1.01 g/mol) = 78.12 g/mol

2. Calculate the moles of benzene in the sample:

* Moles = mass / molar mass

* Moles of C6H6 = 1.68 g / 78.12 g/mol = 0.0215 mol

3. Determine the moles of carbon atoms:

* Each mole of C6H6 contains 6 moles of carbon atoms.

* Moles of carbon = 0.0215 mol C6H6 * (6 mol C / 1 mol C6H6) = 0.129 mol C

Therefore, you can obtain 0.129 moles of carbon atoms from the decomposition of a 1.68 g sample of benzene (C6H6).