34.00 ~~mL~~ C6H6 x | 0.880 ~~g~~ |1 ~~mol C6H6~~|6.022 x 10^{23} molecules|

| 1 ~~mL C6H6~~ | 78.11 ~~g~~ | 1 ~~mol C6H6~~ |

Carry this out and you would end up with 3.291 x 10^{17}molecules.

*Note* I did this on my computer calculator, so this arithmetic may be incorrect