A compound is isolated from the rind of lemons that is found to be 88.14% carbon and 11.86% hydrogen by mass. What is the empirical formula?

When calculating an empirical formula the size of the sample does not matter, so I'm going to make the calculations simpler:

Take a hypothetical sample of exactly 100 grams of the compound:

(88.14 g C) / (12.01078 g C/mol) = 7.338 mol C

(11.86 g H) / (1.007947 g H/mol) = 11.77 mol H

Divide by the smaller number of moles:

(7.338 mol C) / 7.338 mol = 1.000

(11.77 mol H) / 7.338 mol = 1.604

In order to achieve integer coefficients, multiply by 5, then round to the nearest whole numbers to find the empirical formula:

C5H8

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You didn't ask, but this empirical formula and the clue about lemon rind and the coincidence of the name Limonene (C10H16 , MW = 136.234 g/mol) makes me think that is the compound you're asking about.