A compound that is composed of only carbon and hydrogen contains 80.0% C and 20.0% H by mass.What is the empirical formula of the compound? A)C₂₀H₆₀ B)C₇H₂₀ C)CH₃ D)C₂H₆ E)CH₄

Question

Quizplus · Accepted Answer

To find the empirical formula, we need to determine the ratio of atoms present in the compound. We can assume a 100g sample of the compound, which means 80g is carbon and 20g is hydrogen.

Then, we can convert the mass to moles using the atomic weights:
- 80g C = 6.67 moles C
- 20g H = 19.76 moles H

Next, we find the simplest whole number ratio by dividing both by the smallest mole value (in this case, 6.67 moles C):

- 6.67 moles C / 6.67 = 1.00 mol C
- 19.76 moles H / 6.67 = 2.96 mol H

Thus, the empirical formula is CH1.00, which we can round to simply CH.

The other answer choices have different ratios of carbon to hydrogen and do not match the given percentages.

A Compound That Is Composed of Only Carbon and Hydrogen