A compound that is composed of only carbon and hydrogen contains 85.7% C and 14.3% H by mass. What is the empirical formula of the compound? A) CH₄ B) C₂H₄ C) CH₂ D) C₈₆H₁₄ E) C₄H₈

Question

Quizplus · Accepted Answer

To find the empirical formula of a compound, we use the mass percentages of each element to determine the relative number of atoms in the compound.

Assume we have 100g of the compound: 
- 85.7 g is carbon 
- 14.3 g is hydrogen

Next, we need to convert the mass of each element to moles:
- Carbon: 85.7 g / 12.01 g/mol = 7.14 moles
- Hydrogen: 14.3 g / 1.01 g/mol = 14.2 moles

Now we need to divide each of these by the smallest of the two (which is carbon):
- Carbon: 7.14 moles / 7.14 moles = 1
- Hydrogen: 14.2 moles / 7.14 moles = 1.99

We can round this to the nearest whole number, which gives us 2 for hydrogen.

Therefore, the empirical formula is CH2.

A Compound That Is Composed of Only Carbon and Hydrogen