# What is the empirical formula of a compound that is 75% carbon and 25% hydrogen?

##### 1 Answer

#### Explanation:

For this kind of problem, you can assume that the weight of the unknown sample is 100g ( since 75%

Thus,

weight of

weight of

Since chemical formulas deal with number of moles rather than weight in grams, you need to convert each element by multiplying it to their respective atomic masses.

atomic mass of

atomic mass of

Thus,

mol

mol

Now we can see from the computation above that every

6.245 mol

Dividing both sides by the smallest number of moles, (in this case 6.245 mol

**1**

**4**

Therefore, empirical formula is