Question

a hydrocarbon contains 91.3% c by mass . find the empirical formula of the hydrocarbon

Answer 1

hope this answer will help

Answer 2

Answer: The empirical formula for the given compound is CH.

Explanation:

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting percentages into mass

Total mass of the hydrocarbon is taken as 100 g.

So, the mass of each element is equal to the percentage given.

Mass of Carbon = 91.3 g

Mass of Hydrogen = [100 - 91.3] = 8.7 g

Step 2: Converting the given masses into moles.

Moles of Carbon =$\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{91.3g}{12g/mole}=7.60moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{8.7g}{1g/mole}=8.7moles$

Step 3: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 7.60 moles.

For Carbon = $\frac{7.60}{7.60}=1$

For Hydrogen  = $\frac{8.7}{7.60}=1.14\approx 1$

Step 4: Taking the mole ratio as their subscripts.

The ratio of C : H = 1 : 1

Hence, the empirical formula is CH.