Question

rical formula for the compound.A gaseous hydrocarbon (a compound that contains only hydrogen and carbon) is found to be 11 % hydrogen by mass. a. Find the empirical formula for the compound.

Answer 1

Answer: The empirical formula will be=$C_2H_3$

Explanation:

If percentage are given then we are taking total mass is 100 grams.

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

Mass of C= (100-11) = 89 g

Mass of H = 11 g

Step 1 : convert given masses into moles.

Moles of C =$\frac{\text{ given mass of C}}{\text{ molar mass of C}}= \frac{89g}{12g/mole}=7.4moles$

Moles of H =$\frac{\text{ given mass of H}}{\text{ molar mass of H}}= \frac{11g}{1g/mole}=11moles$

Step 2 : For the mole ratio, divide each value of moles by the smallest number of moles calculated.

For C = $\frac{7.4}{7.4}=1$

For H = $\frac{11}{7.4}=1.5$

The ratio of C : H: = 1: 1.5

Convertig them into whole number ratios

The ratio of C : H: = 2: 3

Hence the empirical formula is $C_2H_3$

The empirical formula will be=$C_2H_3$