Question

What is the percent by mass of carbon in C10 H14 N2?

Answer 1

Multiply the number of each element by its mass on the periodic table.

Add them together.

Put the mass of carbon only over the total mass and multiply the result by 100 to get the percentage.

Answer 2

Answer: The percentage by mass of carbon in the given compound is 45.8 %

Explanation:

We are given a chemical compound having chemical formula $C_{10}H_{14}N_2$

To calculate the percentage composition of an element in a compound, we use the equation:

$\%\text{ composition}=\frac{\text{Mass of carbon element}}{\text{Mass of compound}}\times 100$

In 1 mole of given compound, 10 moles of carbon atoms are there.  

Mass of $C_{10}H_{14}N_2= [(10\times 12)+(14 \times 1)+(2\times 14)]=262g/mol$

Mass of carbon element = $[10\times 12]=120g/mol$

Putting values in above equation, we get:

$\%\text{ composition of carbon}=\frac{120}{262}\times 100=45.8\%$

Hence, percentage of carbon in given compound is 45.8 %.