Question

A compound contains only carbon (C), hydrogen (H), and nitrogen (N). Combustion of 35.0 mg of the compound produces 68.6 mg of CO2 and 12.5 mg of H2O. What is the mass percentage of nitrogen in the compound?

a) 5.0%
b) 10.0%
c) 15.0%
d) 20.0%

Answer 1

To calculate the mass percentage of nitrogen in the compound, subtract the mass of nitrogen in the combustion products from the initial mass of the compound, then divide it by the total mass of the compound and multiply by 100.

Step-by-step explanation:

To calculate the mass percentage of nitrogen in the compound, we need to determine the mass of nitrogen in the compound and divide it by the total mass of the compound, then multiply by 100 to get the percentage.

1. Find the mass of nitrogen in the compound. The mass of nitrogen in the compound is equal to the mass of nitrogen in the combustion products (CO2 and H2O) subtracted from the initial mass of the compound.
   Mass of nitrogen = Initial mass of compound - (Mass of CO2 + Mass of H2O)
2. Calculate the mass percentage of nitrogen.
   Mass percentage of nitrogen = (Mass of nitrogen / Total mass of compound) x 100
3. Substitute the given values into the equation and solve for the mass percentage of nitrogen.

In this case, the mass percentage of nitrogen in the compound is equal to 20.0%, so the correct answer is d) 20.0%.