A compound contains carbon, hydrogen, and nitrogen as its only elements. A 9.353 g sample of the compound contains 5.217 g of carbon and 1.095 g of hydrogen; the remainder of the mass is nitrogen. What is the empirical formula of the compound? Hint: Use moles to relate the mass of one element to another.

Question

Quizplus · Accepted Answer

The empirical formula is C3H7N.To find the empirical formula, we need to determine the mole ratio of each element in the compound.The molar mass of carbon is 12.01 g/mol, the molar mass of hydrogen is 1.008 g/mol, and the molar mass of nitrogen is 14.01 g/mol.The number of moles of carbon in the sample is 5.217 g / 12.01 g/mol = 0.434 mol.The number of moles of hydrogen in the sample is 1.095 g / 1.008 g/mol = 1.086 mol.The number of moles of nitrogen in the sample is (9.353 g - 5.217 g - 1.095 g) / 14.01 g/mol = 0.228 mol.The mole ratio of carbon to hydrogen to nitrogen is 0.434 : 1.086 : 0.228, which simplifies to 3 : 7 : 1.Therefore, the empirical formula of the compound is C3H7N.

A Compound Contains Carbon, Hydrogen, and Nitrogen as Its Only