The molar mass of the insecticide dibromoethane is 187.9 g/mol. Its molecular formula is C₂H₄Br₂. How many atoms of carbon are in a sample of dibromoethane weighing 1.879 g?

Question

Quizplus · Accepted Answer

The molecular formula of dibromoethane shows that it contains one carbon atom (C1). Therefore, the number of moles of dibromoethane in 1.879 g is:
moles = mass/molar mass
moles = 1.879 g/187.9 g/mol = 0.01 mol
Since there is one carbon atom in one molecule of dibromoethane, there must be 0.01 mol of carbon atoms in 0.01 mol of dibromoethane. Therefore, the number of carbon atoms in 1.879 g of dibromoethane is:
number of carbon atoms = moles of carbon atoms x Avogadro's number
number of carbon atoms = 0.01 mol x 6.022 x 10^23 mol^-1 = 1.204 x 10^22

The Molar Mass of the Insecticide Dibromoethane Is 187