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 shows that there is only one carbon atom in each molecule of dibromoethane. To calculate the number of moles of dibromoethane in 1.879 g, divide the mass by the molar mass: 
1.879 g / 187.9 g/mol = 0.01 mol 
Since there is one carbon atom in each molecule, there must be 0.01 mol of carbon atoms. Using Avogadro's number, we can convert to the number of atoms: 
0.01 mol x 6.022 x 10^23/mol = 1.204 x 10^22
Therefore, there are 1.204 x 10^22 carbon atoms in a sample of dibromoethane weighing 1.879 g.

The Molar Mass of the Insecticide Dibromoethane Is 187