Question

DDT is used as an insecticide; its molar mass is 354.5 g/mol. When DDT was analyzed by a chemist, he found that it contains 47.4% carbon. How many carbon atoms are there in DDT?

a) 5.61 x 10²3
b) 6.02 x 10²3
c) 7.20 x 10²3
d) 8.10 x 10²3

Answer 1

To determine the number of carbon atoms in DDT, calculate the number of moles of carbon in a sample of DDT and then convert that to the number of atoms. The molar mass of DDT is 354.5 g/mol and it contains 47.4% carbon. Therefore, there are approximately 2.374 x 10^24 carbon atoms in DDT.

Step-by-step explanation:

To determine the number of carbon atoms in DDT, we need to calculate the number of moles of carbon in a sample of DDT and then convert that to the number of atoms. The molar mass of DDT is 354.5 g/mol and it contains 47.4% carbon. This means that in 100 g of DDT, there are 47.4 g of carbon.

To calculate the number of moles of carbon, we divide the mass of carbon by the molar mass of carbon (12.01 g/mol):

(47.4 g) / (12.01 g/mol) = 3.946 mol of carbon

Next, we use Avogadro's number (6.02 x 10^23 atoms/mol) to convert the moles of carbon to the number of carbon atoms:

(3.946 mol) * (6.02 x 10^23 atoms/mol) = 2.374 x 10^24 carbon atoms

Therefore, there are approximately 2.374 x 10^24 carbon atoms in DDT.