Question

How many bromine atoms are present in 35.2 g of CH2Br2?

Answer 1

Because the symbol for bromine is Br and the make-up of the elements say that there are 2 bromine atoms, I'd assume that you would take 35.2 and multiply it by the 2 bromine atoms, resulting in 70.4 bromine atoms. But, I could very easily be wrong since I don't remember learning this in science.

Answer 2

2.44*10²³ Br atoms.

Step-by-step explanation:

To solve this problem we need to calculate the number of moles of CH₂Br₂ in 35.2 g.

• Molar mass of CH₂Br₂ = 12 + 1*2 + 2*79.9 = 173.8 g·mol⁻¹

35.2 g / 173.8 g·mol⁻¹ = 0.2025 mol CH₂Br₂

Now we use Avogadro's number to calculate the number of Br atoms in 0.2025 moles of CH₂Br₂, keeping in mind that there are 2 Br atoms for each CH₂Br₂ molecule:

0.2025 mol CH₂Br₂ *
`(6.023*10^(23)moleculesCH_(2)Br_(2))/(1molCH_(2)Br_(2)) *(2atomsBr)/(1moleculeCH_(2)Br_(2)) =` 2.44*10²³ Br atoms