Question

How many molecules are there in 1 g of chlorine? ( atomic mass =35.5)

Answer 1

The atomic mass of chlorine is 35.5 g.

as we know that

No. of Moles = mass in grams/ Atomic mass

by putting values

1 mol = mass in grams/ 35.5

mass in grams = 35.5 g

grams of chlorine in one mole = 35.5 g

first need to calculate moles

No. of Moles = 1 g / 35.5 g/mol

No. of Moles = 0.0281 mol

The formula for calculating the number of molecules :

Number of molecules = No. of Moles X Avogadro's number

Number of molecules = 0.0281 X 6.022 X 10²³

Number of molecules = 0.169 X 10²³ molecules

$\therefore$ molecules of chlorine in 1 g of chlorine = 0.169 X 10²³ molecules