Question

How many oxygen atoms are there in 22.0 g of carbon dioxide? a) 1.42 x1024 b) 6.02 x1023 c) 1.20 x1024 d) 5.09 x1023 ​

Answer 1

• The Avogadro constant is 6.022140857 × 10²³

This tells you how many atoms you have in one mole.

So we have to find out how many moles there are in 22g of CO2.

• Number of moles =mass/molar mass

• Mass =22g
• Molar mass = relative atomic mass of carbon (12) + twice the relative atomic mass of oxygen (16) = 12 + (2 x 16) = 44.

Number of moles is 22/44 = 0.5 moles but there are two oxygens in the molecule so we actually will get 1 mole of oxygen from splitting the 22g of CO2 (0.5 x 2) for 2 oxygens in each molecule

1. Number of Oxygen atoms in 0.5 moles of CO2 = 1 x 6.022140857 × 10²³

So your number of oxygen atoms is 6.022140857 × 10²³