find number of molecules

Question

calculate number of molecules in 9g of CO2

Answer 1

Hello Binte

 

First, you need to convert the mass of CO₂ in grams to moles using its molar mass (44 g/mol).

 

9 g CO₂ x (1 mol CO₂ / 44 g CO₂) = 0.2 mol CO₂

 

Then use avogadro's # as a conversion factor to calculate the # of molecules.

 

1 mole = 6.02 x 10²³ molecules

 

0.2 mol CO₂ x (6.02 x 10²³ molecules CO₂ / 1 mol CO₂) = 1 x 10²³ molecules CO₂

Answer 2

g  ->  moles -> molecules

9 g x 1 mole CO₂/44 g = 0.205 moles CO₂

0.205 moles CO₂ x 6.02x10²³ molecules/mole = 1.2x10²³ molecules of CO₂