Question

a flask contain 4.4g of co2 gas calculate how many moles of co2 gas does it contain

Answer 1

44 g ( molecular mass) of co2 = 1 mole of co2
4.4 g of co2 = x mole of co2

x = 0.1 mole of CO2 gas

Answer 2

Atomic mass of carbon= 12u
Molar mass of C= 12g

Atomic mass of O2= 16u X 2     (∵ it is O2 in CO2)
                              ⇒ 32u
Molar mass of O2= 32g

Molar mass of CO2= Molar mass of C+Molar mass of O2
                               = 12g+32g
                               = 44g

No/. of moles= Given mass
                        ___________
                         Molar mass

                     = 44
                       ___      = 0.1
                        4.4    

∴  The number of moles of CO2 in flask is 0.1 mole.