Question

CAlculate number of moles o CO2 which contains 8 g if O2

Answer 1

the mass of CO2 will be 11g if the O2 in it has a mass of 8g. 11g of CO2 will  have 1.505 into 10 to the power of 23 molecules 

Answer 2

In CO2 the constituents elements are in the ratio 3: 8 by weight

If it contains 3g of C

So total weight= 8+ 3 =11g

Calculate the molecular mass of CO2

Molecular mass = sum of atomic masses of constituents elements

Molecular mass=14+32

=44

no. of moles = total mass given/molecular mass

=11/44

=0.25