M,CaCO3= (40gCa +12gC+3X16gO)/mol= 100g/mol
a) 40gCa
b) 1molCaCO3...are masa 100g .....contine 3molO
x.......................................6molO
x=mCaCO3=200g
c)M,CaCO3=100g/mol M,Na2CO3=106g/mol
100g CaCO3..................48gO 106gNa2CO3................48gO
100g.................................X 100g.............................................y
x= 48% O y=45,3%O