Moles-working out no of moles present?

Determine the number of moles of of Na2CO3


present in 400 g.





Is there 1 mole each of NA and CO?


from there,how would i work it out?

Moles-working out no of moles present?
n(Na2CO3)=mass / Molar mass


= 400 / 105.989


= 3.77 mol





n(Na) = 2 x n(Na2CO3)


= 2 x 3.77


= 7.54 mol





n(CO3) = 3 x n(Na2CO3)


= 3 x 3.77


= 11.31 mol
Reply:what you do first is figure out what the molar mass of Na2CO3 is:





Na2: 2(22.99g/mol)=45.98g/mol


C: 12.01g/mol


O3: 3(16.00g/mol)= 48.00g/mol


________________________


Na2CO3: 105.99g/mol





use the # grams in sample and divide by the molar mass of Na2CO3





400g/(105.99g/mol)


or 400g x mol/105.99g





grams cancel out and you're left with moles





= 3.77394....moles


=3.77 moles correct to 3 significant digits