calculate the mass of 4.515*1o^23 molecules of oxygen

Question

anonymous · Answer

My answer is 12 ..is it Right?? :/

thomaster · Answer

First calculate the amount of moles oxygen.
So divide the number of molecules by Avogadro's number $(6.022*10^{23})$
When you have the amount of moles you can calculate the mass by multiplying the moles with the molecular weight of oxygen (15.999 g/mol)

chmvijay · Answer

6.023 *10^23 molecules of O2 are present in 1mole (16g )of O2
then4.515 *10^23 molecules of O2 are present in = 16 * 4.515*10^23   / 6.023*10^23 
                                                                                = 12 is right answer