Calculate the mass of 2×10^23 molecules of nitric acid

1.	Calculate the mass of 2×10^23 molecules of nitric acid
Answer» We know that,No. of moles =Total no. of molecules/Avogadro no.Therefore,no. of moles of nitric acid(HNO3)=210^23/610^23.=1/3 moles...(We have approximated 6.02210^23 as 610^23 to solve the problem easily)Now,we know that no.of moles=given mass/molar mass Let x be the given mass of nitric acid.Molar mass of nitric acid=63Substituting the values,we get,1/3=x/63Therefore,x=21g

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