hello s r,

As we know that,

Mass of Sulphuric (H2SO4) = 0.49g

We have the number of molecules in 0.49g of H2SO4

Molecular mass of H2SO4 = (Atomic mass of H) x 2 + (Atomic mass of S) x 1 + (Atomic mass of O) x 4

Molecular mass of H2SO4 = ( 1 x 2) + (32 x 1) + (16 x 4)

= 2 + 32 + 64

= 98.


Now,

According to the formula,

Number of moles in the given H2SO4(n)

= Mass of H2SO4 in grams/Molecular mass of H2SO4

= 0.49/98

= 0.01/2

= 0.005

: n = 0.005 mol


: 1 mol of H2SO4 contains 6.022 x 10^23 molecules.


: 0.005 mol of H2SO4 contains 0.005 x 6.022 x 10^23 molecules.


= 0.003011 x 10^23 molecules .


that is 0.49 g of H2SO4 contains 0.003011 x 10^23 molecules of H2SO4.
hope this will help you lot.

Hi,

Your question is based on the concept of molarity. Now, you must be aware that that the molar mass of H2SO4 is 98. We will now calculate number of moles:

m=0.49g

M=98g/mol

Number of moles= given mass/ total mass

n= 0.49/98= 0.005 moles

Now, we have total number of moles, to get the number of molecules in 0.49 grams, we mill multiply number of moles by the avogadro number

I hope this helped you.