Question

For sulphur dioxide calculate mass of 2.8 moles and 280 molecules

Answer 1

To calculate mass of 2.8 moles and 280 molecules
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hence
Molecular mass of 1 molecule = S + 2×O

=32 + 2× 16

=32 + 32

= 64g
so,as we know
one mole of any substance contains 6.022×10^23 molecules

show 2.8 mole of that substance will contain = 6.022×10^23 × 2.8

=17.4616 × 10^23 molecules

=1.74616 × 10^24 molecules

but here it is asked for 2.8 mole + 280 molecules )

so,

the total number of molecules = (1.74616×10^24+ 280)

= (174.616×10^22+ 280)

= 1.74616×10^24 molecules

so,mass of 1.74616×10^24 molecules

= 64× 1.74616× 10^24 g

= 1.1175424× 10^26 g

mass are present