Question

If 6×10^20 molecules of SO2 are removed from 320 mg of SO2 then find the no. of molecules remaining.

Answer 1

Number of molecules remaining when A amount is removed from it.
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As we know one mole of any substance contain the number of molecules = 6.022× 10^23

So,
1 mole of Sulphur dioxide will also contain = 6.022× 10^23 molecules.

Now for it,
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we have to calculate the mass of 1 mole of Sulphur dioxide,

Firstly mass of One molecule

=== S + 2 [O] = 32 + 2 [16]

= 32 + 32

= 64 g

As 320 gram of Sulphur dioxide removed.
So number of moles of Sulphur dioxide removed,

(n) =
Weight of sulphur /molecular mass of Sulphur

(n) = .32/ 64

= .005 mole
So remaining moles of Sulphur dioxide

= 1. - 0.005

= 0.995 mole
As one mole contains number of molecules = 6.022× 10^23

So Number of molecules remaining

= 0.995 × 6.022× 10^23

= 5.991 × 10^23 molecules

Thus 5.991 × 10^23 molecules remaining.

Answer 2

Answer:

Correct option is A)

Explanation:

32g of O

2

=1mol=6.023×10

23

molecules

∴320mg=0.32g=0.01mol=6.023×10

21

From this 6.023×10

20

moles are removed= 0.001 moles

∴ Remaining= 0.01−0.001=0.009 moles

=9×10

−3

moles .