Question
Tue April 15, 2014 By: Yash Sahu

Equal masses of oxygen (O2) and ozone (O3) are taken seperately. choose the correct alternatives .(there are more than one correct)

(A)they contain equal number of oxygen atoms .

(B)they contain equal number of oxygen molecules.

(C) they occupy different volumes ( seperately)under the same conditions of temperature and pressure.

(D)under the same conditions of temperatures and pressure volume occupied by O2 and O3 are in 3:2 ratio . 

Expert Reply
Thu April 17, 2014
Option (C) and (D).

1 mole of O2  = 32g

? moles of O2 = 1g

1 x 1/32 = 0.0312 moles = n1  ---------------------(1)

1 mole of O3  = 48g

? moles of O3 = 1g

1 x 1/48 = 0.0208 moles = n2  ---------------------(2)

So numbers of moles are different.

Solution for Option (C)

They occupy different volumes under the  same conditions of temperature and pressure.

PV = n RT  --------------------------------------------(3)

So V = n RT/P

When we calculate volume P, R and T will remain constant. But since number of moles are different so volumes of O2 and O3 will be different.

 

Solution for option (D)

Under the same conditions of temperature and pressure volume occupied by O2 and O3 are in the ratio 3:2.

Since P, R and T are constant.

So equation (3) can be written as follows

V1/V2 = n1/n2

V1/V2 = 0.0312/0.0208

Multiplying the equation by 100

V1/V2 = 3/2

So the ratio is 3:2

 

 

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