As Chem question

Oxygen, O2 can be converted into ozone, O3, by passing it through an electric discharge.

3O2 —> 2O3

In an experiment, a volume of 300cm3 of oxygen was used but only 10% of the oxygen was converted into ozone. All volumes were measured at RTP. What was the total volume of had present at the end of the experiment in cm3.

I keep getting an answer of 200 when the answer is 290. Can someone walk me through it?

(edited 4 years ago)

Reply 1

Pintotechie

Original post by Anonymous__02

I think this may help you
3O2 —> 2O3
300 cm3 of oxygen is used, but only 10% of the oxygen was converted to Ozone gas.
10% of 300cm3 = 30cm3
From the balanced chemical equation, take the mole ratio if Oxygen: Ozone, they are reacting in the mole ratio of 3:2,
Here is the trick, Volume ratio will also be the same, due to the reason that the volume of gases measured is at
the same temperature.
so 3:2 is taken as 30cm3: 20cm3 as oxygen is to the Ozone ratio of volumes.
only 20 cm3 of oxygen has reacted from 300 cm3 of oxygen, leftover unreacted oxygen is [300]
The total volume of gases at end of the experiment :

Unreacted Oxygen left = 270 cm3
The volume of Ozone gas formed = 20 cm3
The summation of the Total = 290 cm3

There u go, the answer to this question
Answered by Pintotechie from INTERNATIONAL TRAINING INSTITUTE, DUBAI, UNITED ARAB EMIRATES
HOD OF SCIENCE

Reply 2

Pintotechie

From the balanced chemical equation, take the mole ratio of Oxygen: Ozone, they are reacting in the mole ratio of 3:2,
Here is the trick, Volume ratio will also be the same, due to the reason that the volume of gases measured is at
the same temperature.
so 3:2 is taken as 30cm3: 20cm3 as oxygen is to the Ozone ratio of volumes.
only 20 cm3 of oxygen has reacted from 300 cm3 of oxygen, leftover unreacted oxygen is [300]
The total volume of gases at the end of the experiment :

Unreacted Oxygen left = 270 cm3
The volume of Ozone gas formed = 20 cm3
The summation = 290 cm3

There u go, the answer to this question
Answered by Pintotechie from INTERNATIONAL TRAINING INSTITUTE, DUBAI, UNITED ARAB EMIRATES
HOD OF SCIENCE