A student forgot to add the reaction mixture to the round bottomed flask at 27°C but instead he/she placed the flask on the flame. After a lapse of time, he realized his mistake, and using a pyrometer he found the temperature of the flask was 477°C. What fraction of air would have been expelled out?

Question

Philoid · Accepted Answer

Given:

Initial temperature, T₁ =27°C = (27 + 273) K = 300K

Final temperature, T₂ = 477°C (477 + 273) K = 750K

Let the volume of the round bottomed flask be V.

Then, the volume of air inside the flask at 300K is, V₁ = V.

Let the volume of air inside the flask at 750K is = V₂

According to Charlee’s law we know that: -

(∵ V₁ = V)

∴ Volume of air expelled out = 2.5 V – V = 1.5 V

Hence, the fraction of the air expelled out is given by: -

∴ The fraction of the air expelled out is: 3/5.