AP EAMCET202125 Aug 2021Evening ShiftChemistryStates of MatterActual
Among the following, identify the gas which has the greatest average speed of its molecules?
Options
- A0.5 ~mol of O ₂ at 500 ~K
- B0.2 ~mol ^2 CO ₂ at 400 ~K
- C1.0 ~mol of He at 200 ~K
- D0.4 ~mol of NH ₃ at 300 ~K
Correct answer
C. 1.0 ~mol of He at 200 ~K
Step-by-step solution
The average molecular speed is inversely proportional to the square root of molar mass. v= 8 R T M i.e. v 1 M Among O ₂, CO ₂ , He and NH ₃ , He has very low molar mass. Therefore, it has greatest average velocity. Order of molar mass ( g / mol ) is array ccc CO ₂> & O ₂ He 44.01 & 32.0 & 17.03 array Order of average velocity is He > NH ₃> O ₂> CO ₂ . Hence, helium has the greatest average speed of its molecules.