Question

question 1
3 pts
choose the gas that has the greatest average molecular speed at 25 °c.
he
xe
ne
cl₂
ar

Explanation:

According to the root - mean - square speed formula \(v_{rms}=\sqrt{\frac{3RT}{M}}\) (where \(R\) is the gas constant, \(T\) is the temperature, and \(M\) is the molar mass of the gas). At the same temperature (\(T = 25^{\circ}C\)), the smaller the molar mass \(M\) of the gas, the greater the root - mean - square speed (which is related to the average molecular speed). The molar masses are: \(M(He)=4\space g/mol\), \(M(Xe)=131.29\space g/mol\), \(M(Ne) = 20.18\space g/mol\), \(M(Cl_2)=70.90\space g/mol\), \(M(Ar)=39.95\space g/mol\). Since \(He\) has the smallest molar mass among these gases.

Answer:

He