Question

Two flasks A and B have equal volumes. Flask A contains hydrogen at 600K while flask B has same mass of $C{H}_4$ at 300 K. Then choose the correct option(s).

• A. In flask A, the molecules move faster than flask B.
• B. In flask B, the molecules move faster than flask A.
• C. Flask A contains greater number of molecules than flask B.
• D. Flask B contains more molecules than flask A.

Answer 1

Answer: (A), (C)

In flask A, the molecules move faster than flask B.
Flask A contains greater number of molecules than flask B.

The molecules having a larger value of $\frac{T}{M}$ will move faster than other molecules.
Hydrogen gas is at a higher temperature than methane. Also, hydrogen has a lower molecular weight than methane.
Hence, hydrogen molecules will move faster than methane.

The number of moles is the ratio of the mass of a substance to its molecular weight.
The molecular weight of hydrogen is lower than that of methane. The mass of the two gases is the same.
Thus, flask A contains more number of moles than flask B.
The number of molecules is directly proportional to the number of moles.
Thus, flask A contains more number of molecules than flask B.

Hence, the correct options are $\text{A}$ and $\text{C}$