Q. Which of the following has the smallest number of molecules?
A) 0.1 mole of ${CO}_{2}$ gas
B) 11.2 L of ${CO}_{2}$ gas at STP
C) 22 g of ${CO}_{2}$ gas
D) $22.4 \times 10^{3}\$mL of ${CO}_{2}$ gas at STP
Explanation
(a)
(a) $0.1\ mole\ of\ {CO}_{2}$
(b) $\frac{11.2}{22.4} = 0.5\ mole\ of\ {CO}_{2}\$
(c) $\ \frac{22}{44} = 0.5\ mole\ of\ {CO}_{2}$
(d) $\frac{22.4 \times 10^{3}}{22400} = 1\ mole\ of\ {CO}_{2}$
Equal numbers of moles have equal number of molecules.
Hence, the smallest number of molecules of ${CO}_{2}\ is\ in\ 0.1\ mole\ of\ {CO}_{2}.$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.