Consider the precise mass measurements of the following microscopic and macroscopic samples. Which o — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question
Question
Consider the precise mass measurements of the following microscopic and macroscopic samples. Which of the following statements correctly order them in strictly increasing mass? (Atomic weights: $N = 14\text{ u}$, $O = 16\text{ u}$, $Cu = 63.5\text{ u}$) (I) 1 independent molecule of Oxygen ($O_2$) (II) 1 individual atom of Nitrogen ($N$) (III) $1.0 \times 10^{-10}\text{ moles}$ of Oxygen gas ($O_2$) (IV) $1.0 \times 10^{-10}\text{ moles}$ of Copper solid ($Cu$)
💡 Solution & Explanation
Calculate the absolute mass of each sample in grams. (I) 1 molecule of $O_2 = 32\text{ amu} = 32 \times 1.66 \times 10^{-24}\text{ g} \approx 5.31 \times 10^{-23}\text{ g}$. (II) 1 atom of N = $14\text{ amu} = 14 \times 1.66 \times 10^{-24}\text{ g} \approx 2.32 \times 10^{-23}\text{ g}$. (III) $1.0 \times 10^{-10}\text{ moles}$ of $O_2 = 10^{-10} \times 32\text{ g/mol} = 3.2 \times 10^{-9}\text{ g}$. (IV) $1.0 \times 10^{-10}\text{ moles}$ of Cu = $10^{-10} \times 63.5\text{ g/mol} = 6.35 \times 10^{-9}\text{ g}$. Increasing order of mass: (II) < (I) < (III) < (IV). Option A: (I) > (II) is True. Option B: (III) < (IV) is True. Option C: (IV) < (II) is False. Option D: (II) is the lightest is True.