An equilibrium mixture in a sealed vessel contains of , of , and some gas. If the active mass of is — Chemical Equilibrium Chemistry Question
Question
An equilibrium mixture in a $5\text{ L}$ sealed vessel contains $3.2\text{ g}$ of $O_2$, $X\text{ g}$ of $SO_2$, and some $SO_3$ gas. If the active mass of $O_2$ is found to be exactly equal to the active mass of $SO_2$ in this mixture, find the mass $X$ of $SO_2$ in grams. (Molar mass of $S=32$, $O=16$)
💡 Solution & Explanation
Since the vessel volume is the same ($5\text{ L}$) for both gases, equal active masses (molarities) mean equal number of moles. Moles of $O_2 = \frac{3.2}{32} = 0.1\text{ mol}$. Thus, moles of $SO_2$ must also be $0.1\text{ mol}$. Mass of $SO_2 = \text{moles} \times \text{molar mass} = 0.1 \times 64 = 6.4\text{ g}$.