**Passage 7:** **Oleum** is a mixture of and free . It is labeled as , where is the mass of water re — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

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**Passage 7:** **Oleum** is a mixture of $H_2SO_4$ and free $SO_3$. It is labeled as $(100 + x)\%$, where $x$ is the mass of water required to react with all free $SO_3$ in $100\text{ g}$ of oleum to form $H_2SO_4$. For a sample of **$109\%$ oleum**, how many moles of water are required for $100\text{ g}$ of the sample?