**Passage 9:** **Hardness of water** is expressed in ppm (parts per million) as equivalents. A sampl — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

Question

**Passage 9:** **Hardness of water** is expressed in ppm (parts per million) as $CaCO_3$ equivalents. A $100 \text{ mL}$ sample of hard water contains $12 \text{ mg}$ of $MgSO_4$ (MW=120) and $11.1 \text{ mg}$ of $CaCl_2$ (MW=111). What are the **moles of $CaCO_3$ equivalent** to the $MgSO_4$ in the sample?