The mass of one mole of a substance in grams is called its …A… Here, A refers to — Mole Concept and Some Basic Concepts of Chemistry Chemistry Question

💡 Solution & Explanation

# Solution The mass of one mole of a substance in grams is called its **molar mass** (or molecular weight). **Step-by-step reasoning:** 1. **Definition of mole**: One mole contains $6.022 \times 10^{23}$ particles (Avogadro's number) 2. **Molar mass definition**: It is the mass in grams of exactly one mole of any substance - Units: g/mol 3. **Example**: - $H_2O$ has molar mass = $2(1) + 16 = 18$ g/mol - This means 1 mole of water weighs 18 grams 4. **Why "B" is correct**: The blank A refers to **molar mass** (or molecular mass/atomic mass depending on context) **Why other options would be wrong:** - Atomic mass: refers to mass of a single atom - Molecular mass: similar to molar mass but not expressed "in grams" per mole specifically - Equivalent mass: refers to mass that reacts/combines with 1 g of H The answer is **molar mass** or **molecular weight**.