What is the molar mass (in g/mol) of ? (H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Ca = 40)
Answer and explanation
Correct answer: D. 18
- Step 1: To determine the molar mass of , sum the atomic masses of all constituent atoms in the chemical formula.
- Step 2: Substitute the standard atomic weights: 2(1) + 16 = 18\ \text{g/mol}.
- Step 3: The resulting sum yields a molar mass of 18\ \text{g/mol}.
Answer
18.
Why not the others: 20 adds 2 extra mass units; 16 accounts only for the single oxygen atom without hydrogen; 36 doubles the molecular weight.
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- What is the molar mass (in g/mol) of ? (H = 1, C = 12, N = 14, O = 16, Na = 23, S = 32, Ca = 40)