What is the molar mass of MgO? (H = 1, C = 12, N = 14, O = 16, Na = 23, Mg = 24, Al = 27, S = 32, Cl = 35.5, K = 39, Ca = 40, Mn = 55, Fe = 56)
Answer and explanation
Correct answer: C. 40 g/mol
- Step 1: Add the atomic masses of all the atoms in the formula. Step 2. MgO: 24 + 16 = 40 g/mol. Answer: 40 g/mol. Why not the others: 106 g/mol is what you get if you use the molar mass of Na₂CO₃. 95 g/mol is what you get if you use the molar mass of MgCl₂. 18 g/mol is what you get if you use the molar mass of H₂O.
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