What is the formula mass of anhydrous sodium carbonate? (Given that the atomic masses of sodium, carbon and oxygen are 23 u, 12 u and 16 u respectively)
[amp_mcq option1=”286 u” option2=”106 u” option3=”83 u” option4=”53 u” correct=”option2″]
This question was previously asked in
UPSC NDA-2 – 2018
– The formula mass is the sum of the atomic masses of all atoms in the formula unit.
– Atomic masses given: Sodium (Na) = 23 u, Carbon (C) = 12 u, Oxygen (O) = 16 u.
– Formula mass of Na₂CO₃ = (2 × Atomic mass of Na) + (1 × Atomic mass of C) + (3 × Atomic mass of O)
– Formula mass = (2 × 23 u) + (1 × 12 u) + (3 × 16 u)
– Formula mass = 46 u + 12 u + 48 u = 106 u.