Question 23 of 43beginner🔧 ApplyNumerical3 marks

Find the molecular mass of nitric acid (HNO₃). Atomic mass — H = 1 u; N = 14 u; O = 16 u.

Correct Answer

63 u

Exercise: Pause and Ponder | Q: 21 | (Page 18)
For More Understanding

Explanation

The molecular mass of a substance is the sum of the atomic masses of all the atoms in a molecule of that substance. Following the method shown in the examples for water (H₂O) and carbon dioxide (CO₂), we multiply the atomic mass of each element by the number of its atoms present in the nitric acid molecule and then add the values together.

Solution Steps

  1. Given Atomic masses: H = 1 u; N = 14 u; O = 16 u

  2. Identify number of atoms: In HNO₃, there is 1 hydrogen atom, 1 nitrogen atom, and 3 oxygen atoms.

  3. Calculate individual contributions: (1 u × 1) + (14 u × 1) + (16 u × 3)

  4. Add the values: = 1 u + 14 u + 48 u = 63 u

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