Friday, 5 January 2018

What is the mass of Question 7 from Chapter 3. Atoms And Molecules

(a) 1 mole of nitrogen atoms?
(b) 4 moles of aluminium atoms (Atomic mass of aluminium= 27)?
(c) 10 moles of sodium sulphite (Na2SO3)?

Answer :The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams. The atomic mass of an element gives us the mass of one atom of that element in atomic mass units (u). To get the mass of 1 mole of atom of that element, that is, molar mass, we have to take the same numerical value but change the units from 'u' to 'g'.
Molar mass of atoms is also known as gram atomic mass. For example, atomic mass of hydrogen=1u. So, gram atomic mass of
hydrogen = 1 g.

(a) The mass of 1 mole of Nitrogen atoms = 14 g.

(b) The mass of 4 moles of Aluminium atoms is (4 × 27) g = 108 g

(c) The mass of 10 moles of Sodium Sulphite (Na2SO3) =10 × [2 × 23 + 32 + 3 × 16] g = 10 × 126 g = 1260 g

This is an answered question from Chapter 3. Atoms And Molecules of CBSE Class 9th Science

Check for Complete Exercise Solution for Chapter 3. Atoms And Molecules | CBSE Class 9th Science

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