Problem solving strategy:

If an element a metal then its molar mass is its atomic mass expressed in grams (gram atomic mass). If an element exists as molecule, its molar mass is its molecular mass expressed in grams (gram molecular mass).

Solution:

a) 1 mole of Na = 23 g

b) Nitrogen occurs as diatomic molecules

$\therefore$ Molecular mass of N₂ = 14 x 2 = 28 amu

Therefore, mass of 1 mole of N₂ = 28 g

c) Molecular mass of C₁₂H₂₂O₁₁= (12 x 12) +(1 x 22) +(16 x 11) = 144 + 22 +176 = 342 amu

Therefore, mass of 1 mole of Sucrose = 342 g