Arrange the following in order of decreasing masses: (i) 1023 molecules of CO2 gas (ii) 0.1 g atom of silver (iii) 1 gram of carbon (iv) 0.1 mole of H2SO4 (v) 1023 atoms of calcium. (Given Atomic masses: Ag = 108 u, S = 32 u, N = 14 u, Ca = 40 u)

(i) 1 mole of CO₂ = 44 g = 6.02 x 10²³ molecules

    i.e., 6.02 x 10²³ molecules of CO₂ = 44 g of CO₂

10²³ molecules of CO2 = (44 / 6.02 × 10²³) x 10²³ = 7.31 g

(ii) 1 g atoms of Ag = Gram atomic mass of Ag = 108 g

     ∴ 0.1 g atom of Ag = 0.1 × 108 g = 10.8 g

(iii) 1 g of carbon = 1g

(iv) 1 mole of H₂SO₄ = Gram molecular mass

= 2 x 1+ 32 + 4 x 16 = 98 g

   ∴ 0.1 mole of H₂SO₄ = 0.1 x 98 g = 9.8 g

(v) 1 mole of Ca = 40 g = 6.02 × 10²³ atoms of Ca

  i.e., 6.02 x 10²³ atoms of Ca have mass = 40 g

  ∴ 10²³ atoms of Ca have mass = (40/6.02 × 10²³) x 10²³

= 6.64 g

Thus, masses in the decreasing order are:

0.1 g atom of Ag > 0.1 mole of H₂SO₄ > 10²³ molecules of CO₂ > 10²³ atoms of Ca > 1 g of carbon