Verify by calculating the following: (a) Number of molecules in 100 g of NH3 is more than 100 g of N2 [Atomic mass of N = 14 u, H = 1 u] (b) 60 g of carbon and 60 g of magnesium elements have a molar ratio 2 : 1 [Atomic mass of C = 12 u, Mg = 24 u].
The number of moles can be calculated using the formula, No.of moles = Weight of the substance/Molecular weight of the substance N2 100 gms of N2 = (100/2) x 14 moles 100 gms of N2 = 100/28 moles Number of molecules = (100/28) x 6.022 x 10²³ Molar mass of N2 = 2 x molar mass of monoatomic N Molar mass of N2 = 2 x 14.0067 Molar mass of N2 = 28 moles. Number of molecules = (100/28) x 6.022 x 10²³ Number of atoms = 2 x (100/28) x 6.022 x 10²³ Number of atoms = 43.01 x 10²³ NH3 100 gm of NH3 = 100/17 moles Number of molecules = (100/17) x 6.022 x 10²³ molecules Number of atoms in NH3 = 4 x (100/17) x 6.022 x 10²³ Number of atoms in NH3 = 141.69 x 10²³ atoms. Therefore, NH3 has more atoms than N2.
