Calculate the atomicity of mercury molecules from the following data : (a) 10.0 g of mercury combine with 0.8 g of oxygen to form an oxide. (b) 500 mL of mercury vapour at S.T.P. weigh = 4.465g (c) Specific heat of mercury is 0.033.

Calculate the atomicity of mercury molecules from the following data :

1.	Calculate the atomicity of mercury molecules from the following data : (a) 10.0 g of mercury combine with 0.8 g of oxygen to form an oxide. (b) 500 mL of mercury vapour at S.T.P. weigh = 4.465g (c) Specific heat of mercury is 0.033.
Answer» Solution :Calculation of equivalent mass `"0.89 g of oxygen combine with Hg = 10.0 g"` `therefore"8 g of oxygen will combine with Hg "=(10)/(0.8)xx8=100g` `therefore"Equivalent mass of mercury"=100` Calculation of molar mass `"500 ML of mercury VAPOUR at S.T.P. weigh = 4.465 g"` `therefore"22400 mL of mercury vapour at S.T.P. will weigh"=(4.465)/(500)xx22400g=200g` `therefore"Molar mass ofmercury = 200 g mol"^(-1)` Calculation of valency. By Dulong and Petit's law. `"Approx. atomic mass of mercury "=(6.4)/("Sp. Heat")=(6.4)/(0.033)=193.9` `therefore"Valency of mercury"=("Approx. atomic mass")/("Valency")=(193.9)/(100)~~2"(as valency is a whole no.)"` `therefore"Actual atomic mass "="Eq. mass"XX"Valency"=100xx2=200` `"Calculation of atomicity.Atomicity"=("Mol. mass")/("At. mass")=(200)/(200)=1` Thus, mercury molecules are monoatomic.