question_answer 49)

  Verify by calculating that (a) 5 moles of  and 5 moles of  do not have the same mass. (b) 240 g of calcium and 240 g magnesium elements have a mole ratio of 3 : 5.

Answer:

  (a) Molar mass of 1 mole of  has mass = 44 g 5 moles of  have mass = 44 x 5 = 220 g Similarly, molar mass of  1 mole of  has mass = 18 g 5 moles ofhave mass = 18 x 5= 90 g Both the values are not same. So, it is verified. (b) Molar mass of calcium = 40 g  40 g of Ca has number of moles = 1 mol  240 g of Ca has number of moles mol Molar mass of magnesium =24 g  24 g of Mg has number of moles = 1 mol 240 g of Mg has number of moles mol So, it is verified.