241.

What will be the mass of one  atom in g?

Calculate the mass of:
(i) an atom of sodium
(ii) in a single molecule of water.

 In three moles of ethane (C₂H₆), calculate the following:
Number of moles of carbon atoms.

 In three moles of ethane (C₂H₆), calculate the following:
Number of moles of hydrogen atoms.

 In three moles of ethane (C₂H₆), calculate the following:
Number of molecules of ethane.

How many sulphur atoms are present in each of the following quantities
(i) 4.5 mole of S          
(ii) 6 mole of S₈ ?

How many atoms and molecules of phosphorus are present in 62 g of phosphorus (P₄)?

Calculate the number of molecules present:

(i) in one drop of water having mass of 0.05 g

(ii) in 34.20 gram of cane sugar (C₁₂H₂₂O₁₁).

Calculate the number of atoms of each kind in 5·3 g of Na₂CO₃.

What is the number of molecules of CO₂ present that contains 8g of O₂?