(i) What is the mass of 1 mole of nitrogen atom? (ii) How many moles of SO_(2) have same mass as 3 moles of oxygen? (iii) How many molecules are present in 1 ml of water?

(i) What is the mass of 1 mole of nitrogen atom? (ii) How many moles

1.	(i) What is the mass of 1 mole of nitrogen atom? (ii) How many moles of SO_(2) have same mass as 3 moles of oxygen? (iii) How many molecules are present in 1 ml of water?
Answer» Solution :(i) 1 `times` gram atomic mass of nitrogen ATOM `""1 times 14=14g` (ii) Mass of 3 moles of oxygen `=3 times 16=48g` `""`, Now, mass of `SO_(2)=32+[2 times 16]` `""=32+32=64g` `""therefore" 64 g of "SO_(2)=` 1 MOLE `"48 g " SO_(2)=(1/64) times 48=0.75` mole (iii) We KNOW that density of water is 1 g/ml Hence, 1 g of water = 1 ml of water Now, We have molecular mass of water `""H_(2)O=(1 times 2)+16=18g` 18 g of water contains `6.022 times 10^(23)` molecules 1 g of water will contains `=(6.023 times 10^(23))/18=0.33 times 10^(23)` molecules So the number of molecules of water in 1 ml `=3.3 times 10^(22)`