ques no 17 and 19

ques no 17 and 19 = 2.69 x 1019 molecules mple 26 : Calculate number of atoms in 3 mol of NH Number of atoms in one molecule of NH3 = 4 ;olution : Number of atoms in 3 mol of NH3 = 6.02 x 1023 x 3 x 4 = 7.22 x 1024 atoms (ample 27 : An enzyme contains 5.6% Fe, calculate number of Fe atoms present in Ig of enzyme. 'lution : 8. 9. 56 • =5.6x10Qg Mass of Fe = 100 5.0<10 2 x6.02x1023 Number of atoms = 56 = 6.02 x 1020 atoms Try Yourself Calculate the weight of CO having the same number of oxygen atoms as are present in 22 coz What is the molecular mass of substance, each molecule of which contains 4 atoms of carbo and 10 atoms of hydrogen? 19. How many molecules of 02 are present in 1 L air containing 80% volume of 02 at STP? Calculate the volume occupied by (i) 28 u nitrogen gas (ii) 28 g N2 gas at STP.