Question

plz answer 1 part.....

Answer 1

a)  3.012 x 10^23 molecules
Molecular mass of water(H2O)= (1×2)+16=18g/mol

1 mole of water=18g of water contains=6.022×1023 molecules of water

then 9g of water will have= (6.022×1023/18)×9 = 3.011×1023 molecules


B)6.023x10^23 molecules 
The molar mass of nitrogen is 14 g while that of hydrogen is 1g. The chemical formula for ammonia is NH3, so the molar mass of ammonia will be 

= molar mass of nitrogen + 3 X (molar mass of hydrogen)

= 14 + 3 X (1) = 17 g

Thus the molar mass of ammonia is 17 g. This means that there are 6.023 X 1023 molecules of ammonia present in 17 g of ammonia. That is 

 17 g of NH3 = 6.023 X 1023 molecules of ammonia


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