NTSE Stage 2 SAT 2016 Question Paper

Given no. of oxygen atoms =9.033×1023
(i) moles of oxygen atoms =

9.033×1023

6.023×1023

(Since number of atoms = number of moles ×Avogadro number)
= 1.499 moles =1.5 moles
(ii) mass of oxygen atoms
       =1.5‌moles×16‌gm
        =24 grams(since molecular mass of oxygen atom = 16)
(iii) 2H2+O2→2H2O
2 moles of oxygen atoms requires = 4 gm of H2
1.5 moles of oxygen atoms requires
          =

1.5×4

2

          = 3 moles of Hydrogen atom