NTSE Stage 2 SAT 2016 Question Paper

Question : 25 of 100

Marks: +1, -0

Somebody wanted to calculate the number of moles of oxygen atoms comprising of

9.033 ×10^23

number of its atoms. The person further thought to calculate its mass and to find the number of moles of hydrogen atoms required to combine completely with this amount of oxygen to form water.
The number of moles of oxygen atoms, their mass (in grams) and the number of moles of hydrogen atoms are

1.5, 3 and 24 respectively
15, 18 and 3 respectively
0.15, 27, 3 respectively
1.5, 24 and 3 respectively

Validate

Solution:

Given no. of oxygen atoms

=9.033×10^23

(i) moles of oxygen atoms

={9.033×10^{23}}/{6.023×10^23}

(Since number of atoms = number of moles ×Avogadro number)
= 1.499 moles =1.5 moles
(ii) mass of oxygen atoms

=1.5 \moles×16 \gm

=24 grams(since molecular mass of oxygen atom = 16)
(iii)

2\H_2+\O_2→2\H_2\O

2 moles of oxygen atoms requires = 4 gm of

\H_2

1.5 moles of oxygen atoms requires

={1.5×4}/2

= 3 moles of Hydrogen atom

Go to Question:

Prev Question

Next Question