Question

Find the number of nitrogen and hydrogen atoms present in 25.6g of urea
NH 2 CONH 2

Answer 1

Answer:

The number 6.022×1023 is known as Avogadro's number. Thus, the number of moles of urea present in 5.6 g of urea are 0.0933 mol. Thus, 0.0933 mol urea contains 0.3732 mol of hydrogen. Thus, 5.6 g of urea contains 2.247×1023 atoms of hydrogen.

Answer 2

Explanation:

Molecular formula of urea CON

2

H

2

Molar mass of urea = 60gmol

−1

Number of moles of urea = n=

M

W

=

60

5.6

=0.09333mol

Now,

∴ 1 mol urea contains 4 gram atoms of hydrogen(H)

∴ 0.09333mol urea contains==4×0.09333=0.3733 gram atom of H.

Now,

1gm atom of H contains =6.022×10

23

atoms of H.

0.3733gram atom of hydrogen contains = 6.022×10

23

×0.3733=2.248×10

23

Conclusion: Number of H atoms = 2.248×10

23