Question

Number of moles of substance present in 4.0 g Kr​

Answer 1

Answer:

Number of atoms present in W g of a substance =

M

W

×N

a

.

Here, N

a

represents Avogadro's number. M represents the atomic mass of substance.

Number of atoms in 4 g He=

4

4

×N

a

=N

a

Number of atoms in 46 g of Na=

23

46

N

A

=2N

A

Number of atoms in 0.40 g of Ca=

40

0.4

N

A

=0.01N

A

Number of atoms in 12 g of He=

4

12

N

A

=3N

A

Hence, 12 g of helium has the maximum number of atoms.