Question

K Calculate number of atoms is each of
the following. (Average atomic mass :
N= 14 u, S = 32 u)
a. 0.4 mole of nitrogen
b. 1.6 g of sulfur
(Ans.: A. 2.4088 x 1023,
B. 3.011 x 1022 atom )
20namotal but :​

Answer 1

Answer :

(a) The number of nitrogen atoms are, $2.4\times 10^{23}$

(b) The number of sulfur atoms are, $3.01\times 10^{22}$

Explanation :

(a) 0.4 mole of nitrogen

As we know that,

1 mole contains $6.022\times 10^{23}$ number of atoms.

As, 1 mole of nitrogen contains $6.022\times 10^{23}$ number of nitrogen atoms

So, 0.4 mole of nitrogen contains $0.4\times (6.022\times 10^{23})=2.4\times 10^{23}$ number of nitrogen atoms

The number of nitrogen atoms are, $2.4\times 10^{23}$

(b) 1.6 g of sulfur

First we have to calculate the moles of sulfur atom.

$\text{Moles of sulfur}=\frac{\text{Mass of sulfur}}{\text{Molar mass of sulfur}}=\frac{1.6g}{32g/mole}=0.05mole$

Now we have to calculate the number of sulfur atoms.

As, 1 mole of sulfur contains $6.022\times 10^{23}$ number of sulfur atoms

So, 0.05 mole of sulfur contains $0.05\times (6.022\times 10^{23})=3.01\times 10^{22}$ number of sulfur atoms

The number of sulfur atoms are, $3.01\times 10^{22}$