Question

Calculate the number of oxygen atoms in 0.20 mole of Na2CO3.10H2O

Answer 1

1 mole of Na2CO3.10H2O contains 13 mole oxygen.

0.20 mole will contain 0.20*13=2.6

Hence, no. of oxygen atom = 2.6*NA

=15.6598*10^23

Answer 2

Number of oxygen atoms is $1.567 \times 10^{24}$  

Explanation:

For $Na_2CO_3. 10H_2O$, we know that 1 mole of $Na_2CO_3. 10H_2O$ contains 13 moles of oxygen.

So, for “0.2 moles” of $Na_2CO_3. 10H_2O$, we will have 13 ×0.2= 2.6 moles of oxygen.

We also know that 1 mole of anything is $6.023 \times 10^{23}$ which is Avogadro’s number that states “the number of constituent elements in 1mole of any substance”.

So the number of “oxygen atoms” in 1 mole of $Na_2CO_3. 10H_2O$ $= 6.023 \times 10^{23}$

The number of oxygen atoms in 2.6 moles of $Na_2CO_3. 10H_2O$ $= 2.6 \times 6.023 \times 10^{23}$

$=15.567 \times 10^{23}$

$Number \ of \ oxygen \ atoms = 1.567 \times 10^{24}$