Question

Hi !

Calculate the number of oxygen atom in 8.4 g of sodium bicarbonate.


Plzzz...

Answer 1

Hi there !

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Given :

Sodium bicarbonate

It's chemical formula is NaHCO3

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Molecules mass of NaHCO3 is

Na -- 1 × 23 = 23

H  -- 1 × 1     =   1

C  -- 1 × 12   = 12

O -- 3 × 16  = 48

Adding all these ( 23 + 1 + 12 + 48 )

=> NaHCO3 = 84 g

Now, 84 g of NaHCO3 contains 1 mole.

That means ;

84 g of NaHCO3 = 1 mole.

1 g of NaHCO3 = 1 / 84 mole

8.4 g of NaHCO3 = 1 / 84 × 8.4

=> 0.1 mole.

Now,

1 mole of NaHCO3 = 3 mole of oxygen atom.

0.1 mole of NaHCO3 = 3 × 0.1 mole of oxygen atom.

0.1 mole of NaHCO3 = 0.3 mole of oxygen atom.

Therefore,

No. of oxygen atom

=> 0.3 × 6.023 × 10²³

∴ 1.8069 × 10²³    [Ans]

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Thanks for the question !

Answer 2

Hey !! there

For this we first need to find number of mole of NaHCo3,then mole of oxygen

$<b>Now mole=given weight /molecular weight</b>$

◆Here molecular weight of NaHCo3 = 84.007g/mol
which we can also take as 84.g/mol

◆so, mole of NaHCo3 = 8.4/84 = 0.1 mole

$<b>Now, 1 mole of NaHco3 contains = 3 mole of oxygen </b>$

◆hence, mile of oxygen = 3 times of 0.1 mole
I.e, 0.3 mole.

◆Now ,for the number of oxygen atom we just multiply this mole with Avegrado number.

$<b>Avegrado number = 6.022 × 10²³</b>$

◆So, finally no . of oxygen atom in NaHco3

=> 6.022×10²³× 0.3 = 1.8066 × 10²³Ans.

Hope this helped!!!