Question

Calculate the number of ATOMS in 8g of oxygen MOLECULES

Answer 1

Answer:

1×6.023×10²³

Explanation:

1 o2 molecule = 2 atoms..

given weight = 8g.

rmm= 16

therefore, no. of moles= weight/ rmm = 8/16 =0 .5moles...

thus,

the no of molecules = moles × 6.023× 10²³ = 0.5× 6.023×10²³

therefore, no. of atoms =2× 0.5 ×6.023×10²³

Answer 2

given mass of Oxygen of molecules (m)

= 8g

molecular mass of oxygen (O2) molecules (M)

= 32g

nunber of moles of Oxygen

= m/M = 8/32 = 1/4

let n be the number of oxygen molecules.

number of moles of Oxygen

= n/N°

$\frac{n}{6.022 \times {10}^{23} } = \frac{1}{4 } \\ n = \frac{6.022 \times {10}^{23} }{4} = \frac{3.011 \times {10}^{23} }{2} \\ n = 1.5055 \times {10}^{23}$

i.e. there are 1.5055 x 10²³ molecules of Oxygen

we know that, in one molecule of oxygen, there are two oxygen atoms.

So,

total number of atoms = 2 x total number of molecules

total number of atoms

= 2n = 2 x 1.5055 x 10²³

= 3.011 x 10²³

Hence, in 8g of Oxygen molecules, there are 3.011 x 10²³ Oxygen atoms.