Question

How many atoms are present in 8.78 grams O2?

Answer 1

Note the formula

`\boxed{\sf No\:of\:atoms=No\:of\:moles* Avagadro\:no}`

Find no of moles

`\\ \tt{:}\dashrightarrow (8.78g)/(32g/mol)`

`\\ \tt{:}\dashrightarrow 0.27mol[tex]</p><p></p><p>No of atoms</p><p></p><p>[tex]\\ \tt{:}\dashrightarrow 0.27* 6.023* 10^(23)`

`\\ \tt{:}\dashrightarrow 1.6* 10^(23)atoms`

Answer 2

Moles of O_2

• Given mass/Molar mass
• 8.78/32
• 0.27mol

No of atoms

• No of moles×Avagadro no
• 0.27×6.023×10²³
• 1.6×10²³atoms