Question

The number of electrons in 8gm of o-2ion is x*10to the power24 then what is x

Answer 1

in one O^-2 ion 10 electrons exist .

mole of O^-2 = given wt/molar wt
= 8/16 = 0.5

so, no of O^-2 ions = mole of O^-2 × Avogadro constant

no of O^-2 ions = 0.5 × 6.023 × 10²³

no of electrons = 10 × no of O^-2 ions
= 10× 0.5 × 6.023 × 10²³
= 3.0115 × 10²⁴

but given, no of electrons = X × 10²⁴
so, X = 3.0115