Determine the mass of 10 k Ci sample of `._(11)Na^(24)` Whose half life is 20 hours.

Explanation

`T_((1)/(2))=20` hours. A`=10xx(10)^(3)xx3.7xx10^(10)=3.7xx10^(14)`/second, m=?
`A=lambda N`
`therefore` Number of atoms present in the given sample
`N=(A)/(lambda)=(AxxT_(1//2))/(0.693)=(3.7xx10^(14)xx20xx3600)/(0.693)=3.844xx10^(19)`
Mass of `6.023xx10^(26)` atoms of `Na^(24)` is 24 kg
Mass of `3.844xx10^(19)` atoms, `m=(24xx3.844xx10^(19))/(6.023xx10^(26))=1.53xx10^(-6)kg`