Question

223Ra decays by alpha emission with a half-life of 11.43 days. For a 1.0g sample of 223Ra, after one half-life, what mass of 223Ra remains? What has happened to the remaining mass?

Answer 1

Step-by-step explanation:

The reaction that shows the alpha decay of
`^(223)_(88)Ra` is:

`^(223)_(88)Ra\rightarrow ^(219)_(86)Rn+^(4)_(2)He`

Half life is the time at which the concentration of the reactant reduced to half. So,

`Mass\ of\ ^(223)_(88)Ra\ remained=\frac {Initial\ concentration}{2}=\frac {1.0\ g}{2}=0.5\ g`

The remaining mass is converted to
`^(219)_(86)Rn`.