Question

Cesium-137, used in cancer treatment, has a half- life of 30 years. are here 1974 used in cancer treatment, has a half-

Answer 1

In an alpha-emission nuclear reaction, a loss of 4 units in atomic mass and a loss of 2 units in atomic number will occur.

In an beta-emission nuclear reaction, there is no change in atomic mass. A increase of 1 unit in atomic number will occur.

kinetic equation of a nuclear decay reaction is :

ln ( [A0] / [A] ) = K.t

K : Decay constant

Where [A0] is the initial concentration

[A] is the concentration left at time t

Half life( T1/2) equation : T1/2 = (ln 2) / K

Answers are shown in figures:

137 1370 Part A : so Part B : ln (A) = kt and Time = ln 2 Given data: 4 = 30 years - [A] = 24 g t = 120 years Substituting ; K= (102)/60 years) = 0.0231 year' and; ln 249 - (0.0 231 year') (120 years) solving this, [4] = 105 g Partc: ln [A) - Kit Given data: [A] = 38g [A] = 190 we calculated value of k in previous part. K=0.0231 year Substituting in equation; In ( 38 ) = (0.0931) + Solving for t, we get t = 30 years LAJ
    
Beta decas of Sulfur-35 Alpha decay of Actiniums-226 222 226 89 "Ac

→ 210 Ra-210 (x-decay) geRa Rnt He Co-GO (2-decay) Co - Cot/ - 60