Question

Thorium-234 has a half-life of 24 days. How many grams of thorium-234 would remain from 100 g after 72 days? Show your problem-solving technique.

Answer 1

`\underline{ \boxed{12.5 g }}\: of \: (thorium-234 ) \\ \: would \: remain \: from \: \\ 100 g \: after \: 72 \: days`

Step-by-step explanation:

`if \: (Thorium-234) \: has \: a \: (half-life )\: of \: 24 \: days \\ then \: : it \: will \: disintegrate \: into \: (1)/(2) \: of \: 100g \\ but \: after \: 72 \: days \: i.e \: (24 * 3)days \\ it \: will \: reduce \: to\:half \: its \: original \: ( * 3) \\ hence \to \: \\ \frac{100}{ {2}^(3) } = (100)/(8) = (25)/(2) = \underline{ \boxed{12.5g}}`