Qual è l'emivita di un isotopo radioattivo se un campione da 500.0 g decade a 62.5 g in 24.3 ore?

You start with 500.0g.
After the first half-life, you have 250.0g.
After the second, you have 125.0g.
After the third, you have 62.50g.
Therefore, it takes three half-lives to decay to 62.50g.
Therefore, the elapsed time must be triple the length of one half-life.
#24.3/3 = 8.10#, so it is 8.10 hours.