The half life of 42K is 12.4 hours. How much of a 750g sample is left after 62.0 hours?

Question

How much of a 750g sample is left after 62.0 hours? Answer with g at the end of it

Answer 1

Amount_after = Amount_before * (1/2)^(t/t_half)

Amount_after = (750 grams) * (1/2)^(62.0 hours/12.4 hours)

Amount_after = 23.4375 grams

750 has 2 significant digits

12.4 and 62.0 have 3 significant digits

So we take the lower of 2 significant digits:

23 grams