Answer to Question #165881 in General Chemistry for jane

Question

Phosphorus-32 has a half-life of 14.0 days

days. Starting with 2.00 g of phosphorus- 32, how many grams will remain after 56.0 days ?

Express your answer numerically in grams.

Answer 1

The question tells us we are starting with a 2.00 gram sample of phosphorus-32 and that the half life is 14.0 days. After each half life, 50% of the remaining substance decays. To determine how much is left after 56.0 days, we can explore how much is left after each half life:

• After the first half-life (14.0 days), 1.00 gram of the original sample will remain.
• After the second half-life (28.0 days total), 0.50 gram of the original sample will remain.
• After the third half-life (42.0 days total), 0.25 gram of the original sample will remain.
• After the fourth half-life (56.0 days total), 0.13 gram of the original sample will remain.

Therefore 0.13 gram of the original sample will remain.