Question

A radioactive isotope of potassium (K) has a half-life of 20 minutes. If a 255 gram sample of this isotope is allowed to decay for 80 minutes, how many grams of the radioactive isotope will remain? nd the O a. 8.0 0 b. 63.8 O c. 15.9 0 d 319

Answer 1

15.94 g

Step-by-step explanation:

80 mins is 4 half lives ( 20 min each)

255 * 1/2 * 1/2 * 1/2 * 1/2 = 255 * 1/2^4 = 15.94 g