Question

The half-life of Zn-71 is 2.4 minutes. If you had 100.Og at the beginning, how

many grams would be left after 4.8 minutes? Show or describe how you solved
this. *

Answer 1

25 g

Step-by-step explanation:

Given data:

Half life of Zn-71 = 2.4 min

Mass of Zn-71 = 100 g

Mass left after 4.8 min = ?

Solution:

First of all we will calculate the number of half lives passed.

Number of half lives = Time elapsed / half life

Number of half lives = 4.8 min/ 2.4 min

Number of half lives = 2

At time zero total mass 100 g

At first half life = 100 g/2 = 50 g

At second half life = 50 g/2 = 25 g

Thus, mass left after 4.8 minuets is 25 gram.