Barium – 122 has a half-life of 2 minutes. Suppose you obtain a sample weighing 10.0 g and it takes 10 minutes to set up an experiment. How many grams of Barium – 122 will remain at the point when you begin the experiment

0.3125 g

Explanation:

Given data:

Half life of barium-122 = 2 min

Mass of sample = 10.0 g

Mass of barium remain after 10 min = ?

Solution:

Number of half lives = Time elapsed / half life

Number of half lives = 10 min/ 2 min

Number of half lives = 5

At time zero = 10 g

At 1st half life = 10 g/2 = 5 g

At 2nd half life = 5 g/2 = 2.5 g

At 3rd half life = 2.5 g/2 = 1.25 g

At 4th half life = 1.25 g/2 = 0.625 g

At 5th half life = 0.625 g/2 = 0.3125 g

elements make up everything, and they combine to make compounds.

the answer is c