Question

After two half-lives, how much of the original material has decayed? 25 percent 50 percent 75 percent 100 percent

Answer 1

Answer:

75% of the material has decayed.

Explanation:

Hello,

We can start this problem by solving the first half-life assuming the arbitrary condition stating that the initial concentration has a value of 100M, thus, for the first half-life, the concentration dwindles to 50M. Afterwards, the second half-life yields a concentration of 25M, meaning that the 75% of the material has decayed up to the second half-life, of course, the half of the result from the first half-life.

Best regards.

Answer 2

Answer:

After two half lives the sample will remain 25%.

Explanation:

Given data:

Number of half lives given = 2

Mass remain after two half lives = ?

Solution:

Consider that original sample is 100 g.

At time zero = 100 g

After first half life = 100 /2 = 50 g

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

So after two half lives the sample will remain 25%.