If you start with
29 g, how much will
be left after 3
half-lives?

3.625g

Explanation:

The definition of a half-life is the time required for any specified property to decrease by half. Given that the question asks for the amount of grams left after 3 half-lives, not the amount of time it takes for 3 half-lives to pass, it can be assumed that it is basically asking what the final value will be when 29g is reduced by half 3 times.

This is shown by the following sequence of equations:

29/2 = 14.5 (after 1 half-life)

14.5/2 = 7.25 (after 2 half-lives)

7.25/2 = 3.625 (after 3 half-lives)

Therefore, the answer is 3.625g.

the correct answer is:

a. formation of precipitation