# A chemical substance has a half life of 5 years. A chemist currently has 2000 grams of the substance. If the substance remains untouched, after 25 years, how much of the substance will be left?

##### 1 Answer

Apr 29, 2017

after 25 years there would be

#### Explanation:

Half life refers to the time it takes or half of the substance to decay.

If the half life is 5 years and we begin with 2000 grams, we can create a data list of the decay.

0 years = 2000 grams

5 years = 1000 grams

10 years = 500 grams

15 years = 250 grams

20 years = 125 grams

25 years = 62.5 grams

You can also use the formula