# If a 12.0-g sample of radon-222 decays so that after 19 days only 0.375 g remains, what is the half-life of radon-222?

##### 1 Answer

Jun 26, 2017

#### Answer:

The half life is

#### Explanation:

The original mass is

After

The ratio of

That is

The half life is

So,

We can perform the calculation