How long will it take for 100 grams of a substance with a half-life of 2 years to decay to a mass of 50 grams?

2 years to decay to a mass of 50g.

Explanation:

given:

100g of substance with a half life of 2 years

to a mass of 50g

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

                          ln 2             0.693

Half life T1/2 =  =  

                              λ                  λ

where  λ = rate constant

The initial amount of 100 grams is decaying to a mass of 50 grams is half of its initial value.

Therefore, it will take 2 years for the decay.