Hydrogen-3 has half life of 12.32 years. A sample of H-3 weighing 3.02 grams is left for 15.0 what will the final weight of H-3 sample be

1.3 grams

Explanation:

Given dа ta:

Half life of H-3 = 12.32 years

Amount left for 15.0 years = 3.02 g

Final amount = ?

Solution:

First all we will calculate the decay constant.

t₁/₂ = ln² / k

t₁/₂ = 12.32 years

12.32 y = ln² / k

k = ln²/12.32 y

k = 0.05626 y⁻¹

Now we will find the original amount:

ln (A°/A) = Kt

ln (3.02 g / A) = 0.05626 y⁻¹ * 15.0 y

ln (3.02 g / A) = 0.8439

3.02 g / A = e⁰°⁸⁴³⁹

3.02 g / A = 2.33

A = 3.02 g / 2.33

A = 1.3 g

The final mass of sample is 1.3 g.