5.25 g
Step-by-step explanation:
The half-life of a radioactive substance is the amount of time it takes for half the mass of the substance to decay.
In this question no calculations are required to get half-life. This is because it is given that it took 3 years for the 14g to halve to 7g.
To find amount of the substance after a further 4 years, we’ll use the formula;
Final amount = initial amount / 2ⁿ
Where n = elapse time / half-life
We begin by finding n;
n = 4 years / 3 years
= 4/3
Final amount;
= initial amount / 2ⁿ
= 7 / 2 ^ (4/3)
= 5.25 g
Learn More:
For more on half-lives calculations check out;
brainly.in/question/3080737
https://brainly.com/question/1831303
https://brainly.com/question/2674699
