Question

How much of a sample remains after five half-lives have occurred?

O 1/5 of the original sample
01/25 of the original sample
O 1/32 of the original sample
O 1/64 of the original sample

Answer 1

Every half-life, we end up with half of the material we started with. At the beginning, we have all of the material, which we can represent with the number 1. After one half-life, we have 1 • 1/2 = 1/2 left.

After two: 1/2 • 1/2 = 1/4

Three: 1/4 • 1/2 = 1/8

Four: 1/8 • 1/2 = 1/16

And five: 1/16 • 1/2 = 1/32.

In general, after n half-lives, we’ll have 1/(2^n) of the material left over.

Answer 2

The correct answer is :1 by 32 of the original sample

Step-by-step explanation:

Formula used :

`A=(A_o)/(2^n)`

where,

A = amount of reactant left after n-half lives = ?

`A_o` = Initial amount of the reactant = 100 g

n = number of half lives

If five half-lives have occurred.

`A=(A_o)/(2^5)`

`A=(A_o)/(32)`

Hence, the correct answer is :1 by 32 of the original sample