Question

After 3 half lifes go by, there are 26g of Sodium-24 left. The parent sample of Sodium-24 is

grams.

NUMBERS ONLY FOR THIS ANSWER

Blank 1:

Answer 1

208 grams

Step-by-step explanation:

Half life is the time it takes for a sample to reduce to half it's initial concentration.

In this question, 3 half lives go by. This is given as;

Let original mass be represented by x

First Half life;

Starting mass = X

Remaining mass = X/2

Second Half life;

Starting mass = X/2

Remaining mass = (X/2) / 2 = x/4

Third Half life;

Starting mass = X/4

Remaining mass = (X/4) / 2 = X/8

Since 26g was left, it means;

X/8 = 26

X = 26 * 8 = 208 grams