Question

A scientist digs up sample of arctic ice that is 458,000 years old. He takes it to his lab and finds that it contains 1.675 grams of krypton-81.

If the half-life of krypton-81 is 229,000 years, how much krypton-81 was present when the ice first formed?

Use the formula N = N0 .

Answer 1

Correct Answer Is (6.70 grams)

Step-by-step explanation:

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Answer 2

6.70 grams of krypton-81 was present when the ice first formed

Step-by-step explanation:

Let use the below formula to find the amount of sample

`N= N_0((1)/(2))^n`

where

`n = \frac{t}{t_{(1)/(2)}}`

here

t = 458,000 years

`t_{(1)/(2)}` = 229,000

`\frac{t}{t_{(1)/(2)}}` = \
`( 458,000)/(229,000)`

n =
`\frac{t}{t_{(1)/(2)}}` = 2.000

Now substituting the values

`1.675 = N_0((1)/(2))^(2.000)}`

`1.675 = N_0* (0.2500)`

`N_0= (1.675)/(0.2500)`

`N_0=6.70`