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Natali [406]
3 years ago
11

Neptunium-240 has a half-life of 1 hour. If you start with a 200-gram sample, how much will remain after 4 hours?

Chemistry
1 answer:
Fynjy0 [20]3 years ago
7 0

Hey there!

A half-life means after a certain amount of time, half of that substance will be gone/changed after that time.

4 hours is 4 half lives because 4 ÷ 1 = 4.

So, the 200g sample will be divided in half 4 times.  

200 ÷ 2 = 100

100 ÷ 2 = 50

50 ÷ 2 = 25

25 ÷ 2 = 12.5

There will he 12.5g of neptunium-240 left after 4 hours.

Hope this helps!

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