Half-life of things

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I’ve been reading about HL, but I still don’t get why would you use it. So, if half life of coffee is 5h, how that info is relevant when we know that full life is 10 (roughly)? On top of that, how do you get the half-life of a material other than waiting to be completely ‘dead’ and say, ok full life is X, the half life is X/2.
Also, let’s take uranium which in Earth’s crust has a half-life of almost 4.5 billion years.. how did we get this number?

Thank you!

In: Chemistry

16 Answers

Anonymous 0 Comments

There is no full-life concept. Half-life is just the time it takes for half the material to decay. So if 1lb of matter has a half-life of an hour, in one hour there would only be half a pound left. Next hour there only be half of that left so a quarter pound. Your body has noticeable reactions to caffeine at and above 30mg. If the half-life of caffeine in your system is 6hours, and you took 100mg. It would take about 12hours(100mg hour0, 50mg hour6, 25mg hour12) for your body to stop being affected by it. As far as discovering half life you just monitor the average rate of decay and do the math to see how much time it takes for half of it to be gone.

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