The half-life of tc-99 is 6 hours. if starting with 100g of tc-99 what amount would remain after 18 hours? can show your work so i can see how you got the answer

The answer is 12.5 grams of Tc-99.

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You have 3 six-hour cycles in 18h. So it's

First cycle is half of 100 = 50

Second cycle is half of 50 = 25

Third cycle is half of 25 which is 12.5

a rain shadow is a dry region of land on the side that is protected against the prevailing winds of a mountain range. the prevailing winds are the winds that occur most of the time in a particular place of the earth

prevailing winds carry air toward the mountain range. as the air rises up over a mountain range, the air cools, water vapor condenses, and clouds form. on this side of the mountains, called the windward side, precipitation falls in the form of  rain  or snow. this dry air produces a  rain shadow.