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Technetium has a half-life of six hours. If you obtain 100g of a pure technetium sample, after 18 hours how much of the pure substance will be remaining?

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Answer: 12.5 grams.

Step-by-step explanation:

You can find the amount of pure substance remaining by using the half-life formula:


Q_(1)=Q((1)/(2))^{(t)/(t2) }

Where t is the amount of time, and t2 is the half life of the substance.

Substituting our values for the variables, we get this equation:


Q_(1) = 100((1)/(2))^3\\\\Q_(1) = 100((1)/(8))\\\\Q_(1) = 12.5

After 18 hours, there will be 12.5 grams of the substance remaining.

User Jeanluca Scaljeri
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