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iogann1982 [59]
2 years ago
12

A sample contains 16. 75 g of the radioisotope U-236 and 50. 25 g of its daughter isotope, Th-232. How long did it take for deca

y to take place if one half-life of U-236 is 23 million years? 46 million years 69 million years 92 million years 115 million years.
Chemistry
2 answers:
garri49 [273]2 years ago
8 0

The time taken for the isotope to decay is 46 million years.

We'll begin by calculating the number of half-lives that has elapsed. This can be obtained as follow:

  • Original amount (N₀) = 50.25 g
  • Amount remaining (N) = 16.75
  • Number of half-lives (n) =?

2ⁿ = N₀ / N

2ⁿ = N₀ / N

2ⁿ = 50.25 / 16.75

2ⁿ = 3

Take the log of both side

Log 2ⁿ = 3

nLog 2 = Log 3

Divide both side by log 2

n = Log 3 / Log 2

n = 2

Finally, we shall determine the time.

  • Half-life (t½) = 23 million years
  • Number of half-lives (n) = 2
  • Time (t) =?

t = n × t½

t = 2  × 23

t = 46 million years

Learn more about half-life: brainly.com/question/25927447

nekit [7.7K]2 years ago
3 0

Answer:

A.46 Million years

Explanation:

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We can relate the change in heat of a substance with its increasing in temperature using the equation:

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