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If you are given a 2,900-gram sample of Hydrogen, and hydrogen has a half-life of 2,450 years. How much hydrogen is left after 19,600 years?

User Walchy
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2 Answers

6 votes

Final answer:

To calculate the amount of hydrogen left after 19,600 years, we divide the 19,600-year period by the half-life of hydrogen (2,450 years) to get 8 half-lives. Then, we apply the half-life decay by halving the amount of hydrogen 8 times, which leaves us with approximately 11.33 grams of the original 2,900-gram sample.

Step-by-step explanation:

To calculate the remaining amount of hydrogen after a certain number of years, given its half-life, we use the concept of half-life which is the time taken for half of the sample to decay. Since hydrogen has a half-life of 2,450 years, we can find out how many half-lives have passed in 19,600 years, which is 19,600 divided by 2,450 equals 8 half-lives.

Starting with a 2,900-gram sample of hydrogen, we can now calculate the remaining amount:

  • After 1 half-life: 1,450 grams remain (half of 2,900)
  • After 2 half-lives: 725 grams remain (half of 1,450)
  • After 3 half-lives: 362.5 grams remain
  • ...Continue this process until 8 half-lives have passed...

After the 8th half-life, the remaining amount of hydrogen is 2,900 / (2^8) grams, which equals approximately 11.33 grams of hydrogen.

User AmazingBergkamp
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4 votes

Answer:

11.33g of hydrogen

Step-by-step explanation:

We need to apply the formulae;

Nt/No= (1/2)^t/t1/2

Where;

Nt= mass of hydrogen remaining after a time t (the unknown)

No= mass of hydrogen initially present = 2900g

t= time taken for Nt mass of hydrogen to remain = 19600 years

t1/2= half-life of hydrogen= 2450 years

Substituting values;

Nt/2900= (1/2)^19600/2450

Nt/2900= (1/2)^8

Nt/2900= 1/256

256Nt= 2900

Nt= 2900/256

Nt= 11.33g of hydrogen

Therefore, 11.33g of hydrogen is left after 19600years.

User Victor Sigler
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