Element X is a radioactive isotope such that every 75 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 920 grams, how much of the element would remain after 3 years, to the nearest whole number?Answer:
Q. Element X is a radioactive isotope such that every 75 years, its mass decreases by half. Given that the initial mass of a sample of Element X is 920 grams, how much of the element would remain after 3 years, to the nearest whole number?Answer:
Determine half-life of Element X: Determine the half-life of Element X. The half-life of Element X is given as 75 years. This means that every 75 years, the mass of Element X is reduced by half.
Calculate number of half-lives: Calculate the number of half-lives that occur in 3 years.Since the half-life is 75 years, we need to find out how many 75-year periods fit into 3 years. This is done by dividing 3 by 75.Number of half-lives = 3 years / 75 years = 0.04 half-lives (approximately).
Use exponential decay formula: Use the exponential decay formula to find the remaining mass.The formula for exponential decay is:Final mass = Initial mass ×(1/2)Number of half-livesWe will use the number of half-lives calculated in Step 2 to find the remaining mass after 3 years.
Plug values into formula: Plug the values into the exponential decay formula.Final mass = 920 grams ×(21)0.04To calculate this, we need to evaluate (21)0.04.
Calculate (21)0.04: Calculate (21)0.04. Using a calculator, we find that (21)0.04 is approximately 0.971.
Multiply initial mass: Multiply the initial mass by the decay factor to find the final mass.Final mass = 920 grams ×0.971Final mass ≈893.32 grams
Round final mass: Round the final mass to the nearest whole number.The final mass of Element X after 3 years, rounded to the nearest whole number, is approximately 893 grams.
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