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3 years ago

12

Element X is a radioactive isotope such that every 90 years, its mass decreases by half. Given that the initial mass of a sample

of Element X is 30 grams, how much of the element would remain after 12 years, to the nearest whole number?

1 answer:

steposvetlana [31]3 years ago

4 0

Answer:

approximately 27 grams

Work Shown:

Half life formula

y = A*(0.5)^(x/H)

where,

A = starting amount = 30 grams

H = half life period = 90 years

x = number of years that pass by = 12

y = amount left over after x years

Let's plug the values for x, A and H into the formula to find y

y = A*(0.5)^(x/H)

y = 30*(0.5)^(12/90)

y = 27.3516746567466

y = 27 .... rounding to the nearest whole number

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Step-by-step explanation:

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(a)

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(b)

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(c)

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Step-by-step explanation:

(a)

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we can use property of exponent

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(b)

$-5^{-3}$

we can use property of exponent

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we get

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(c)

$(-5^{-3})^{-1}$

we can use property of exponent

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we get

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(d)

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we get

$(-5^{-3})^{0}=(-5)^{-3\times 0}$

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we can use property

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