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3 years ago

PLEASE HELPPPPPPPPP MEEEEEEEEEEE!!!!!

Chemistry

2 answers:

vazorg [7]3 years ago

6 0

Due to the fact that we must find the weight in 300 years, we must find the weight of the element in 3 half-lives. In order to do this, we must divide the original number, 1 kilo, by 1/8 to find the quantity left. 1 kilo = 1000 grams, 1000 g / 1/8 = 125g. This means that the answer should be D.

I hope I've helped! :)

Andrew [12]3 years ago

3 0

Option (d) would be correct

To find the weight of the radioactive element in 300 years, we find its weight in 3 half-lives

Now all you got to do is divide the given weight by 8, it's that easy!

But remember to take the weight in GRAMS

Therefore, you will have 1000/8 = 125 g

(We took 1000 because 1 kg = 1000 g)

And yeah, you can mark H1storyBuff as the 'Brainliest' :)

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Answer:

116 years

Explanation:

To solve this, we will use the half life equation;

A(t) = A_o(½)^(t/t_½)

Where;

A(t) is the amount of strontium left after t years;

A_o is the initial quantity of strontium that will undergo decay;

t_½ is the half-life of strontium

t is the time it will take to decay

We are given;

A(t) = 7.5 g

A_o = 120 g

From online values, half life of strontium-90 is 29 years. Thus, t_½ = 29

Thus;

7.5 = 120 × ½^(t/29)

Divide both sides by 120 to get;

7.5/120 = ½^(t/29)

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In 0.0625 = (t/29) In ½

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(t/29) = -2.772589/(-0.693147)

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4 years ago

Element X had a mass of 300g and a 1/2 life of 10 years. how many grams will remain after 40 years?

kiruha [24]

<h3>Answer:</h3>

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<h3>Explanation:</h3>

Half-life refers to the time taken by a radioactive material to decay by half of the original mass.
In this case, the half-life of element X is 10 years, which means it takes 10 years for a given mass of the element to decay by half of its original mass.
To calculate the amount that remained after decay we use;

Remaining mass = Original mass × (1/2)^n, where n is the number of half-lives

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