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Alex777 [14]
3 years ago
12

What percentage of strontium-90 remains in a sample after three half-lives have passed? 12.5% 15% 25% 60%?

Chemistry
2 answers:
AnnyKZ [126]3 years ago
7 0

Answer:

12.5%

Explanation:

The half life of any reaction is the amount of time it takes to consume half of the starting material.

In this case, the original or starting percentage of material is 100%

100% - 50% : First Half Life

50% - 25%   : Second Half life

25% - 12.5% : Third Half life.

After three half lives have passes, the percentage of strontium-90 that remains in a sample is 12.5%

Lyrx [107]3 years ago
4 0

12.5% of strontium-90 would remain in a sample after three half-lives have passed. Half-life automatically means 50% of the original amount would remain.

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The pH of the solution at 25 degree celsius of 1.3 × 10⁻⁶ moles of a sample of Sr(OH)₂ is 10.02.

<h3>How do we calculate pH?</h3>

The pH of any solution gives an idea about the acidic and basic nature of the solution and the equation of pH will be represented as:

pH + pOH = 14

Given that,

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The concentration of Sr(OH)₂ in terms of molarity = 1.3×10⁻⁶/0.025

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Dissociation of Sr(OH)₂ takes place as:

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Given that the base is a strong base and that it entirely dissociates into its ions, the hydroxide ion concentration is 5.2×10¯⁵×2 = 1.04×10¯⁴ M.

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Learn more about pH here:

brainly.com/question/24595796

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2 years ago
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