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jeka94
3 years ago
10

Calcium-45 has a half-life of 162.7 days. If four half-lives have elapsed, how much time has passed?

Chemistry
2 answers:
vovikov84 [41]3 years ago
7 0
Half-life<span> is the time required for a quantity to reduce to half its initial value. </span><span>If four half-lives have elapsed for calcium-45, then it would be 4x162.7 = 650.8 days have passed. Hope this answers the question. Have a nice day. Feel free to ask more questions.</span>
Len [333]3 years ago
6 0

Answer:

1.78 years

Explanation:

First half life is the time at which the concentration of the reactant reduced to half.

Second half reaction is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/4.

Third half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/8.

Fourth half life is the time at which the remaining concentration reduced to half or the initial concentration reduced to 1/16.

There are four half lives. So, time has passed = 4*162.7 days = 650.8 days = 1.78 years

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4 0
3 years ago
What is the difference in concentration between a pH of 7 and 12?
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Answer:

The pH of a solution is simply a measure of the concentration of hydrogen ions,  

H

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H

3

O

+

.

More specifically, the pH of the solution is calculated using the negative log base  

10

of the concentration of the hydronium cations.

∣

∣

∣

∣

¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯

a

a

pH

=

−

log

(

[

H

3

O

+

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)

a

a

∣

∣

−−−−−−−−−−−−−−−−−−−−−−−−  

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10

because the concentration of hydronium cations is usually significantly smaller than  

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Explanation:

4 0
3 years ago
Read 2 more answers
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