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Andru [333]
3 years ago
8

If 250 mg of radioactive element decays to 200mg in 48 hours, find the half-life of the element

Chemistry
1 answer:
Makovka662 [10]3 years ago
7 0
What you can do is use the formula
Nt = N0 [(1 / 2) ^ (t / t(1/2) ) 
<span>where
Nt = current amount of radioactive substances. </span>
<span>N0 = Initial amount of radioactive substances. </span>
<span>t1/2 = half life of radioactive substances. </span>
<span>t = quantity of substances remains after the time t. </span>

Related to what we have, we use the data like this: 
<span>Nt = 200 mg, N0 = 250 mg, , t = 48 hours </span>
Then 
<span>200 = 250 [ (1/2)^ (48 / t(1/2) ) ] </span>
<span>(1/2)^ (48 / t(1/2) ) = 200/250 = 0.8 </span>
<span>48 / t(1/2) = Log ( with the base of 1/2 ) 0.8 = log 0.8 / log 0.5 = 0.32 </span>
<span>t(1/2) = 48 /0.32 = 150 
</span>I hope this can help you a lot
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The vapor pressure of water at 65oC is 187.54 mmHg. What is the vapor pressure of a ethylene glycol (CH2(OH)CH2(OH)) solution ma
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173.83 mmHg is the vapor pressure of a ethylene glycol solution.

Explanation:

Vapor pressure of water at 65 °C=p_o= 187.54 mmHg

Vapor pressure of the solution at 65 °C= p_s

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\frac{p_o-p_s}{p_o}=\frac{n_2}{n_1+n_2}

\frac{187.54 mmHg-p_s}{187.54 mmHg}=\frac{0.3603 mol}{0.3603 mol+4.5672 mol}

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Robert Boyle was the first to determine the relationship between the pressure and volume of a gas.

Boyles states that when the temperature of an ideal gas is kept constant, the pressure of the gas is inversely proportional to the volume occupied by the gas.

Mathematically, Boyles law is given by;

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