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3 years ago

In a first-order reaction, the half-life is 139 minutes. What is the rate constant?

Chemistry

1 answer:

Valentin [98]3 years ago

3 0

Answer:

a. 8.31 x 10-5 s-1

Explanation:

The general first-order reaction is:

ln[A] = ln[A]₀ -kt

<em>Where [A] is acutal concentration of reactant, initial concentration is [A]₀, k is rate constant and t is time pass</em>

And the equation of the half-life, t 1/2, is:

$t_{1/2} = \frac{ln 2}{K}$

Has half-life is 139min:

139min * (60s / 1min) = 8340s

$t_{1/2} = \frac{ln 2}{8340s}$

Half-life is 8.31x10⁻⁵ s⁻¹

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3 years ago

At 35.0°c and 3.00 atm pressure, a gas has a volume of 1.40 l. what pressure does the gas have at 0.00°c and a volume of 0.950 l

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The combined gas equation is,

$\frac{P_1V_1}{T_1}=\frac{P_2V_2}{T_2}$

where,

$P_1$ = initial pressure of gas = 3 atm

$P_2$ = final pressure of gas = ?

$V_1$ = initial volume of gas = 1.40 L

$V_2$ = final volume of gas = 0.950 L

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$T_2$ = final temperature of gas = $0^oC=273+0=273K$

Now put all the given values in the above equation, we get the final pressure of gas.

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