Chemistry: Asample of argon-39 had an original mass of 1578 grams. after 538 years, the sample is 394.5 grams. what is the half-life of argon-39? a. 135 years b. 180 years c. 269 years d. 538 years

Asample of argon-39 had an original mass of 1578

vickyarroyo8888

14.03.2022

C. 269 years

Explanation:

First, we have to find the value of the rate constant (k) through the following expression.

$[Ar]_{t}=[Ar]_{0}.e^{-k.t}$

where,

$[Ar]_{t}$ is the amount of Ar at a certain time t

$[Ar]_{0}$ is the initial amount of Ar

$394.5g=1578g.e^{-k.538y} \\k = 2.577 \times 10^{-3} y^{-1}$

Provided the rate constant, we can find the half-life (t1/2).

t1/2 = ln 2/k = ln 2/2.577 × 10⁻³ y⁻¹ = 269.0 y

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gabelawson6996

24.01.2020

In First compound the longest chain contains 7 C atoms.

In the Second compound the longest chain contains 9 C atoms.

In the Third compound the longest chin contains 7C atoms.

Explanation:

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