# Chemistry

At a given temperature, a first-order reaction has a rate constant of 3.5 ´ 10–3 s–1. How long will it take for the reaction to be 24% complete?

A chemical reaction that is first-order in X is observed to have a rate constant of 2.20 ´ 10–2 s–1. If the initial concentration of X is 1.0 M, what is the concentration of X after 186 s?

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1. ln(No/N) = kt
No = 100
N = 100-24 = 76
k from the problem
Solve for t in seconds.

#2
Same equation. Different substitutions and solve for N
Post your work if you get stuck.

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2. In[100/76] = 3.5x10^-3 . t
thus T = 7.84x10^-5

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3. 23hr

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