The half-life of the reaction is 50 minutes
Data;
- Time = 43 minutes
- Type of reaction = first order
- Amount of Completion = 45%
<h3>Reaction Constant</h3>
Let the initial concentration of the reaction be X
The reactant left = (1 - 0.45) X
= 0.55 X
= X
For a first order reaction

<h3>Half Life </h3>
The half-life of a reaction is said to be the time required for the initial amount of the reactant to reach half it's original size.

Substitute the values

The half-life of the reaction is 50 minutes
Learn more on half-life of a first order reaction here;
brainly.com/question/14936355
Answer:The mass numbr is 22
Explanation:
Mass number=number of protons+ number of neutrons....which is 10+12=22
Answer is (3) protons and neutrons.
(P.S. The outer part contains the electrons)
Your answer is B.
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