75% of a first order reaction is completed in 36 minutes. What is the half life of the reaction?
Correct answer: C. 18 min
- A. 27 min
- B. 24 min
- C. 18 min
- D. 42 min
Explanation
Completion of 75% of reaction = 25% left From 100% conc of reactants to 25% 2 half lives have elapsed. After 1st half life 50% reactants will be left and after 2nd half life 25% will be left.If two half lives take 36 minutes, then half life for this reaction must be 18 minutesSubstituting the value of \(t = 36\) minutes, you can find \(k\). Then, use that \(k\) value to calculate the half-life. After calculating, you will find that the closest answer choice is c. 18 minutes.
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Reaction kinetics relates reaction rate to concentration, temperature, surface area and catalysts. Questions cover rate laws, reaction order, rate constants, activation energy and the activated complex, including how a catalyst lowers the activation energy without changing the overall energy change or equilibrium position.
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