Integrated rate laws Knowledge-Based Download PDF

Questions

1. 1.

   For a first-order reaction $\text{A} \rightarrow \text{products}$, the rate constant is $4.62 \times 10^{-2}\text{ s}^{-1}$. If the initial concentration of $\text{A}$ is $0.80\text{ M}$, how much time is required for the concentration of $\text{A}$ to decrease to $0.10\text{ M}$?

   • A) 15 s
   • B) 23 s
   • C) 30 s
   • D) 45 s
2. 2.

   For a reaction of the form $\text{A} \rightarrow \text{products}$, a plot of $1/[\text{A}]$ versus time yields a straight line with a slope of $0.15\text{ M}^{-1}\cdot\text{s}^{-1}$ and a $y$-intercept of $2.0\text{ M}^{-1}$. What is the concentration of $\text{A}$ remaining after $20\text{ s}$?

   • A) $0.20\text{ M}$
   • B) $0.33\text{ M}$
   • C) $0.50\text{ M}$
   • D) $5.0\text{ M}$
3. 3.

   A decomposition reaction A → products follows zero-order kinetics with a rate constant of 0.025 M·s-1. If the initial concentration of A is 1.50 M, what is the concentration of A remaining after 40 s?

   • A) 1.00 M
   • B) 0.25 M
   • C) 0.50 M
   • D) 0.75 M
4. 4.

   For a first-order reaction $\text{A} \rightarrow \text{products}$, the rate constant is $6.93 \times 10^{-3}\text{ s}^{-1}$. What percentage of reactant $\text{A}$ remains after $200\text{ s}$?

   • A) 12.5%
   • B) 25.0%
   • C) 50.0%
   • D) 75.0%
5. 5.

   For a second-order reaction $A \rightarrow \text{products}$, the concentration of $A$ decreases from $0.80\text{ M}$ to $0.40\text{ M}$ in $40\text{ s}$. How much additional time is required for the concentration of $A$ to decrease from $0.40\text{ M}$ to $0.20\text{ M}$?

   • A) 20 s
   • B) 40 s
   • C) 60 s
   • D) 80 s