hce_kmu
114年
物理及化學
第 72 題
A certain drug is metabolized in the human body following second-order kinetics, with the rate law given by: $\text{Rate} = k[\text{D}]^2$
where [D] is the concentration of the drug in mg/L, and $k$ is the rate constant in L$\cdot$mg$^{-1}\cdot$min$^{-1}$. At time t=0, the drug concentration in the bloodstream is 20.0 mg/L. After 30.0 min, the concentration drops to 10.0 mg/L.
How long will it take for the concentration to drop to 5.0 mg/L?
where [D] is the concentration of the drug in mg/L, and $k$ is the rate constant in L$\cdot$mg$^{-1}\cdot$min$^{-1}$. At time t=0, the drug concentration in the bloodstream is 20.0 mg/L. After 30.0 min, the concentration drops to 10.0 mg/L.
How long will it take for the concentration to drop to 5.0 mg/L?
- A 60.0 min
- B 45.0 min
- C 37.5 min
- D 90.0 min
- E 120.0 min
思路引導 VIP
觀察二級反應的半生期公式 $t_{1/2} = \frac{1}{k[A]_0}$，當起始濃度 $[A]_0$ 變為原來的一半時，完成下一次濃度減半所需要的「時間長度」會發生什麼變化？這與一級反應的特性有什麼決定性的不同呢？