For a first-order reaction, which expression describes the relationship between the rate constant, k, and the half-life, t1/2?单项选择题

登录即可查看完整答案

我们收录了全球超50000道真实原题与详细解析,现在登录,立即获得答案。

类似问题

The shelf-life for a new product known as “Hyperclear” is reported by the manufacturer to be 28 days. Since the active pharmaceutical ingredient (API) within “Hyperclear” undergoes photochemical degradation, it is stored in light-protective bottles. The API concentration in the “Hyperclear” formulation is 0.092 mol/L.An attentive and concerned pharmacist notices that the expiration date printed on the bottles currently in storage was exactly 4 week(s) ago. The pharmacist needs to dispose of the medication, but they are curious to know how much of the API is still present within the formulation. Whilst the exact value for the rate constant of the API degradation is not available, it is typically reported in the units of M s-1.Determine the remaining concentration of the API at the time of the pharmacist’s discovery. Report your answer in mol/L to 3 decimal places.

Cyanomethane CH3CN, commonly known as acetonitrile, is a toxic volatile liquid, used as solvent to purify steroids and to extract fatty acids from fish oils. Acetonitrile can be synthesised from methyl iso-nitrile by the isomerisation reaction: CH3NC (g) → CH3CN (g) This reaction obeys the first-order rate law: Rate = k [CH3NC], in the presence of Argon. The activation energy for this reaction is 161 kJ mol−1, and the rate constant is 6.6 × 10−4 s−1 at 500. K. Calculate the time (in seconds) required for the concentration of CH3NC to decrease to 95% of its initial value, at 300. K.

Question textFor a first-order reaction, it was found that the initial reactant concentration of 0.66 M reduced to 0.22 M after 3.0 minutes. The rate constant of this reaction is Answer 1 Question 3[input] s-1.

The half-life / shelf-life does not depend on the initial concentration of the reactant. This statement is TRUE for

更多留学生实用工具

加入我们，立即解锁 海量真题 与 独家解析，让复习快人一步！