Chemical Kinetics - Analytical 7 Smart PDF

## Chemical Kinetics **هو فرع من الكيمياء الفيزيائية مهتم بفهم سرعة التفاعل الكيميائي** * **A** - معاملات (Reactant) -> **B** - نواتج (Product) **chemical kinetics (time clock)**. is the brauch of Physical chemistery, Concerned with understanding Rate of chemical Reaction speed **Thermodyna...

## Chemical Kinetics **هو فرع من الكيمياء الفيزيائية مهتم بفهم سرعة التفاعل الكيميائي** * **A** - معاملات (Reactant) -> **B** - نواتج (Product) **chemical kinetics (time clock)**. is the brauch of Physical chemistery, Concerned with understanding Rate of chemical Reaction speed **Thermodynamics (time arrow) ** * **A** - مع يتعامل (it deal with) اتجاه (direction in which Process occur) - **B** → But doesnt tell any thing about Rate **اتجاه التفاعل (chemical Reaction")** * بيحدد اتجاه التفاعل (It determines the direction of the reaction) * ولم يتحدد سرعة التفاعل (It does not determine the rate of the reaction) **Kinetics (time clock)** **:: Thermodynamic/is time arrow while chemical Reaction is time clock** **أهمية chemical kinetics في العلم الصيدلي** **importance of chemical kinetics in the pharmaceutical field.** 1- help to understand rate of reaction and factors affect it * بيساعدنا نحدد سرعة التفاعل والعوامل اللي بتأثر على سرعة التفاعل (It helps us determine the rate of reaction and the factors that affect it) 2- help to study drug stability and its shelf life * بيساعدنا ندرس ثبات الدواء وحده صلاحيته (It helps us study drug stability and shelf life) * سرعة تكسير الدواء (rate of drug degradation) "it's Hydrolysis, oxidation and its chemical transformation" * ب) يساعدنا في تحديد مدة صلاحية الدواء (help to determine shelf life of drug) * c) يساعدنا في اختيار طريقة تخزين مناسبة الدواء (help to choice appropriate storage condition of drug) * to minimize its degradation and ensure it's efficacy until reach patient * عشان نقلل تكسيره (to minimize its degradation) * ونضمن كفائته لحد ما يوصل للمريض (and ensure it's efficacy until reach patient) 3- help to study absorption, distribution, metabolism, Excretion of drug "drug bioavailability) * معدل تكسر الدوا في الجسم (rate of drug metabolism in the body) * معدّل امتصاص الدواء (absorption rate of the drug) * معدّل انتشار الدواء في الدم (distribution rate of the drug in the blood) 4- allow to make drug in suitable dosage form. * يساعدنا نحضر الدوا في الشكل الدوائي المناسب (It helps us make the drug in a suitable dosage form) →to ensure the drug reach its target in optimal concentration * لضمان وصول الدواء للمستهدف بالتركيز الأمثل (to ensure the drug reaches its target in optimal concentration) 5- help to optimize manufacturing process of drug * بيساعدنا نظبط عمليه تصنيع الدواء (It helps us optimize the manufacturing process of the drug) * a) help to determine ideal condition for synthesis of API * b) help to maintain quality of drug and minimize waste during synthesis ## معدل سرعة التفاعل **Reaction rate** * **Def:** **Speed of chemical Reaction** * **Def:** is the change in concentration of Reactant or Product with time * **Def:** * هو التغير في تركيز المتفاعلات أو النواتج بمرور الوقت* **conc of Reactants withttime.** **conc of Product ↑ withtime.** **-:unit الوحدة (unit)** * molarity Per Second * " M/S " **Example 1** * **A** * **B** * **t = zero second** * 1 mole A * 0 mole B * **t = 20 second** * 0.54 mole A * 0.46 mole B * **t = 40 second** * 0.30 mole A * 0.70 mole B **Q: Calculate average rate of Apperance of product over 20 second interval.** **Solve** Average Rate of Product. Product - "B" - (معك مع سرعة تكوين النواتج) * = * (التغير في تركيز المتواتج - Change in conc B) * = (التـغير فـي الزمن - Change in time) **[B]f - [8]i * (تركيز النــواتج النهائى - Final concentration of the product "B") (تركيز النــواتج الابتدائى - Initial concentration of the product "B") **t2 - t1** (الزمن النـهائـي - Final time) (الزمن الابتدائى - Initial time) * **= (0.46 - 0) / (20 - 0)** * **= 2.3 x 10^-2 M/s** ## احسب معدل مرية اختفاء المتقابلات **Q: Calculate average rate of disappear of Reactant over 20 second interval ?** **Solve** Average Rate of Reactant. A..= - Change in conc of A - Change in time - **[A]f - [A]i** - **t2 - t1** * **= ( 0.54 - 1 ) / (20 - 0)** * **= 2.3 x 10^-2 M/s** **خلى بالك : الـ Rate لازم قيمته تطلع بالـ Positive * و ديما الـ AA بتطلع بالسالب فلازم نحط سالب في بدايه * القانون عشان الـ Rate يطلع بالموجب** **Q-Rate are always expressed as positive quantities (1)** **Q-the symbol"" mean change. ( )** **Q: the symbol"[]" mean that the conc in molarity. (✓✓✓✓** **Qwe use minus sign in the above equation because of. [A] is always negative , so the negative sign in equation convert the negative of. A (A) into positive ( )** ## بناءاً على الشكل **Q:- from the previous data, calculate average rate of disappearance of reactant over the time intervals from 20 s to 40 s** **Solve** Average Rate of Reactant. A..= - Change in conc of A - Change in time - **[A]f - [A]i** - **t2 - t1** **= ( 0.30 - 0.54 ) / (40 - 20)** **= 1.2 X 10^-2 M/s** ## **saction:** - oxydisulfate ion (S2O82-) reacts with the iodide ion in aqueous solution via the - S2O82-(aq) + 3I- → 2SO4 (aq) + 13- (aq) An aqueous solution containing 0.050 M of S2O82- ion and 0.072 M of I- is prepared, and the progress of the reaction followed by measuring [I-]. The data obtained is given in the table below. | Time (s) | [1-] (M) | |----------|----------| | 0.000| 0.072| | 400.0| 0.057 | | 800.0| 0.046 | | 1200.0 | 0.037 | | 1600.0 | 0.029 | 1) The average rate of disappearance of I- in the initial 400.0 s is - **A) 6.00** - B) 3.8 × 10-5 M/s. - C) 1.4 × 10-4 - D) 2.7 × 104 - E) 3.2 x 10-4 2) The average rate of disappearance of I- between 1200.0 s and 1600.0 s is - A) 1.8 x 10-5 - B) 1.2 x 10-5 - C) 2.0 × 10-5 - D) 5.0 × 104 - **E) 1.6 x 10-4** ## **Dwrite short note on importance of chemical kinetics in pharmaceutical fields** 1- help to undertoned rate of reaction and factores 2- 3- 4- 5- ## **4- allow to make drug in suitable dosage form. * يساعدنا نحضر الدوا في الشكل الدوائي المناسب (It helps us make the drug in a suitable dosage form) →to ensure the drug reach its target in optimal concentration * لضمان وصول الدواء للمستهدف بالتركيز الأمثل (to ensure the drug reaches its target in optimal concentration) 5- help to optimize manufacturing process of drug * بيساعدنا نظبط عمليه تصنيع الدواء (It helps us optimize the manufacturing process of the drug) * a) help to determine ideal condition for synthesis of API * b) help to maintain quality of drug and minimize waste during synthesis** ## **questions** 1 **A scientist conducts an experiment to determine the rate of the following reaction:** - **500(g)+0(g) → 2NO(g)** **If the initial concentration of N. was 0.500 M and the concentration of N₂ was 0.450 M after 0.100 s, what is the rate of the reaction?** - b. 1,00 M/s - c. 5.00 M/s - **d. 10.0 M/s** - **e. 0.250 M/s** 2 **Which of the following statements is correct?** - (a) The rate of reaction decreases with passage of time as the concentration of reactants decreases - (b) The rate of reaction is same at any time during the reaction - (c) The rate of a reaction is independent of temperature change - (d) The rate of a reaction decreases with increase in concentration of reactant (s) 3 **Rate of reaction for reactants is negative because The negative sign indicates decrease in concentrations of reactions with time (T)** 4 **Consider the reaction, A → B. Rate of reaction = + d[B]dt. Which of the following statement(s) defines the positive sign used in the rate of the given reaction?** - a)the concentration of B remain constant with time - **b)increase in the concentration of B with time** - c) decrease in the concentration of B with time - d)the concentration of B is zero 5 **Consider the reaction, A→ B. The rate of reaction = - d[A]at. Which of the following statement(s) define the negative sign used in the rate of the given reaction?** - a)the concentration of A remain constant with time - b)increase in the concentration of A with time - **) decrease in the concentration of A with time** - d)the concentration of A is zero 6 **Chemical kinetics, a branch of physical chemistry, deals with:** - a) heat changes in a reaction - b) physical changes in a reaction - **rates of reactions** - d) structure of molecules 7 **The rate of a chemical reaction:** - a) increases as the reaction proceeds - **b) decreases as the reaction proceeds** - c) may increase or decrease during the reactior - d) remains constant as the reaction proceeds ==End of OCR for page 8==