Chemical Kinetics and Stability: Chapter 14 Lecture 1

Stability = Important in determining shelf life and expiration date Decomposition = Process of breaking down drug products pH = Level at which thiamine hydrochloride is most stable Buffered vehicle = Prevents degradation of drug products

Temperature = Affects the stability of drug products Humidity = Can impact the stability of thiamine hydrochloride Light = Influences the stability of drug products pH level = Determines the stability of thiamine hydrochloride

Stability = استقرار Decomposition = تحلل pH = درجة الحموضة Buffered vehicle = السيارة المخزنة

<p>Thiamine hydrochloride stable at pH of 2 to 3 = Most stable within a specific pH range Thiamine hydrochloride unstable above pH 6 = Becomes unstable at higher pH levels Select buffered vehicle for preparation = Choose a vehicle that prevents degradation during preparation Stability affected by temperature, humidity, and light = External factors influence the stability of drug products</p> Signup and view all the answers

<p>Molecularity = Number of molecules, atoms, or ions reacting in an elementary process Specific Rate Constant = Constant appearing in the rate law associated with a single-step reaction Half-life = Time required for one-half of the material to disappear Shelf-life = Time required for 10% of the material to disappear</p> Signup and view all the answers

<p>Rates, Order, and Molecularity of Reactions = Classification of reactions into unimolecular, bimolecular, and termolecular Termolecular = A reaction involving three molecules, atoms, or ions Unimolecular = A reaction involving one molecule, atom, or ion Bimolecular = A reaction involving two molecules, atoms, or ions</p> Signup and view all the answers

<p>Chemical Kinetics = Study of rates of chemical processes and reaction mechanisms Stability = Ability of a substance to remain unchanged or maintain a specific form under specified conditions Zero-Order Reactions = Reactions where the loss in color of a dye follows a zero-order rate Kinetic Study = Investigation into the rate of change of concentration over time</p> Signup and view all the answers

<p>Rate = K[Reactant]^a = Representation of the rate law where K is the rate constant and 'a' is the order of reaction dc/dt = K[Reactant] = Expression for the rate, velocity, or speed of a reaction 2NO -&gt; N2O2 (Fast) N2O2 + O2 -&gt; 2NO2 (Slow) = Example revealing real detail mechanism by kinetic study Br H + I 2 -&gt; 2HI 2NO2 -&gt; 2NO + O2 = Example showing molecularity classification</p> Signup and view all the answers

<p>Half-life = Time required for one-half of the material to disappear Shelf-life = Time required for 10% of the material to disappear Life-assumed time = Time at which 10% of the material has decreased to 90% of its original concentration Infinitesimal time interval dt = Very small time period over which concentration changes in a reaction</p> Signup and view all the answers

<p>Elementary Process = Individual step in a reaction mechanism involving a small number of molecules or atoms Order of Reaction = Exponent 'a' in the rate law equation representing how concentration affects the rate of reaction Reaction Mechanism = Sequence of elementary steps that make up an overall chemical reaction Rate Constant = Constant value that relates the rate of a reaction to the concentration of reactants</p> Signup and view all the answers

<p>Concentration Effects = Effects on reaction rates due to changes in reactant concentrations Fundamentals = 'ABC' basics that are foundational to understanding chemical kinetics Kinetic Study Findings = Discoveries related to how rates change over time in chemical reactions Stability in Pharmacy Preparations = 'ABC' basics that are foundational to understanding chemical kinetics</p> Signup and view all the answers

<p>Chemical Kinetics Applications in Pharmacy = Result in production of more-stable drug preparations Real Detail Mechanism by Kinetic Study = Revealed by investigating rates and mechanisms in reactions Molecularity Classification Example = 'Br H + I 2 -&gt; 2HI' showing classification into unimolecular and bimolecular reactions Specific Rate Constant Definition Example = 'Rate = K[Reactant]^a' representing rate law for single-step reactions</p> Signup and view all the answers

<p>Classifying Reactions by Molecularity = 'Unimolecular', 'Bimolecular', and 'Termolecular' classification based on number of reacting species Zero-Order Reactions Study Findings = 'Garrett found that loss in color of dye follows zero-order rate' discovery Half-life Calculation Importance = 'Time required for half material to disappear' crucial for understanding reaction kinetics over time periods Shelf-life Implications on Concentration Changes = 'Time required for 10% material to disappear' helps assess stability based on concentration decrease</p> Signup and view all the answers

<p>Chemical Kinetics Applications in Pharmacy Impact on Drug Preparations = 'More-stable drug preparations' result from utilizing chemical kinetics in pharmacy applications Real Detail Mechanism Discovery Impact on Reaction Understanding = 'Real detail mechanism revealed by kinetic study' enhances comprehension about reaction rates and mechanisms Molecularity Classification Example Impact on Reaction Categorization = 'Br H + I 2 -&gt; 2HI' example aids in categorizing reactions based on number of reacting species Specific Rate Constant Definition Example Impact on Rate Law Understanding = 'Rate = K[Reactant]^a' example clarifies how rate constant and order affect reaction rates</p> Signup and view all the answers