Pharmaceutical Analytical Chemistry I

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Questions and Answers

What is the correct term for a reaction that involves an exchange of cations between two compounds in solution?

Metathesis reaction (correct)

Combination reaction

Decomposition reaction

Redox reaction

Which direction represents the formation in the equilibrium reaction A + B ↔ C + D?

Backward reaction

Complete reaction

Equilibrium reaction

Forward reaction (correct)

What occurs to the concentration of reactants as a reaction approaches equilibrium?

There is a constant increase

There is a constant decrease (correct)

It remains equal to products

It fluctuates unpredictably

At equilibrium, the rates of which of the following are equal?

Forward and backward reactions Signup and view all the answers

Which statement about the amount of reactants and products at equilibrium is true?

They remain constant but not necessarily equal Signup and view all the answers

What is defined as the change in concentration of a reactant or product per unit time?

Reaction rate Signup and view all the answers

When a system at equilibrium is disturbed, what is expected to happen?

The equilibrium will shift to restore balance Signup and view all the answers

What term describes a state where concentrations of reactants and products remain constant?

Dynamic equilibrium Signup and view all the answers

What factor does NOT affect the rate of a chemical reaction?

Presence of contaminants Signup and view all the answers

Which statement accurately describes the Law of Mass Action?

The rate of a chemical reaction is directly proportional to the active masses of the reactants. Signup and view all the answers

If the molar concentrations of reactants A and B are both 2 M, what can be inferred about the reaction rate?

The reaction rate will be different than when both concentrations are 1 M. Signup and view all the answers

What is the equilibrium constant represented in the equation?

K represents the ratio of products' concentrations to reactants' concentrations at equilibrium. Signup and view all the answers

What happens to the reaction rate when the concentration of reactants increases?

The reaction rate increases. Signup and view all the answers

Which of the following statements is true regarding covalently bonded molecules in reactions?

They tend to have slower reaction rates compared to ionic reactions. Signup and view all the answers

Which term defines the rate of a reaction in which the concentration of reactants is at 1 M?

Rate constant Signup and view all the answers

What is the likely outcome when physical nature of the medium of reaction changes?

It may either increase or decrease the reaction rate. Signup and view all the answers

What is the relationship between the equilibrium constant Keq and the concentrations of reactants and products at equilibrium?

Keq is calculated as the ratio of products to reactants concentrations. Signup and view all the answers

What happens to the equilibrium when the pressure is increased in a reaction where 4 moles of gas convert to 2 moles of gas?

The equilibrium shifts toward the products. Signup and view all the answers

According to Le Chatelier’s principle, what is expected when the concentration of reactant A is increased?

The equilibrium shifts to the right. Signup and view all the answers

If Keq is greater than 1, what can be inferred about the reaction?

Products predominate at equilibrium. Signup and view all the answers

How does the addition of HCl affect the ionization of acetic acid?

It decreases the ionization of acetic acid. Signup and view all the answers

Which statement about the effect of catalysts on Keq is true?

Catalysts have no effect on the equilibrium constant Keq. Signup and view all the answers

What is the effect of adding AgNO3 to a saturated solution of AgCl?

It decreases the solubility of AgCl. Signup and view all the answers

How does Le Chatelier's Principle describe the response of a system at equilibrium when a stress is applied?

The system shifts in a direction to decrease stress. Signup and view all the answers

In an exothermic reaction, what happens when energy is added?

The equilibrium shifts to the left. Signup and view all the answers

Which of the following scenarios would not result in a shift of equilibrium?

Increasing the pressure in a reaction with equal moles of gas on both sides. Signup and view all the answers

What effect does the common ion effect have on weak acids or bases?

It suppresses their ionization. Signup and view all the answers

Which factor does not influence the equilibrium position of a reaction?

Presence of catalysts. Signup and view all the answers

If the concentration of a product is increased, what is the expected effect on the equilibrium position?

The equilibrium shifts to the left. Signup and view all the answers

For a reaction involving gases, how does an increase in pressure affect the equilibrium position?

It favors the side with fewer moles of gas. Signup and view all the answers

Which reaction demonstrates no change in total moles of gas during pressure alteration?

H2 + I2 ⇌ 2 HI Signup and view all the answers

What is true about the equilibrium constant's dependence on temperature?

Keq can vary with temperature and pressure. Signup and view all the answers

Study Notes

Introduction to General Inorganic Chemistry

Pharmaceutical Analytical Chemistry I (PC 111), Level I, Pharm D Clinical
Lecture 6
Presented by Dr. Galal Magdy, PhD

Metathesis Reactions

Metathesis (double replacement) reactions involve two compounds in solution, exchanging cations with anions
Example: AgNO₃(aq) + NaCl(aq) → AgCl(s) + NaNO₃(aq)

Chemical Equilibrium

A chemical reaction has a forward and a backward reaction
Products of a reaction interact to form reactants
This occurs simultaneously in both directions
Reaction rates change as the reaction progresses
Equilibrium occurs when forward reaction rate equals reverse reaction rate
At equilibrium, concentrations of reactants and products remain constant

Dynamic Equilibrium

A state of equilibrium where the forward and backward reaction rates are equal, yet there is continuous exchange of products and reactants
Concentrations of reactants and products are constant

Reaction Rate

Reaction rate = change in reactant/product concentration per unit time
Some reactions are fast, others are slow
Generally, ion-based reactions are rapid
Covalent reactions are often slower
Examples:
- Rapid: Ag⁺(aq) + Cl⁻(aq) → AgCl(s)
- Slow: Iron to iron oxide (rust)

Factors Affecting Reaction Rate

Nature of reactants
Reactant concentration
Pressure (gaseous systems)
Temperature
Catalysts
Physical nature of reaction medium

Effect of Concentration on Reaction Rate

Collisions between ions or molecules lead to product formation
Increasing the number of reactant moles increases collision chances, thus increasing reaction rate
The law describing concentration's effect on reaction rate is the Law of Mass Action (Law of Chemical Equilibrium)
Reaction rate is directly proportional to the active masses (molar concentrations) of reacting substances

Rate Constant

The rate constant (k) is the proportionality constant relating the rate of a reaction to the concentrations of reactants
If reactant concentrations are 1 M, the rate equals the rate constant
Rate = k[A]^m[B]ⁿ

Equilibrium Constant (K_eq)

The equilibrium constant (K_eq) is the ratio of the rate constant for the forward reaction (k₁) to the rate constant for the reverse reaction (k₂) at equilibrium
The ratio is equal to the molar concentration of products raised to their respective stoichiometric coefficients divided by a similar term for reactants K_eq = ([C]^c[D]^d)/([A]^a[B]^b)

Factors Affecting K_eq

K_eq is not affected by catalysts, concentration changes, or equilibrium position changes
K_eq is affected only by temperature and pressure and depends on reactant nature

Le Chatelier's Principle

When a stress is applied to a system in equilibrium, the equilibrium shifts in a direction that neutralizes the stress
Factors affecting the reaction equilibrium: temperature, pressure, and concentration

Temperature

Exothermic reaction: Adding energy shifts equilibrium to the left
Endothermic reaction: Adding energy shifts equilibrium to the right

Pressure

Pressure affects equilibrium only if one or more reactants or products are gases
Increasing pressure shifts equilibrium towards the side with fewer moles of gas

Concentration

Increasing reactant concentration shifts equilibrium to the right
Increasing product concentration shifts equilibrium to the left

Common Ion Effect

Adding a strong electrolyte with a common ion to a solution of a weak electrolyte decreases the concentration of the common ion
It suppresses the ionization of weak acids or bases

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Description

This quiz covers key concepts from Lecture 6 of Pharmaceutical Analytical Chemistry I. It focuses on metathesis reactions, chemical equilibrium, and dynamic equilibrium, providing examples and explanations to enhance your understanding. Test your knowledge on these fundamental topics essential for a Clinical Pharm D program.

Pharmaceutical Analytical Chemistry I - Lecture 6

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