Chemistry Equilibrium Concepts

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What happens to the reaction rate for the forward reaction when the volume decreases in a gaseous reaction?

It stops completely.

It remains constant.

It increases more than the reverse reaction. (correct)

It decreases significantly.

How does the addition of an inert gas affect the equilibrium position of a reaction?

It does not affect the equilibrium position. (correct)

It causes the reaction to cease.

It shifts the equilibrium to the right.

It shifts the equilibrium to the left.

What is the effect of increasing the total pressure in a reaction involving gases?

It increases the frequency of successful collisions for the products.

It decreases the total number of collisions.

It increases the rate of reaction for both forward and reverse reactions equally.

It increases the collision frequency among reactant particles. (correct)

Which of the following statements regarding catalysts is accurate?

They speed up the rate of both forward and reverse reactions equally. Signup and view all the answers

Why does the reaction rate increase when there are more moles of reactants present?

It leads to a greater frequency of collisions among reactant particles. Signup and view all the answers

What does a reaction with Q < K indicate about the direction of the reaction?

The reaction will proceed to the right. Signup and view all the answers

Which factor is solely responsible for changing the equilibrium constant K?

Temperature changes Signup and view all the answers

In an endothermic reaction, how does an increase in temperature affect K?

K increases. Signup and view all the answers

What does colorimetry analyze?

The absorption of light at a specific wavelength. Signup and view all the answers

Which would cause a system to establish a new equilibrium?

Changing the pressure or volume. Signup and view all the answers

What color does the iron(III) thiocyanate complex appear as?

Blood-red Signup and view all the answers

If Q = K, what can we infer about the system?

The system is at equilibrium. Signup and view all the answers

Which of the following reactions will decrease the value of K if the temperature is increased?

An exothermic reaction. Signup and view all the answers

What type of reaction is photosynthesis considered to be?

Endothermic reaction Signup and view all the answers

What does a positive enthalpy change imply about a process?

The process absorbs heat Signup and view all the answers

Which statement is true regarding the entropy change of photosynthesis?

ΔS is less than zero Signup and view all the answers

What characterizes an irreversible chemical reaction based on ΔG?

ΔG > 0 for all temperatures Signup and view all the answers

What distinguishes photosynthesis from respiration regarding their reaction conditions?

Photosynthesis and respiration occur under vastly different conditions Signup and view all the answers

Which type of reaction is characterized by ΔG < 0?

Exergonic reaction Signup and view all the answers

What is true about competing drives in reversible reactions?

They balance entropy and enthalpy effects Signup and view all the answers

Which reaction is an example of a spontaneous reaction with a negative ΔG?

Respiration Signup and view all the answers

What occurs during the dehydration of cobalt(II) chloride hexahydrate?

It forms cobalt(II) chloride dihydrate and releases water. Signup and view all the answers

What is the primary characteristic of a reversible reaction?

Its products can be converted back into reactants. Signup and view all the answers

Which of the following statements is true regarding the thermodynamic properties of forward and reverse reactions?

If a forward reaction is exothermic, the reverse reaction is endothermic. Signup and view all the answers

What color does anhydrous cobalt(II) chloride appear as?

Sky blue Signup and view all the answers

What happens when cobalt(II) chloride is dissolved in water?

It produces a pink solution of cobalt(II) chloride hexahydrate. Signup and view all the answers

In the context of ionic compounds, what does solubility equilibria help to understand?

It aids in predicting the formation of precipitates based on Ksp values. Signup and view all the answers

What is the outcome of mixing potassium chloride and silver nitrate solutions?

Formation of a silver chloride precipitate. Signup and view all the answers

Which factor can significantly influence the solubility of ionic compounds in water?

The temperature and pressure conditions. Signup and view all the answers

What is required to ensure that the equilibrium position lies heavily to the right in the creation of standard solutions of iron thiocyanate?

The concentration of iron (III) nitrate must be at least 100 times greater. Signup and view all the answers

Which statement accurately describes the relationship between iron thiocyanate and thiocyanate ions during the reaction?

The amount of thiocyanate consumed is virtually equal to the amount of iron thiocyanate produced. Signup and view all the answers

What is the recommended condition for creating standard solutions of iron thiocyanate using potassium thiocyanate?

The concentration of SCN should be significantly greater than that of Fe. Signup and view all the answers

What principle underlies the solubility rule "like dissolves like"?

Solutes dissolve if intermolecular forces between solute and solvent are more favorable. Signup and view all the answers

Which of the following is not relevant when discussing the equilibrium of a reversible reaction like the one used for creating iron thiocyanate?

Limiting reagents. Signup and view all the answers

In the context of creating standard solutions of iron thiocyanate, what does the equilibrium constant Keq provide information about?

The amount of product produced at equilibrium relative to the reactants. Signup and view all the answers

Which ion must be present in large excess when creating standard solutions of iron thiocyanate for effective colorimetry?

Thiocyanate ions. Signup and view all the answers

What does the formation of intermolecular forces between solute and solvent signify when determining solubility?

They must exceed forces between solvent molecules. Signup and view all the answers

What does the term 'positional disorder' refer to in thermodynamics?

The energy configurations of a substance Signup and view all the answers

What is the mathematical expression for the change in entropy during a reaction?

∆S_reaction = ΣS_products - ΣS_reactants Signup and view all the answers

Which statement about absolute entropy is true?

Absolute entropy is theoretically zero for a perfect crystal lattice at 0K. Signup and view all the answers

According to the First Law of Thermodynamics, energy movement into or out of a system is governed by which principle?

Conservation of energy Signup and view all the answers

The Second Law of Thermodynamics states that the entropy of which type of system will increase over time?

An isolated system not at equilibrium Signup and view all the answers

What occurs in the process of combustion?

A substance reacts with oxygen to produce energy Signup and view all the answers

What characterizes the Third Law of Thermodynamics?

Entropy of a system approaches a minimum as temperature approaches zero Signup and view all the answers

The Zeroth Law of Thermodynamics states which of the following?

If two systems are in thermal equilibrium with a third system, they are in thermal equilibrium with each other Signup and view all the answers

Study Notes

IQ1 - Static and Dynamic Equilibrium

Chemical reactions don't always go to completion, some are reversible
Practical investigations analyze the reversibility of chemical reactions (e.g., cobalt(II) chloride, iron(III) nitrate, potassium thiocyanate, burning magnesium, burning steel wool)
Develop models to illustrate static and dynamic equilibrium, contrasting open and closed systems
Analyze non-equilibrium systems in terms of entropy and enthalpy changes (e.g., combustion, photosynthesis)
Explore the relationship between collision theory and reaction rate in relation to chemical equilibrium reactions (ACSCH070, ACSCH094)

IQ2 - Factors that Affect Equilibrium

Investigate how temperature, concentration, volume, and pressure affect equilibrium
Le Chatelier's principle predicts the effects of change in reaction conditions
Examples: heating cobalt(II) chloride hydrate, interaction between nitrogen dioxide and dinitrogen tetroxide, iron(III) thiocyanate
Explore how activation energy and heat of reaction influence the position of equilibrium

IQ3 - Calculating the Equilibrium Constant (Keq)

Deduce equilibrium expressions (Keq) for homogeneous reactions in solution.
Calculate Keq and concentrations of substances in equilibrium systems
Understand how temperature influences Keq
Conduct investigations to find Keq of a chemical reaction (e.g., iron(III) thiocyanate).
Investigate the use of Keq in various chemical reactions (e.g., dissociation of ionic solutions, acid/base dissociation)

IQ4 - Solution Equilibria

Analyze ionic compound solubility in water
Explore the role of intermolecular forces in dissolution
Investigate solubility rules to predict solubility outcomes
Learn how different ions affect the solubility of substances
Understand how solubility and chemical equilibrium are related

Modelling Dynamic Equilibrium

Advantages: -Demonstrates that the rate of forward reaction is proportional to reactants and the reverse reaction is proportional to products. -Models cases where the stoichiometric ratio isn't 1:1. -Show that equilibrium can be re-established if disturbed
Disadvantages:
Doesn't deal with concentration
Water loss can happen
Only works for one reactant/product
Doesn't show reactant to product transformation

Collision Theory

Successful collisions require sufficient energy and correct orientation for reaction.
Explains reversible reaction rates, where the rate of the forward reaction is initially high and decreases as reactants are used up; while the rate of the reverse reaction is initially low, and increase as products are formed.
Explains how a state of dynamic equilibrium where forward and reverse reaction rates are equal

Equilibrium Constant

Quantitative relation between reactant and product concentrations at equilibrium
The ratio of product concentrations to reactant concentrations, raised to the power of their stoichiometric coefficients in a balanced equation
Represents the extent of a reaction in a specific direction

Equilibrium, Temperature, and Catalysts

Temperature affects equilibrium by favoring exothermic or endothermic reactions depending on the temperature change
Catalysts change the rate of both forward and reverse reactions equally, so they don't change the equilibrium position.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the principles of static and dynamic equilibrium in chemical reactions. This quiz covers factors that affect equilibrium, including temperature and concentration, along with practical investigations and models. Engage with concepts like Le Chatelier's principle and reaction rates to deepen your understanding of chemical systems.