Chemistry Equilibrium and Reaction Rates Quiz

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Questions and Answers

What is the colour of nitrogen dioxide (NO2)?

Colourless

Blue

Green

Brown (correct)

What happens to the solution colour when the reaction mixture is heated?

Remains the same

Becomes more blue (correct)

Becomes more pink

Becomes more colourless

What effect do catalysts have on the rate of reaction?

They increase the activation energy

They change the phase of reactants

They decrease the reaction rate

They increase the rate of reaction without changing equilibrium concentrations (correct)

What is the colour of dinitrogen tetroxide (N2O4)?

Colourless Signup and view all the answers

If the temperature of the reaction mixture is lowered, what colour does the solution become?

More pink Signup and view all the answers

What effect does the presence of inert gas molecules have on the rate of chemical reactions?

They do not change the partial pressures of the reacting gases. Signup and view all the answers

How do catalysts influence the attainability of equilibrium in a chemical reaction?

They provide an alternate pathway with lower activation energy. Signup and view all the answers

What occurs when any disturbance is made to a chemical equilibrium system?

The system will shift to negate the change but not completely nullify it. Signup and view all the answers

What is the effect of temperature changes on the concentration of reactants in equilibrium according to the law of mass action?

The concentration of the favored reactant can never exceed its initial concentration. Signup and view all the answers

Which of the following statements is true about the colors of dinitrogen tetroxide and nitrogen dioxide?

Dinitrogen tetroxide is brown, while nitrogen dioxide is dark orange. Signup and view all the answers

What happens to the partial pressure of a gas when its number of moles per unit volume increases?

It increases according to the ideal gas law. Signup and view all the answers

In the reaction 2𝑁𝑂2(𝑔) + 𝐻2𝑂(𝑙) ⇌ 𝐻𝑁𝑂3(𝑎𝑞) + 𝐻𝑁𝑂2(𝑎𝑞), what is the expected effect of increasing the concentration of 𝑁𝑂2 on the equilibrium position?

The equilibrium will shift to the right. Signup and view all the answers

What is the relationship between total pressure and the number of moles of gas present in a system at constant volume?

Total pressure increases as the number of moles increases. Signup and view all the answers

In the ideal gas reaction where the molar ratio for reactants is 4 and for products is 2, how does an increase in total pressure affect the reaction direction?

The reaction will favor the products. Signup and view all the answers

What is meant by partial pressure in the context of a gas mixture?

It is the hypothetical pressure if only one gas occupies the volume. Signup and view all the answers

What does 'positional disorder' refer to in a chemical system?

The energy configurations or arrangements Signup and view all the answers

What does a standard entropy value (So) represent?

Entropy increase when a substance is heated from 0 K to 298 K Signup and view all the answers

Which of the following statements is true about absolute entropy?

It is always a positive value Signup and view all the answers

What does the Second Law of Thermodynamics state about an isolated system?

Entropy will increase over time, approaching maximum at equilibrium Signup and view all the answers

What is the defining feature of the First Law of Thermodynamics?

Energy movement occurs in accordance with the law of conservation of energy Signup and view all the answers

As temperature approaches zero, what happens to the entropy of a system according to the Third Law of Thermodynamics?

Entropy approaches a minimum Signup and view all the answers

What is the process of combustion?

The oxidation of a substance releasing energy Signup and view all the answers

Which of the following describes the Zeroth Law of Thermodynamics?

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

Which statement is true regarding the process of photosynthesis?

It forms solid glucose molecules. Signup and view all the answers

What is the nature of the change in enthalpy (∆H) during photosynthesis?

It is positive, indicating energy absorption. Signup and view all the answers

Which of the following statements correctly describes a non-spontaneous reaction?

It has ∆G > 0 for all temperatures. Signup and view all the answers

What defines a reaction as exergonic?

It has ∆G < 0. Signup and view all the answers

Which of the following statements is FALSE regarding the relationship between ∆G and reversibility?

∆G > 0 indicates a reversible reaction. Signup and view all the answers

Photosynthesis and respiration are described as which of the following?

Independent processes with different conditions. Signup and view all the answers

What entropy change (∆S) occurs during photosynthesis?

It is negative, indicating decreased disorder. Signup and view all the answers

Which of the following is typically true for reversible reactions?

They have competing entropy and enthalpy drives. Signup and view all the answers

What is overcome during the dissolution of NaCl in water?

Solvent-solvent interactions Signup and view all the answers

Which of the following compounds dissolves endothermically?

KCl Signup and view all the answers

What happens to the entropy of a solid system when it dissolves?

It increases due to free movement of ions. Signup and view all the answers

How do water molecules interrupt ionic lattices during dissolution?

By accumulating attractive ion-dipole forces Signup and view all the answers

What characterizes a saturated solution?

It has reached dynamic equilibrium. Signup and view all the answers

In the dissolution of CaCl2 in water, what type of reaction occurs if some CaCl2 remains undissolved?

Static equilibrium is achieved. Signup and view all the answers

Why do ionic bonds pose challenges during dissolution?

They are extremely strong and stable. Signup and view all the answers

What role do the polar water molecules play in the dissolution process?

They orient towards ions in CaCl2. Signup and view all the answers

Study Notes

IQ1 - Static and Dynamic Equilibrium

Chemical reactions that don't proceed to completion are reversible.
Practical investigations can analyze the reversibility of reactions (e.g., cobalt chloride hydration/dehydration, iron(III) nitrate and potassium thiocyanate, burning magnesium/steel wool).
Dynamic equilibrium occurs in closed systems, where reaction rates are equal in both directions.
Static equilibrium occurs in systems where there are no changes over time.
Non-equilibrium systems are analyzed in terms of entropy and enthalpy (e.g., combustion, photosynthesis).
Collision theory and reaction rate are related to chemical equilibrium.

IQ2 - Factors that Affect Equilibrium

Le Chatelier's principle predicts how changes in temperature, concentration, volume, or pressure affect equilibrium.
Changes in temperature can be investigated with cobalt chloride hydrate reaction, and the interaction between nitrogen dioxide and dinitrogen tetroxide.
Changes in concentration can be analyzed in iron(III) thiocyanate systems or other reactions.
Factors affecting equilibrium can be explained using collision theory.
Activation energy and heat of reaction affect equilibrium position.

IQ3 - Calculating the Equilibrium Constant (Keq)

Equilibrium expressions quantify the relationship between reactants and products in equilibrium.
Keq calculations determine equilibrium concentration.
The equilibrium expression is used for homogeneous reactions.
Quantitatively analyze the effect of temperature on the Keq value
Investigate to determine the Keq of a chemical equilibrium using specific example reactions (e.g. iron(III) thiocyanate equilibrium).

IQ4 - Solution Equilibria

Investigate the dissolution of ionic compounds in water.
Determine solubility rules, predict substance compositions when ionic solutions combine, and derive equilibrium expression using Ksp and calculate solubility.
Processes in ionic compound dissolution relate to chemical equilibrium.

Modelling Dynamic Equilibrium

Practical experiments demonstrate dynamic equilibrium.
Advantages of using certain models to demonstrate dynamic equilibrium,
Disadvantages of using certain models.

Collision Theory and Equilibrium

Collision theory explains chemical reactions based on particle collisions.
Collision theory principles are used to explain reversible reactions.

Other factors Affecting Equilibrium

Investigate the affects of temperature on equilibrium.
Pressure/volume affects on equilibrium.
Catalysts do not affect the equilibrium position, but they do accelerate the rate at which equilibrium is reached.
The direction of reaction shift can be determined through use of Le Chatelier's principle, and the magnitude of this shift can be determined from the values of the equilibrium constants.

Solubility Equilibrium

Understanding factors affecting solubility equilibrium.
Strategies to solve problems involving solubility constants.
Analyze processes involved in ionic compound dissolution in water.

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Description

Test your knowledge on the color changes in nitrogen dioxide and dinitrogen tetroxide, and how catalysts affect reaction rates and equilibrium. This quiz explores key concepts in chemical reactions, including the effects of temperature and inert gases on equilibrium systems.