Table of contents

1. Matter and Measurements4h 31m
2. Atoms and the Periodic Table5h 23m
3. Ionic Compounds2h 18m
4. Molecular Compounds2h 18m
5. Classification & Balancing of Chemical Reactions3h 17m
6. Chemical Reactions & Quantities2h 27m
7. Energy, Rate and Equilibrium3h 46m
8. Gases, Liquids and Solids3h 25m
9. Solutions4h 10m
10. Acids and Bases3h 29m
11. Nuclear Chemistry56m
BONUS: Lab Techniques and Procedures1h 38m
BONUS: Mathematical Operations and Functions47m
12. Introduction to Organic Chemistry1h 34m
13. Alkenes, Alkynes, and Aromatic Compounds2h 12m
14. Compounds with Oxygen or Sulfur1h 6m
15. Aldehydes and Ketones1h 1m
16. Carboxylic Acids and Their Derivatives1h 11m
17. Amines39m
18. Amino Acids and Proteins1h 51m
19. Enzymes1h 37m
20. Carbohydrates1h 41m
21. The Generation of Biochemical Energy2h 8m
22. Carbohydrate Metabolism2h 22m
23. Lipids2h 26m
24. Lipid Metabolism1h 45m
25. Protein and Amino Acid Metabolism1h 37m
26. Nucleic Acids and Protein Synthesis2h 54m

7. Energy, Rate and Equilibrium

Le Chatelier's Principle

GOB Chemistry

7. Energy, Rate and Equilibrium

Le Chatelier's Principle

Previous problemNext problem

1:42 minutes

Problem 50

Textbook Question

Why do catalysts not alter the amounts of reactants and products present at equilibrium?

Verified step by step guidance

Understand the role of a catalyst: A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to proceed. It does this without being consumed in the reaction.

Recognize the principle of equilibrium: At equilibrium, the forward and reverse reaction rates are equal, and the concentrations of reactants and products remain constant. This state is determined by the equilibrium constant (K), which depends only on the temperature and not on the reaction pathway.

Explain how a catalyst affects reaction rates: A catalyst speeds up both the forward and reverse reactions equally by providing an alternative pathway with a lower activation energy. This means the system reaches equilibrium faster, but the relative rates of the forward and reverse reactions at equilibrium remain unchanged.

Clarify why the equilibrium constant (K) is unaffected: Since the catalyst does not change the energy levels of the reactants or products, it does not alter the thermodynamic properties of the reaction, such as the Gibbs free energy. Therefore, the equilibrium constant, which is derived from these properties, remains the same.

Conclude that the amounts of reactants and products at equilibrium are unchanged: Because the equilibrium constant (K) is not affected by the presence of a catalyst, the ratio of reactants to products at equilibrium remains constant, and the catalyst does not alter the equilibrium concentrations.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Chemical Equilibrium

Chemical equilibrium occurs when the rates of the forward and reverse reactions in a chemical process are equal, resulting in constant concentrations of reactants and products. At this state, the system is dynamic, meaning that reactions continue to occur, but there is no net change in the amounts of substances involved.

Catalysts

Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for the reaction to occur, allowing both the forward and reverse reactions to proceed more quickly, but they do not affect the position of the equilibrium.

Le Chatelier's Principle

Le Chatelier's Principle states that if a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the system will adjust to counteract that change and restore a new equilibrium. However, since catalysts do not change the energy levels of reactants or products, they do not shift the equilibrium position.

Watch next

Master Thermodynamics with a bite sized video explanation from Jules

Start learning

Related Videos

Related Practice

Textbook Question

Is the yield of SO₃ at equilibrium favored by a higher or lower pressure? By a higher or lower temperature?

2 SO₂(g) + O₂ ⇌ 2 SO₃(g) ∆H = -47 kcal/mol

1575

views

Textbook Question

What effect do the listed changes have on the position of the equilibrium in the reaction of carbon with hydrogen?

C(s) + 2 H₂(g) ⇌ CH₄(g) ∆H = -18 kcal/mol (-75kJ/mol)

a. Increasing temperature

1231

views

Textbook Question

What effect do the listed changes have on the position of the equilibrium in the reaction of carbon with hydrogen?

C(s) + 2 H₂(g) ⇌ CH₄(g) ∆H = -18 kcal/mol (-75kJ/mol)

b. Increasing pressure by decreasing volume

1125

views

Textbook Question

What effect do the listed changes have on the position of the equilibrium in the reaction of carbon with hydrogen?

C(s) + 2 H₂(g) ⇌ CH₄(g) ∆H = -18 kcal/mol (-75kJ/mol)

c. Allowing CH₄ to escape continuously from the reaction vessel

1282

views

Textbook Question

When the following equilibria are disturbed by increasing the pressure, does the concentration of reaction products increase, decrease, or remain the same?

a. 2 CO₂(g) ⇌ 2 CO(g) + O₂(g)

1350

views

Textbook Question

For the following equilibria, use Le Châtelier's principle to predict the direction of the reaction when the pressure is increased by decreasing the volume of the equilibrium mixture.

a. C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

1618

views

Textbook Question

The reaction CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) has ∆H = -9.8 kcal/mol (-41 kJ/mol). Does the amount of H₂ in an equilibrium mixture increase or decrease when the temperature is decreased?

The reaction H₂(g) + I₂(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease when

c. A catalyst is added?

2370

views

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap