Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

15. Chemical Kinetics

Catalyst

General Chemistry

15. Chemical Kinetics

Catalyst

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Multiple Choice

At 300 K, a catalyst lowers the activation barrier from 20 kJ/mol to 10 kJ/mol. Which of the following statements is true regarding the rate constant for the catalyzed reaction compared to the uncatalyzed reaction? (R = 8.314 J mol⁻¹ K⁻¹)

The rate constant for the catalyzed reaction is 10 times larger than the rate constant for the uncatalyzed reaction.

The rate constant for the catalyzed reaction is 2 times larger than the rate constant for the uncatalyzed reaction.

The rate constant for the catalyzed reaction is 100 times larger than the rate constant for the uncatalyzed reaction.

The rate constant for the catalyzed reaction is 55.1 times larger than the rate constant for the uncatalyzed reaction.

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Verified step by step guidance

Identify the Arrhenius equation, which relates the rate constant (k) to the activation energy (Ea): k = A * exp(-Ea / (R * T)), where A is the pre-exponential factor, R is the gas constant, and T is the temperature in Kelvin.

Recognize that the problem involves comparing the rate constants of catalyzed and uncatalyzed reactions. The activation energy for the uncatalyzed reaction is 20 kJ/mol, and for the catalyzed reaction, it is 10 kJ/mol.

Convert the activation energies from kJ/mol to J/mol for consistency with the gas constant R (8.314 J mol⁻¹ K⁻¹). Thus, 20 kJ/mol becomes 20000 J/mol and 10 kJ/mol becomes 10000 J/mol.

Use the Arrhenius equation to express the rate constants for both reactions: k_uncatalyzed = A * exp(-20000 / (8.314 * 300)) and k_catalyzed = A * exp(-10000 / (8.314 * 300)).

Calculate the ratio of the rate constants (k_catalyzed / k_uncatalyzed) to determine how many times larger the catalyzed rate constant is compared to the uncatalyzed one. This involves simplifying the expression: (exp(-10000 / (8.314 * 300))) / (exp(-20000 / (8.314 * 300))).