CourseCourseConceptConceptDocsDocuments

IB Chemistry HL 2.2.3 Factors Affecting Rate Questions

Use real HL experiments and curves to predict and explain how reaction conditions change rate while controlling other variables.

Syllabus
First assessment 2025
Course
Chemistry HL
Level
HL

Exam points

  • Predict how concentration, pressure, temperature, surface area or a catalyst changes reaction rate and the product-versus-time curve.
  • Explain pressure, concentration and surface-area effects through collision frequency, and temperature effects through kinetic energy and the fraction above activation energy.
  • Distinguish a catalyst effect on rate from a change in the final amount of product or equilibrium position, keeping other conditions controlled.

Learn this topic

Study 2.2.3—Factors affecting rate conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB Chemistry HL 2.2.3 Factors Affecting Rate Questions question 1

[Maximum number: 2]

When nitrogen gas and hydrogen gas are allowed to react in a closed container the following equilibrium is established.

N2( g)+3H2( g)⇌2NH3( g)ΔH=−92.6 kJ\mathrm{N}_{2}(\mathrm{~g})+3 \mathrm{H}_{2}(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{~g}) \quad \Delta H=-92.6 \mathrm{~kJ}

Typical conditions used in the Haber process are 500∘C500^{\circ} \mathrm{C} and 200 atm , resulting in approximately 15 % yield of ammonia.

Explain why a temperature lower than 500∘C500^{\circ} \mathrm{C} is not used.

All question bank results loaded