Physical chemistryLesson 1 of 1 in the course Kinetics

Reaction-Rate Factors: Reactants, Surface Area, and Conditions

5 flashcards · 5 quiz questions · 5 match pairs · 5 fill-in sentences · English

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Summary

The chemical nature or identity of the reactants influences how readily they undergo chemical change. Reactions that seem similar may proceed at very different rates because the substances involved have different chemical properties.

For example, small pieces of sodium react rapidly with substances in air and may be completely changed overnight. Iron exposed to air under comparable conditions is barely affected. The difference is not simply the size of the samples: sodium and iron have different chemical reactivities.

All flashcards

Chemical nature of reactants
The identity and chemical properties of substances that influence how readily they react.
Interface
The boundary where different phases meet and can make contact.
State of subdivision
How finely a solid is divided into particles.
Concentration
The amount of a substance present in a given amount of mixture or space.
Catalyst
A substance that increases the rate of a chemical reaction.

Quiz questions

  1. When calcium and sodium react with water, which comparison of their rates is accurate?Answer: Calcium reacts moderately, while sodium reacts much more rapidly.
  2. Where does a reaction between a solid and a liquid generally occur?Answer: At the boundary where the solid and liquid are in contact.
  3. Why does phosphorus burn more rapidly in pure oxygen than in air?Answer: Pure oxygen provides a higher concentration of oxygen particles.
  4. Why can finely divided iron react with acid faster than large pieces of iron?Answer: The smaller particles expose more surface area to the acid.
  5. What is the general effect of refrigerating food on the reactions responsible for spoilage?Answer: Cooling slows those reactions and delays spoilage.

Based on Chemistry 2e by Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson, PhD (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

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