AP®ChemistryCollege BoardRevision NotesUnit 3: Properties of Substances & MixturesSolutions & MixturesParticulate Representations of Solutions

Particulate Representations of Solutions (College Board AP® Chemistry): Revision Note

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Written by: Martín

Reviewed by: Stewart Hird

Updated on

Particulate Representations of Solutions

  • A solution is a homogeneous mixture of two or more substances

  • The components of a solution are a solute and a solvent

    • The solvent is the component that is in the highest amount

      • Liquids usually act as solvents in solutions

    • The solute is the component that is in the least amount

  • For example, in salt water, salt (sodium chloride) is the solute and water is the solvent

  • Any solution in which water acts as a solvent is called an aqueous solution

  • Concentration is the amount of solute in a given volume of solution; on the AP exam it is usually expressed as molarity (mol of solute per liter of solution)

    • The greater the amount of solute particles in a fixed volume, the greater the concentration

  • A concentrated solution has a large amount of solute particles

  • A dilute solution has a relatively small amount of solute in a given volume of solution

Examiner Tips and Tricks

Solutions are homogeneous mixtures, therefore the molecules of solute and solvent must be evenly spread in the container without forming regions. If individual regions of solute and solvent are formed, it is not a solution

Worked Example

Which diagram represents the most concentrated salt solution?

worked-example-multiple-choice

Answer:

The correct answer is C because:

  • The particles of solute and solvent are evenly spread in the container

  • It has a largest amount of solute particles (salt particles) compared to B which is also a solution

  • A and D are not correct. The particles are forming individual regions of solute and solvent. Therefore, they are heterogeneous mixtures, not solutions

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Martín

Author: Martín

Expertise: Chemistry Content Creator

Martín, a dedicated chemistry teacher and tutor, excels in guiding students through IB, AP, and IGCSE Chemistry. As an IB Chemistry student, he came from hands-on preparation, focusing on practical exam techniques and rigorous practice. While at Universidad San Francisco de Quito, his academic journey sparked a passion for computational and physical chemistry. Martín specializes in chemistry, and he knows that SaveMyExams is the right place if he wants to have a positive impact all around the world.

Stewart Hird

Reviewer: Stewart Hird

Expertise: Chemistry Content Creator

Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.