Scope, Sequence, and Coordination
A Framework for High School Science Education
Based on the National Science Education Standards
Recognition and Classification of Mixtures
Mixtures, Elements, and Compounds
This grades 5--8 generalization should have been addressed before grade 9. Many students will need to review these concepts.
Pure substances possess a set of characteristic properties, such as melting point, boiling point, density, and chemical reactivity. The properties of mixtures will vary according to the types and quantities of their components.
Mixtures can be separated into purer substances by a variety of processes, such as chromatography, distillation, and crystallization. Mixtures can be classified as either homogeneous (solutions) or heterogeneous. The relative proportions of substances in solutions can be expressed in terms of concentration (percent by mass).
Many chemical processes occur in aqueous solutions. Understanding the nature of these solutions is important for understanding biological and geochemical concepts as well as environmental issues.
Matter, compound, element, mixture, melting point, boiling point, concentration, percent by mass, solutions, homogeneous, heterogeneous, qualitative, quantitative, chromatography, distillation, substance, density, characteristic property, crystallization, solubility, viscosity
Concentration, colligative properties, concentration gradient, diffusion
Mole, molarity, molality
Vapor pressure, boiling point elevation, freezing point depression in solutions
Law of definite proportions, law of multiple proportions
Particulate nature of matter