Elements, Compounds, and Mixtures
Elements, Compounds, and Mixtures
Objectives
In this lesson, students will learn that all matter can be classified as either a pure substance or a mixture. They will also learn that both mixtures and pure substances can be broken down into subcategories and that there are techniques chemists use to determine in which category a sample of matter belongs. Students will:
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classify a sample of matter in terms of pure substances and mixtures.
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distinguish between homogenous and heterogeneous mixtures.
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distinguish between solutions, colloids, and suspensions.
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recognize the difference between an element and a compound.
Essential Questions
Vocabulary
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Element: Pure substance consisting of one type of atom.
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Compound: Pure substance consisting of two or more different atoms.
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Mixture: Two or more different substances not chemically combined.
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Colloid: A heterogeneous mixture that exhibits the Tyndall effect.
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Suspension: A heterogeneous mixture that has particles large enough to settle out.
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Solution: A homogenous mixture in which the particles are very small.
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Tyndall effect: The scattering of light in a colloid.
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Homogeneous mixture: A mixture with a uniform composition.
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Heterogeneous mixture: A mixture with a nonuniform composition.
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Element symbol: An abbreviation for an element’s name found on the periodic table.
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Compound formula: Represents the combination of two or more elements in fixed proportions. Subscripts designate the number of atoms of each element.
Duration
90 minutes/2 class periods
Prerequisite Skills
Materials
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pictures of pizza, water, mercury, blood, and cola
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board, markers
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laser pointer
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1000 mL flasks/beakers (2)
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10 to 20 drops of milk
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water
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Mixtures vs. Pure Substances–Teacher (S-8-5-2_Mixtures vs. Pure Substances Teacher.doc)
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Mixtures vs. Pure Substances–Student (S-8-5-2_Mixtures vs. Pure Substances Student.doc)
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Tyndall effect photo: http://www.silvermedicine.org/dark_tyndal_with_h2o2.jpg
Related Unit and Lesson Plans
Related Materials & Resources
The possible inclusion of commercial websites below is not an implied endorsement of their products, which are not free, and are not required for this lesson plan.
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Tyndall effect photo: http://www.silvermedicine.org/dark_tyndal_with_h2o2.jpg