Physical Science Chapter 2 Study Guide

Elements, Compounds, and Mixtures

Elements are a class of substances composed of a single kind of atom. Compounds are composed of two or more different elements chemically combined. Mixtures are composed of two or more different elements and/or compounds physically combined. Each element and compound has physical and chemical properties, such as boiling point, density, color, and conductivity, which are independent of the amount of the sample.

Michigan Content Statement Code	Statement
P4.p2A	Distinguish between an element, compound, or mixture based on drawings or formulae.
P4.p2B	Identify a pure substance (element or compound) based on unique chemical and physical properties.
P4.p2C	Separate mixtures based on the differences in physical properties of the individual components.
P4.p2D	Recognize that the properties of a compound differ from those of its individual elements.

Chemical Changes

Chemical changes can occur when two substances, elements, or compounds interact and produce one or more different substances whose physical and chemical properties are different from the interacting substances. When substances undergo chemical change, the number of atoms in the reactants is the same as the number of atoms in the products. This can be shown through simple balancing of chemical equations. Mass is conserved when substances undergo chemical change. The total mass of the interacting substances (reactants) is the same as the total mass of the substances produced (products).

Michigan Content Statement Code	Statement
C5.2B	Distinguish between chemical and physical changes in terms of the properties of the reactants and products.
C5.2C	Draw pictures to distinguish the relationships between atoms in physical and chemical changes.

Endothermic and Exothermic Reactions

Chemical interactions either release energy to the environment (exothermic) or absorb energy from the environment (endothermic).

Michigan Content Statement Code	Statement
C3.4A	Use the terms endothermic and exothermic correctly to describe chemical reactions in the laboratory.
C3.4B	Explain why chemical reactions will either release or absorb energy.

1. P4.p2A: Classify matter as pure or mixture based on pictures or formulae

2. P4.p2B: Identify pure substance as element or compound based on unique chemical and physical properties.

3. P4.p2C: Identify mixture as heterogeneous or homogenous

4. P4.p2C: Identify homogenous substance as solution, alloy, suspension, or colloid

5. C5.2C: Compare and contrast atoms and molecules

6. C5.2B: Define physical properties

7. C5.2B: List and describe 3 physical properties

8. P4.p2C: Name and describe 2 methods of separating a mixture based on the differences in physical properties of the individual components

9. C5.2B, C5.2C: Describe and give an example of a physical change

10. C5.2B: Define chemical properties

11. C5.2B: List and describe 2 chemical properties

12. C5.2B, C5.2C: Describe and give an example of a chemical change

13. C5.2B, C3.4A: Identify 5 indications of a chemical change

14. P4.p2D: Recognize that the properties of a compound differ from those of its individual elements.

15. C3.4B: Explain why chemical reactions will either release or absorb energy.

16. C5.2C: Draw pictures to distinguish the relationships between atoms in physical and chemical changes.