Science - 2017-18
PS.2 b, d-f - Classification of Matter
The student will investigate and understand the nature of matter. Key concepts include
b) elements, compounds, mixtures, acids, bases, and salts;
d) physical properties;
e) chemical properties; and
f) characteristics of types of matter based on physical and chemical properties.
Bloom's Levels: Analyze; Understand
- Matter is classified by its chemical and physical properties.
- I can explain why certain substances react with one another and others don't.
- I can identify an unknown substance found on the kitchen counter.
UNDERSTANDING THE STANDARD
- Matter can be classified as elements, compounds, and mixtures. The atoms of any element are alike but are different from atoms of other elements. Compounds consist of two or more elements that are chemically combined in a fixed ratio. Mixtures also consist of two or more substances, but the substances are not chemically combined.
- Compounds can be classified in several ways, including:
- acids, bases, salts
- inorganic and organic copounds.
- Acids make up an important group of compounds that contain hydrogen ions. When acids dissolve in water, hydrogen ions (H+) are released into the resulting solution. A base is a substance that releases hydroxide ions (OH–) into solution. pH is a measure of the hydrogen ion concentration in a solution. The pH scale ranges from 0–14. Solutions with a pH lower than 7 are acidic; solutions with a pH greater than 7 are basic. A pH of 7 is neutral. When an acid reacts with a base, a salt is formed, along with water.
- Matter can be described by its physical properties, which include shape, density, solubility, odor, melting point, boiling point, and color. Some physical properties, such as density, boiling point, and solubility, are characteristic of a specific substance and do not depend on the size of the sample. Characteristic properties can be used to identify unknown substances.
- Equal volumes of different substances usually have different masses.
- Matter can also be described by its chemical properties, which include acidity, basicity, combustibility, and reactivity. A chemical property indicates whether a substance can undergo a chemical change.
In order to meet this standard, it is expected that students will
b) describe how to determine whether a substance is an element, compound, or mixture.
define compounds as inorganic or organic. (All organic compounds contain carbon.)
describe what a salt is and explain how salts form.
d) distinguish between physical properties (i.e., shape, density, solubility, odor, melting point, boiling point, and color) and chemical properties (i.e., acidity, basicity, combustibility, and reactivity).
find the mass and volume of substances and calculate and compare their densities.
e) analyze the pH of a solution and classify it as acidic, basic, or neutral.
determine the identity of an unknown substance by comparing its properties to those of known substances.
f) design an investigation from a testable question related to physical and chemical properties of matter. The investigation may be a complete experimental design or may focus on systematic observation, description, measurement, and/or data collection and analysis. (Students should be able to use the inquiry skills represented in PS.1 and LS.1 to compose a clear hypothesis, create an organized data table, identify variables and constants, record data correctly, construct appropriate graphs, analyze data, and draw reasonable conclusions.)
matter, particle theory of matter, element, compound, mixture, solvent, pH scale, base, salt, acid, solute, inorganic compound, organic compound, density, physical property, chemical property