pH and Color Change

Learning Resource Type

Classroom Resource

Subject Area

Science

Grade(s)

8

Overview

In this lesson, students will see a demonstration of a color change using universal pH indicator. Students will change the concentrations of an acid and a base and use the universal indicator to test the pH of the resulting solutions. Students will see an animation showing that water molecules interact and separate into the H3O+ ion and the OH− ion. Students will see that the pH of a solution is related to the concentration of these ions in water.

Students will be able to explain, on the molecular level, that pH is a measure of the concentration of the H3O+ ions in water and that adding an acid or a base to water affects the concentration of these ions.

Science (2015) Grade(s): 8

SC15.8.5

Observe and analyze characteristic properties of substances (e.g., odor, density, solubility, flammability, melting point, boiling point) before and after the substances combine to determine if a chemical reaction has occurred.

UP:SC15.8.5

Vocabulary

  • Characteristic properties (e.g., odor, density, solubility, flammability, melting point, boiling point)
  • Substances
  • Chemical reaction

Knowledge

Students know:
  • Each pure substance has characteristic physical and chemical properties that can be used to identify it.
  • Characteristic properties of substances may include odor, density, solubility, flammability, melting point, and boiling point.
  • Chemical reactions change characteristic properties of substances.
  • Substances react chemically in characteristic ways.
  • In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.

Skills

Students are able to:
  • Observe characteristic physical and chemical properties of pure substances before and after they interact.
  • Analyze characteristic physical and chemical properties of pure substances before and after they interact.
  • Analyze the properties to identify patterns (i.e., similarities and differences), including the changes in physical and chemical properties of each substance before and after the interaction.
  • Use the analysis to determine whether a chemical reaction has occurred.

Understanding

Students understand that:
  • Observations and analyses can be used to determine whether a chemical reaction has occurred.
  • The change in properties of substances is related to the rearrangement of atoms in the reactants and products in a chemical reaction (e.g., when a reaction has occurred, atoms from the substances present before the interaction must have been rearranged into new configurations, resulting in the properties of new substances).

Scientific and Engineering Practices

Analyzing and Interpreting Data

Crosscutting Concepts

Patterns

CR Resource Type

Lesson/Unit Plan

Resource Provider

American Chemical Society

License Type

Custom
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