Chemistry Unit 3

Unit Overview – Acids and Bases

The big picture stuff:

In 8th grade, students are introduced to acids and bases, exploring whether a solution is acidic, basic or neutral. While this exploration is continued with significant focus in the California science standards for high school chemistry, this concept is not specifically culled out in the NGSS. However, it is expected that students understand the impact of rising pH in terms of human impacts to the environment. Therefore, the foundational concept of acids and bases is implied as an instructional topic.

Next Generation Science Standards – High School (NGSS-HS):

ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.

Examples: An example of the far-reaching impacts from a human activity is how an increase in atmospheric carbon dioxide results in an increase in ocean acidification, with resulting impacts on sea organism health and marine populations. Through computer simulations and other studies, important discoveries are still being made about how the ocean, the atmosphere, and the biosphere interact and are modified in response to human activities.

Science and Engineering:

• Use a computational representation of phenomena or design solutions to describe and/or support claims and/or explanations.

Crosscutting concepts:

• When investigating or describing a system, the boundaries and initial conditions of the system need to be defined and their inputs and outputs analyzed and described using models.

California Science Standards – Chemistry

5a. Students know the observable properties of acids, bases, and salt solutions.

5b. Students know acids are hydrogen-ion-donating and bases are hydrogen-ion-accepting substances.

5c. Students know strong acids and bases fully dissociate and weak acids and bases partially dissociate.

5d. Students know how to use the pH scale to characterize acid and base solutions.

5f.* Students know how to calculate pH from the hydrogen-ion concentration.

Investigation and Experimentation Standards:

a. Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data.

c. Identify possible reasons for inconsistent results, such as sources of error or uncontrolled conditions.

d. Formulate explanations by using logic and evidence.

j. Recognize the issues of statistical variability and the need for controlled tests.

m. Investigate a science-based societal issue by researching the literature, analyzing data, and communicating the findings. Examples of issues include irradiation of food, cloning of animals by somatic cell nuclear transfer, choice of energy sources, and land and water use decisions in California.