Chemical Changes: reacting an acid and base
Initial Publication Date: September 22, 2008
Summary
In this chemistry lab, students will investigate chemical changes that occur when acids and bases react. It is meant to introduce the concepts of chemical changes, gases have mass, conservation of mass, and balancing equations. Students will make qualitative observations and quantitative measurements.
CollapseLearning Goals
1. Students will describe the characteristics of a chemical changes
2. Students will accurately collect mass measurements of reactants and products
3. Students will analyze the data to determine is mass is lost
4. Students will explain where the mass has gone
Key concepts:
Conservation of mass
Qualitative
Quantitative
Chemical changes
2. Students will accurately collect mass measurements of reactants and products
3. Students will analyze the data to determine is mass is lost
4. Students will explain where the mass has gone
Key concepts:
Conservation of mass
Qualitative
Quantitative
Chemical changes
Context for Use
This is a lab that will take place in one period. It is taught in 8th grade as part of a small chemistry unit. Access to an electronic balance is necessary. Students should know proper safety measure for handling glassware and chemicals.
Description and Teaching Materials
Students will mass out 0.15 grams of sodium carbonate and add 1 mL drop by drop of .5 M HCl until all of the solid is dissolved and bubbling stops. Students will observe for signs of chemical changes. After the reaction is done they will determine the mass of the products and compare it to the mass of reactants. They should see a loss of mass due to carbon dioxide loss. We will discuss the law of conservation of mass and how even gases have mass.
This is adapted from the USAFA Department of Chemistry: Mini-Lab Pass the Salt
This is adapted from the USAFA Department of Chemistry: Mini-Lab Pass the Salt
Teaching Notes and Tips
Safety: Goggle are mandatory. This is exothermic and involves acid so extreme care must me used when adding acid to base. Review safety with students
Students need to measure the mass of the HCl as well as the sodium carbonate.
I have used alkaseltzer in the past but both the acid and base are bound together in the tablet. Although much safer it doesn't give the impression of a chemical reaction.
Students need to measure the mass of the HCl as well as the sodium carbonate.
I have used alkaseltzer in the past but both the acid and base are bound together in the tablet. Although much safer it doesn't give the impression of a chemical reaction.
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Assessment
Students keep a science notebook in class. This lab will be checked for observations, measurements, data tables, and reflections.
Standards
Grade 6 II Physical Science
Substrand A. Structure of Matter
- Student will know the mass of a substance remains constant whether it is together, in parts or in a different state.
Substrand B. Chemical Reactions
- Student will define chemical and physical changes
- Students will observe that substances react chemically with other substances to form new substances with different characteristic properties.
Substrand A. Structure of Matter
- Student will know the mass of a substance remains constant whether it is together, in parts or in a different state.
Substrand B. Chemical Reactions
- Student will define chemical and physical changes
- Students will observe that substances react chemically with other substances to form new substances with different characteristic properties.