Blowing Up Balloons, Chemically
Summary
Students will:
understand and apply the Law of Conservation of Matter;
balance chemical equations;
use the following skills: observing and recording data (observations) and making inferences from observations.
CollapseLearning Goals
The Law of Conservation of Matter says that matter can neither be created or destroyed, but can be changed in form. In other words, the total mass of the material(s) before the reaction is the same as the total mass of material(s) after the reaction. Students will determine what observable factors are changed in a chemical reaction and what factors remain constant.
Context for Use
Use in High School General Chemistry class of any size. Students work in pairs.
Description and Teaching Materials
Students will work in a lab setting investigating the Law of Conservation of Matter using observation and data collecting and answering inquiry based questions.
EXPERIMENTAL PROCEDURE - see attachment.
DATA SHEET - see attachment.
QUESTIONS – THINKING SCIENTIFICALLY - see attachment.
Chemicals and Equipment Needed:
250 ml flask, balloon, balance, acetic acid, hydrochloric acid, sodium bicarbonate, zinc
Zinc can be obtained by melting pennies over a Bunsen burner. The penny has a copper coat over a zinc core. Pennies can be cut into small pieces with shears for this lab. The small amount of copper will make no difference in the final outcome.
Hydrochloric acid is sold as "muriatic acid" by commercial cleaning supply companies. It may be as strong as 12 M. It must be diluted to 3 M for this lab.
Food coloring may be added to the acids. This helps avoid the problem of students using the wrong acid and may result in reactions that have interesting color changes. Student Handouts (Microsoft Word 26kB Aug2 09)
EXPERIMENTAL PROCEDURE - see attachment.
DATA SHEET - see attachment.
QUESTIONS – THINKING SCIENTIFICALLY - see attachment.
Chemicals and Equipment Needed:
250 ml flask, balloon, balance, acetic acid, hydrochloric acid, sodium bicarbonate, zinc
Zinc can be obtained by melting pennies over a Bunsen burner. The penny has a copper coat over a zinc core. Pennies can be cut into small pieces with shears for this lab. The small amount of copper will make no difference in the final outcome.
Hydrochloric acid is sold as "muriatic acid" by commercial cleaning supply companies. It may be as strong as 12 M. It must be diluted to 3 M for this lab.
Food coloring may be added to the acids. This helps avoid the problem of students using the wrong acid and may result in reactions that have interesting color changes. Student Handouts (Microsoft Word 26kB Aug2 09)
Teaching Notes and Tips
Teacher will review basic principles of precision and accuracy. Students will have basic knowledge of significant figures and balancing chemical equations. Instructor will introduce Lavoisier's classic experiments. Instructor will review vocabulary and exothermic and endothermic reactions.
If time is limited, the class may be divided into two groups, with one group assigned to do the reaction with zinc and hydrochloric acid and the other group with sodium bicarbonate and acetic acid [vinegar].
Goals:
The Law of Conservation of Matter says that matter can neither be created or destroyed, but can be changed in form. In other words, the total mass of the material(s) before the reaction is the same as the total mass of material(s) after the reaction. Students will determine what observable factors are changed in a chemical reaction and what factors remain constant.
Concepts
Law of Conservation of Matter.
Precision in measurements.
Accurate recording of data.
Vocabulary to Review:
Reagents
Endothermic
Exothermic
Reactants
Products
Closed system
If time is limited, the class may be divided into two groups, with one group assigned to do the reaction with zinc and hydrochloric acid and the other group with sodium bicarbonate and acetic acid [vinegar].
Goals:
The Law of Conservation of Matter says that matter can neither be created or destroyed, but can be changed in form. In other words, the total mass of the material(s) before the reaction is the same as the total mass of material(s) after the reaction. Students will determine what observable factors are changed in a chemical reaction and what factors remain constant.
Concepts
Law of Conservation of Matter.
Precision in measurements.
Accurate recording of data.
Vocabulary to Review:
Reagents
Endothermic
Exothermic
Reactants
Products
Closed system
Assessment
Evaluate each student's work using the Science Rubrics:
Knowledge: The student showed appropriate and correct connections to concepts and observations.
Application: The investigation was completed safely and observations were recorded correctly.
Communication: Data and answers to questions were complete and accurate.
Knowledge: The student showed appropriate and correct connections to concepts and observations.
Application: The investigation was completed safely and observations were recorded correctly.
Communication: Data and answers to questions were complete and accurate.
Standards
8.2.1.2.1
8.2.1.2.2
Substances can undergo physical and/or chemical changes which may change the properties of the substance but do not change the total mass in a closed system.
8.2.1.2.2
Substances can undergo physical and/or chemical changes which may change the properties of the substance but do not change the total mass in a closed system.