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TEACHER’S GUIDE TO INQUIRY-BASED TEACHING. Does Mass Change in a Chemical Reaction?. CONCEPTS INTRODUCED IN THIS LESSON SET. Conservation of Mass Open Systems Closed Systems. STUDENT OBJECTIVES.
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TEACHER’S GUIDE TO INQUIRY-BASED TEACHING Does Mass Change in a Chemical Reaction?
CONCEPTS INTRODUCED IN THIS LESSON SET • Conservation of Mass • Open Systems • Closed Systems
STUDENT OBJECTIVES • TSWBAT investigate whether mass stays the same or changes during a reaction that does not include a gas. • TSWBAT investigate whether measuring the mass of reactants and products could provide evidence of whether new substances always come from old substances.
DEFINITION • The principle of “conservation of mass” is that the total mass before a chemical reaction is equal to the total mass after a reaction in a closed system because no material (atom) can enter or leave the system. Material (consisting of atoms) is neither created nor destroyed in chemical reactions.
Instructional Sequence • REVISIT DRIVING QUESTION • INTRODUCE SUB-QUESTION • TAP RECENTLY LEARNED CONCEPTS • ACCESS STUDENT THINKING • ELICIT DESIRED RESPONSES • CONNECT STUDENT UNDERSTANDING • LET’S INVESTIGATE!!! • WRAP UP AND REVISIT SUB-QUESTION
REVISIT THE DRIVING QUESTION • “How can I make new substances from old substances?
INTRODUCE SUB-QUESTION • “Do new substances always come from old substances?”
TAP RECENTLY LEARNED CONCEPTS • “What happens in a chemical reaction?”
ACCESS STUDENT THINKING • Do you think new substances always come from old substances or could they come from somewhere else? • Is there something you can measure to provide evidence for whether new substances come from old substances?
ELICIT DESIRED RESPONSES BY PROVIDING CONNECTIONS • Do you think the mass of the reactant is the same or different than the mass of the products after a chemical reaction? • Remember that the copper and acetic acid had the same mass as the copper acetate and hydrogen gas produced during the reaction in Lesson 8.
CONNECT STUDENT UNDERSTANDING TO SUB-QUESTION • Does measuring mass provide evidence to answer the sub-question - “Do new substances always come from old substances?”
LET’S INVESTIGATE!!! • Activity 13A - Does Mass change when we make gloop? (reaction not including a gas) • Activity 13.1 – Does Mass Change when Alka-Seltzer reacts? (open system) • Activity 13.2 Does Mass Really change when alka-seltzer reacts? (students design closed system)
WRAP UP • Redefine “Conservation of Mass” law – that total mass before a reaction is equal to the total mass after the reaction in a closed system. • Explain that mass is always conserved because atoms can never be created or destroyed. • Connect conservation of mass to other processes such as boiling, freezing, creating mixtures, etc.
REVISIT SUB-QUESTION • Did the last two experiments with Alka-Seltzer support the sub-question? • Since the mass stayed the same in the closed system, this suggests that new substances only come from old substances. Material cannot be created or destroyed. • Homework – write a response to question in the Student Reader 13.2.
THANK YOU! Now let’s investigate conservation of mass!!