Catalyst – September 2(11), Label the following as either a pure substance (PS) mixture (M): a) Salt water b) Hydrogen c) Salad 2. Dr. Spock performed a reaction in space. The mass of the reactants was 46.3 grams. The mass of the products was 77.5 grams. Did Dr. Spock’s reaction obey the LCM? Why or why not?

Today’s Agenda  Catalyst  Quiz Mastery Tracking  Finish planning LCM Lab  LCM Lab and Lab Report  Exit Question

Today’s Objectives  SWBAT plan and conduct an experiment to prove the Law of Conservation of Matter.

Law of Conservation of Matter (LCM) Key Point #1: The Law of Conservation of Matter states that matter cannot be created or destroyed, only changed from one form of matter to another. What goes in must come out!

LCM and Physical Changes # Particles Beginning Stuff = # Particles Ending Stuff Mass Beginning Stuff = Mass Ending Stuff Cut

LCM and Physical Change # Particles Beginning Stuff = # Particles Ending Stuff Mass Beginning Stuff = Mass Ending Stuff Dissolve

LCM and Chemical Change Mass Reactants = Mass Products Chemical Reaction New Substance

LCM and Chemical Change Mass Reactants = Mass Products Chemical Reaction Particles Rearrange

Example of a Good Conclusion The reaction between baking soda and vinegar does obey the Law of Conservation of Matter. The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products. At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products. These masses are very similar/the same; therefore the reaction obeyed the LCM. (The masses are not exactly the same because of experimental error.)

Example of a Good Conclusion “The reaction between baking soda and vinegar does obey the Law of Conservation of Matter.” This is the statement of what you think!!!

Example of a Good Conclusion The reaction between baking soda and vinegar does obey the Law of Conservation of Matter. The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products. At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products. These masses are very similar/the same; therefore the reaction obeyed the LCM. (The masses are not exactly the same because of experimental error.)

Example of a Good Conclusion “The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products.” This explains background information – helps support your conclusion.

Example of a Good Conclusion The reaction between baking soda and vinegar does obey the Law of Conservation of Matter. The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products. At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products. These masses are very similar/the same; therefore the reaction obeyed the LCM. (The masses are not exactly the same because of experimental error.)

Example of a Good Conclusion “At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products.” This is what happened in the experiment.

Example of a Good Conclusion The reaction between baking soda and vinegar does obey the Law of Conservation of Matter. The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products. At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products. These masses are very similar/the same; therefore the reaction obeyed the LCM. (The masses are not exactly the same because of experimental error.)

Example of a Good Conclusion “These masses are very similar/the same; therefore the reaction obeyed the LCM.” This ties back into what you think!

Example of a Good Conclusion The reaction between baking soda and vinegar does obey the Law of Conservation of Matter. The LCM states that matter cannot be created or destroyed. That means that the mass of the reactants should equal the mass of the products. At the start of this reaction, there were ## grams of reactants. After the reaction, there were ## grams of products. These masses are very similar/the same; therefore the reaction obeyed the LCM. (The masses are not exactly the same because of experimental error.)

Can YOU prove the LCM?  In your group, you will plan a procedure for proving the Law of Conservation of Matter  You will perform the lab tomorrow  You may perform ONE of the following reactions:  Baking soda + vinegar  Alka Seltzer + water  You must complete an entire Lab Report for Homework (due Tuesday in class or Wednesday at the beginning of class)

Available Materials  Balance  Graduated cylinder  Beaker  Zip-Loc baggie  Funnel  Spatula  Petri dish  Test Tubes  Glass stirring rod  1 Alka Seltzer tablet  Up to 25 mL of water  Up to 3 grams of baking soda  Up to 25 mL of vinegar

Exit Question The goal of a car airbag is to slow a passenger's forward motion as evenly as possible in a fraction of a second. The airbag's inflation system reacts toxic sodium azide (NaN 3 ) with potassium nitrate (KNO 3 ) to produce nitrogen gas and sodium metal. Hot blasts of the nitrogen inflate the airbag. In a Honda Civic, there are about 500 grams of sodium azide (NaN 3 ) in its airbag before inflation. It decomposes to 323 grams of nitrogen gas. Question: How much sodium metal is produced? Your Task: Answer the question and support your answer with a quality conclusion.