1/31/12 A/B DayLEQ: What can happen to the reactants in achemical reaction?1. What is the difference between a natural material and a synthetic one?2. Is steel natural or synthetic?3. Is neon natural or synthetic?4. A scientist is looking for evidence of a chemicalchange. What is one thing he should look for?5. A scientist is looking for evidence of a physicalchange. What is one thing she should look for?
EOG Question:Which of the following may happen during a physical change?A. New substances are formedB. Reactants form productsC. A precipitate is formedD. The temperature may increase
Let’s Review:LAW OF CONSERVATION OF MATTER Matter can’t be _________ and it can’t be _____________.
Today’s LEQ: What can happen to the reactants in a chemical reaction?By the end of today, you should be able to…1. Identify reactants and products2. Apply the law of conservation of matter to chemical reactions3. Identify the creation of gases and precipitates as a part of a chemical reaction
How many words can you make using ONLY the letters below?A A S P M E N RU W T T G O B P
A A S P M E N R U W T T G O B P• Past • Brat• West • Want• Aspen • Poem• Tram • Rap• Pan • Part• We • Sap• Sat • Spent• Men • Grant
Elements are likeletters, compo unds are like
FOCUS VOCABULARY:90. Chemical Reaction91. Reactant92. Product93. Precipitate
Elements are likeletters, compounds are like words. A CLOSER LOOK AT CHEMICAL CHANGES!
Element + Element Compound + Two One WaterHydrogen Oxygen Atoms Atom
CompoundsExplain subscript numbers
DRAW THIS IN YOUR NOTES:Chemical Reaction: process of formingnew substances (a chemical change!)2H + O H 2O H O2
2H + O H2O + Two One WaterHydrogen Oxygen Atoms Atom
DRAW THIS IN YOUR NOTES:Chemical Reaction: process of formingnew substances (a chemical change!)2H + O H 2O H O 2 1 Oxygen2 Hydrogens 1 Water
EOG QUESTION:Carbon combines with oxygen to form carbondioxide. What is the word equation for thischemical reaction? a. carbon dioxide carbon + oxygen b. carbon carbon dioxide + oxygen c. carbon + oxygen carbon dioxide d. carbon dioxide + oxygen carbon
DRAW THIS IN YOUR NOTES:Chemical Reaction: process of formingnew substances (a chemical change!) Reactants Product2H + O H 2O H O 2 1 Oxygen2 Hydrogens 1 Water
Big Numbers vs. Little Numbers H2O 6 H2O ONE WATER 6 WATER MOLECULE MOLECULES -12 hydrogens, -2 hydrogens -6 oxygens -1 oxygen
Big Numbers vs. Little Numbers Reactants Products6 CO2 + 6 H2O C6H12O6 + 6 O26 Carbon 6 Waters 1 Glucose 6 OxygenDioxides particles
BrainPop: Chemical Equations
In your notes…1. Reactants: Products:2. Reactants: Products:3. Reactants: Products:4. Reactants: Products:
EOG QUESTION:If the mass of the reactants in a chemicalreaction is 123.49 grams, what is the massof the products? a. 78.49 grams b. 123.49 grams c. 246.98 grams d. impossible to tell
1. 2 H₂0 ₂ 2 H ₂ 0 + O ₂ 12 g _____?_____2. C3H8 + 5 O2 4 H2O + 3 CO2 4 .5 g + 3.5 g _______?_______3. 4 Al + 3 O2 2 Al2O3 10 g + _?_ 18 g4. 6 CO₂ + 6 H₂OC₆H₁₂O₆ + 6 O₂ 75g + 45 g 10g + __?__
EOG QUESTION:Chemical X has a mass of 5 grams, and chemical Y hasa mass of 10 grams. If the two chemicals are mixedand a complete chemical reaction takes place, what ismost likely the mass of the product? a. 5 grams b. 10 grams c. 15 grams d. 50 grams
How is this possible with the law of conservation of matter?Reactants Products
DEMO: Let’s watch a chemical reaction!
Chemical ReactionsLaw of Conservation of Matter Mass of reactants -chemical ALWAYS EQUALS reactions the mass of the can products! sometimes Ex: form a Reactants = 12 g GAS! Products = 12 g
EOG QUESTION:After a chemical reaction occurs in an open testtube, measurements indicate that the mass of thereactants is greater than the mass of the productsremaining in the test tube. What most likely explainsthe measurements? a. a gas was produced b. a solid was produced c. the salinity of the reactants was high d. the temperature of the reactants was low
What in the world is a precipitate?• http://www.youtube.com/watc h?v=RE- dFN7U91M&feature=related• http://www.youtube.com/watc h?v=pFovlKpPCbI• http://www.youtube.com/watc h?v=Trdyqmzu3JA&feature=rel ated
Chemical ReactionsLaw of Conservation of Matter Mass of reactants -chemical -chemical ALWAYS EQUALS reactions reactions the mass of the can can also products! sometimes form a Ex: form a PRECIPITATE! Reactants = 12 g GAS! (a solid that Products = 12 g forms in a solution)
Summarizer:Consider the following: 2 S2O3 + I2 → S4O6 + 2I1.What are the reactants?2.What are the products?3.If there are 12 grams of reactants in a chemical reaction, what is the mass of the products?4.If you create a chemical reaction in an open test tube and the mass of the reactants is MORE than the mass of the products, what happened?!5.What is a precipitate?