Reactions Physical Change Chemical Change Change in appearance, but not composition. Examples are phase changes, tearing, ripping, color changes (sometimes) Change of one substance into another. Examples include rusting, burning, color change (sometimes).

Reactions Indicators of a chemical change include: - Change in temperature - Gas/Odor given off - Color change - Heat/light given off - Precipitate formed. A precipitate is a solid that comes out of solution

Chemical Equations Another name for a chemical change is a chemical reaction where one or more substances are rearranged to form different substances. Chemists use equations to represent chemical reactions. Coefficient Subscript Parts of a chemical equation: 2H2 + 02 2 H2O Reactants Products Yields

Law of Conservation of Mass and Conservation of Matter The law of conservation of mass states that in a chemical reaction, mass is conserved. That means that the mass you start with must= the mass you end with. Example: CuCl2 + Al AlCl3 + Cu The law of conservation of matter states that the same number and type of atom you start with must = the number and type you end with. 3CuCl2 + 2Al 2AlCl3 + 3Cu 10.2 g 10.2 g =

Balancing Chemical Equations Solid Iron and gaseous chloride react to product a solid iron (III) chloride 1. Write the skeleton equation for the reaction Symbol Meaning + Separates two or more reactants or products  Separates reactants from products (s) Identifies a solid state (l) Identifies a liquid state (g) Identified a gaseous state (aq) Identifies water solution

Symbols for Equations Symbol Meaning +  (s) (l) (g) (aq) Separates two or more reactants or products  Separates reactants from products (s) Identifies a solid state (l) Identifies a liquid state (g) Identified a gaseous state (aq) Identifies water solution

Balancing Chemical Equations Fe(s) + Cl2(g)  FeCl3 2. Count the atoms of the elements in the reactants

Balancing Chemical Equations Fe(s) + Cl2(g)  FeCl3 3. Count the atoms of the elements in the products Reactants Products Fe 1 Cl 2

Balancing Chemical Equations Fe(s) + Cl2(g)  FeCl3 4. Change the coefficients to make the number of atoms of each element equal on both sides of the equation Reactants Products Fe 1 Cl 2 3

Balancing Chemical Equations 2Fe(s) + 3Cl2(g)  2FeCl3 5. Write the coefficients in their lowest possible ratio

Balancing Chemical Equations 2Fe(s) + 3Cl2(g)  2FeCl3 6. Check your work

Al(OH)3(s) + HCl(aq)  AlCl3(aq) + H2O(l)

Types: Combination Combination/ Synthesis/ Composition Def: 2 or more substances react to form 1 product. Usually releases energy, exothermic A + X  AX 4 Fe (s) + 3 O2 (g)  2 Fe2O3 (s) CaO (s) + H2O (l) Ca(OH)2 (s)

CaCO3 (s)  CaO (s) + CO2 (g) Types: Decomposition Def: A single compound breaks down into 2 or more elements or compounds AX  A + X 2NaN3(s)  2Na(s) + 3N2 (g) 2KClO3 (s)  2KCl (s) + 3O2 (g) CaCO3 (s)  CaO (s) + CO2 (g) ***Often Requires and energy source as an initiator. Energy sources can be heat, light, or electricity. Usually endothermic.

Types: Combustion Def: Oxygen gas combines with a substance and releases energy in the form of light or heat. So combustion reactions are usually exothermic. A + O2  C(s) + O2(g)  CO2(g) + energy 4 Fe (s) + 3O2 (g)  2Fe2O3 (s) + energy For hydrocarbons: CxHy + [x + (y/4)] O2  xCO2 + (y/2)H2O C3H8(g) + O2(g)  CO2 (g) + H2O (g) + light + heat

Types: Single Replacement/ Displacement Def: A reaction in which the atoms of 1 element replace the atoms of another element in a compound. A + BX  AX + B, where A = metal OR BX + Y  BY + X, where Y = halogen Li (s) + H2O(l)  LiOH (aq) + H2(g) Cu (s) + 2AgNO3 (aq)  2Ag (s) + Cu(NO3)2 (aq) F2 (g) + 2NaBr(aq)  2NaF(aq) + Br2(l)

Types: Double Replacement/ Displacement Def: 2 compounds exchange ions to produce 2 new compounds. AX + BY  AY + BX K2CO3 (aq) + BaCl2 (aq)  2KCl (aq) + BaCO3 (s) HCl (aq) + NaOH (aq)  H2O (l) + NaCl (aq) 2HI(aq) + Li2S(aq)  H2S(g) + 2LiI (aq)

Bonfire Mass change of substance is evidence

1. 2. Title: Indicators of a Chemical Reaction Concept: Chemical Reactions Descriptions: Each Image would be used to guide students into making a list that describes characteristics of chemical reactions. Characteristics of the reaction in each image are as follows: 1. Fire- smoke, heat energy, light energy, color change of products vs. reactants, and oder 2. Rust- a new substance forms (precipitate), color change of products 3. glowing solutions- fluorescence (color change for them) 4. Angel Cake- the rising dough from the formation of gas bubbles Fire: Copyright- January 2005 Credits- U.S. Department of the Interior, U.S. Geological Survey http://images.google.com/imgres?imgurl=http://sofia.usgs.gov/publications/posters/firefreeze/images/fire-forest.jpg&imgrefurl=http://sofia.usgs.gov/publications/posters/firefreeze/&h=422&w=636&sz=60&hl=en&start=19&tbnid=SMWgCJQ5zd2yKM:&tbnh=91&tbnw=137&prev=/images%3Fq%3Dfire%26start%3D18%26ndsp%3D18%26svnum%3D10%26hl%3Den%26rls%3DRNWN,RNWN:2006-45,RNWN:en%26sa%3DN Rust: Copyright- none provided Credits- Wikipedia http://en.wikipedia.org/wiki/Image:Rust03102006.JPG Fluorescence: http://en.wikipedia.org/wiki/Fluorescence Angel Food Cake: Copyright- 2007 Credits- Allrecipes.com, LatinaCook http://allrecipes.com/Recipe/Angel-Food-Cake-III/Detail.aspx 2.

???Do Now 03/16/07??? Write and balance the given equation. Indicate the type of chemical reaction represented. a. Aluminum metal reacts with hydrochloric acid to produce hydrogen gas and aluminum chloride. b. Iron (III) nitrate reacts with ammonium hydroxide to produce iron (III) hydroxide and ammonium nitrate. c. Ammonium dichromate is heated to produce chromium (III) oxide, nitrogen, and water.

Predicting Products Synthesis/Combination Solid aluminum reacts with solid iodine to produce? Sodium and gaseous chlorine react to form?

Predicting Products Synthesis/Combination Solid magnesium reacts with oxygen gas to produce? Solid iron and chlorine gas react to produce? Fe(III) product

Predicting Products Decomposition Sodium Azide decomposes into? Silver chloride decomposes to produce?

Predicting Products Decomposition Magnesium bromide decomposes into? Cobalt (II) oxide decomposes into?

Predicting Products Combustion Aqueous ethanol (C2H6OH) reacts with oxygen to produce? Solid barium reacts with oxygen to produce?

Predicting Products Combustion Liquid acetone (C3H6O) reacts with oxygen to produce? Solid boron reacts with oxygen to produce?

Replacement/ Displacement Single: A reaction in which the atoms of 1 element replace the atoms of another element in a compound. A + BX  AX + B, where A = metal OR BX + Y  BY + X, where Y = halogen Double: 2 compounds exchange ions to produce 2 new compounds. AX + BY  AY + BX In an aqueous solution and it results in either a gas, a precipitate, or liquid water as one of the products Precipitate: a solid produced during a chemical reaction in a solution.

Single Replacement Activity Series Metals Halogen Activity Series Li K Ca Na Mg Al Zn Fe Ni Sn H Cu Ag Au Most Active F Cl Br I Most Active Least Active F2 (g) + 2NaBr(aq)  2NaF(aq) + Br2(l) Li (s) + H2O(l)  LiOH (aq) + H2(g) Cu (s) + 2AgNO3 (aq)  2Ag (s) + Cu(NO3)2 (aq) Least Active

Predicting Products Single Replacement Iron metal reacts with copper (II) sulfate to yield? Liquid Bromine reacts with magnesium chloride to yield? Magnesium metal reacts with aluminum (III) chloride to yield?

Predicting Products Single Replacement Zinc Metal reacts with sulfuric acid to produce? Iron metal reacts with lead (II) nitrate to yield? Fe (II) product Chlorine gas reacts with sodium iodide to yield?

Predicting Products Double Replacement Calcium Iodide reacts with mercury (II) nitrate to yield? Sulfuric acid reacts with Aluminum hydroxide to yield? Ammonium chloride reacts with silver sulfate to yield?

Predicting Products Double Replacement Barium nitrate reacts with phosphoric acid Iron (II) sulfide reacts with hydrochloric acid #1 on your HW sheet Hydrochloric acid reacts with sodium hydroxide

C2H3OOH(aq) + NaHCO3 (aq)  H2CO3 (aq) + C2H3OONa (aq) Double Displacement: Form: AX + BY  BX + AY Precipitate: K2CO3 (aq) + BaCl2 (aq)  2KCl (aq) + BaCO3 (s) Produce Water: HCl (aq) + NaOH (aq)  H2O (l) + NaBr (aq) Produce Gas: 2HI(aq) + Li2S(aq)  H2S(g) + 2LiI (aq) Demo? Which type of product was formed? 1. baking soda and vinegar C2H3OOH(aq) + NaHCO3 (aq)  H2CO3 (aq) + C2H3OONa (aq) H2CO3 (aq)  H2O (l) + CO2 (g) 2. MgSO4 (aq) + NaOH (aq)  Mg(OH)2 (s) + Na2SO4 (aq)

???Do Now 03/20/07??? Predict the products. Balance the equation. Write the net ionic equation. Au (s) + Al(NO3)3 (aq) K(s) + H2O (l)  H2SO4 (aq) + BaCl2(aq)  AgNO3 (aq) + HCl (aq) 