 Notes #19 Chapter 11.1, 11.2, and 11.3

On May 6, 1937, the huge airship Hindenburg erupted into a fireball. Within a short time, 210,000 cubic meters of hydrogen had burned and the airship was destroyed. The chemical reaction that occurred is “hydrogen combines with oxygen to produce water.” You will learn to represent this chemical reaction by a chemical equation.

 Reactants  Products  Reactant + Reactant  Product + Product  Examples: o Iron + Oxygen  Iron (III) Oxide o Hydrogen Peroxide  water + oxygen o Methane + oxygen  carbon dioxide + water

 How could we describe the rusting of iron?

o Iron + Oxygen  Iron (III) Oxide o Hydrogen Peroxide  water + oxygen o Methane + oxygen  carbon dioxide + water  What are they as chemical equations? o Fe (s) + O 2 (g)  Fe 2 O 3 (s) o H 2 O 2 (aq)  H 2 O (l) + O 2(g) o CH 4(g) + O 2(g)  CO 2(g) + H 2 O (l)

A catalyst is a substance that speeds up the reaction but is not used up in the reaction. Without Catalyst With Catalyst

 Coefficients—small whole numbers that are placed in front of the formulas in an equation in order to balance it.  Coefficients are JUST for balancing the equation.  Subscripts are used to identify the correct chemical formula. They DO NOT CHANGE.

 Practice:  H 2(g) + O 2(g)  H 2 O (l)  Al (s) + O 2(g)  Al 2 O 3(s)  CS 2 + Cl 2  CCl 4 + S 2 Cl 2  P + O 2  P 4 O 10  Al + N 2  AlN  NaNO 3 + PbO  Pb(NO 3 ) 2 + Na 2 O  Fe 2 O 3 + H 2  Fe + H 2 O

 Get out 3 pieces of paper  Make a flipbook organizer. (See Mrs. Branum’s!)  Space paper 1 inch apart and fold.  Staple your organizer  Name the organizer: Types of Reactions  You have 5 minutes

 General Equation: R +S  RS  Reactants: Generally two elements or two compounds COMBINE  Product: A single compound  Example: 2Mg(s) + O 2 (g)  2MgO(s)

 General Equation: RS  R + S  Reactants: A single binary compound or compound with a polyatomic ion.  Products: Two or more elements  Example: 2HgO(s)  2Hg(l) + O 2 (g)

 General Equation: T + RS  TS + R  Reactants: An element and a compound  Products: a different element and a new compound  Example: Zn + AgNO 3  Ag + Zn(NO 3 ) 2

 General Equation: R + S - + T + U -  R + U - + T + S -  Reactants: Two ionic compounds. They exchange their ions.  Products: Two new compounds. A reaction has occurred when we see a precipitate.  Example: K 2 CO 3 (aq) + BaCl 2 (aq)  2KCl(aq)+ BaCO 3 (s)

 General Equation: C x H y + (x+(y/4))O 2  xCO 2 + (y/2)H 2 O  Reactants: Oxygen and a compound that contains C and H  Products: CO 2 and H 2 O  Example: CH 4 (g) + 2O 2 (g)  CO 2 (g) + 2H 2 O(g)

o What type of reaction is described by the following equation? o Add these examples to your flip organizer in the appropriate spot! o 6Li + N 2  2Li 3 N o 2C 8 H 18 (l) + 25 O 2 (g)  16CO 2 (g) + 18H 2 O(l) o 2NaCN(aq) + H 2 SO 4 (aq)  2HCN(s) + Na 2 SO 4 (aq) o 2HgO(s)  2 Hg(l) + O 2 (g) o Br 2 (aq) + NaI(aq)  NaBr(aq) + I 2 (aq)

 chemical-reactions-video-tsinghua_n_ html chemical-reactions-video-tsinghua_n_ html  What happens when chemistry is used t make ART?  See beautifulchemistry.net for more information

 Now that you have learned about some of the basic reaction types, you can predict the products of many reactions.  Use your flip book as a guide  The number of elements and/or compounds is a good indicator of possible reaction type and thus the possible products. (USE YOUR FLIPBOOK)

o Predict the products for the following reactions and balance the equations: o Al + Cl 2  o C 2 H 2 + O 2  o Ag + HCl  o MgCl 2  o CaI 2 + Hg(NO 3 ) 2  o Na 2 S + Cd(NO 3 ) 2 

 Aqueous solutions  It means something is dissolved in water!  Example:  AgNO 3 (aq) + NaCl(aq)  AgCl(s) + NaNO 3 (aq)  (aq) means it is dissolved in water.  Why is there a solid? (s)  It represents that a reaction has occured.

 Whenever a solid is formed, we call this a precipitate  To show this reaction, we do the NET IONIC EQUATION. Beginning Equation: AgNO 3 (aq) + NaCl(aq)  AgCl(s) + NaNO 3 (aq) Complete Ionic Equation: Ag + (aq) + NO 3 - (aq) + Na + (aq) + Cl - (aq)  AgCl(s) + Na + (aq) + NO 3 - (aq)

 Cancel out spectator ions on each side: Never cancel out the solid.  When that happens, you will have your NET IONIC EQUATION  It only shows what is important.  Ag + (aq) + Cl - (aq)  AgCl(s)  A REACTION ONLY OCCURS IN AQUEOUS SOLUTIONS WHEN A PRECIPITATE FORMS.

 Give the net ionic equation: o Na 3 PO 4 (aq) + FeCl 3 (aq)  NaCl(aq) + FePO 4 (s)

 of-Chemistry-.htm of-Chemistry-.htm  Article Reading: The Science of Pain  Group Activity: o In groups of 2-4, record 4 ways in which chemical reactions are important to YOU. o Be specific. Give specific examples.

 Grab a post it! Write your name on the back.  Explain: two ways in which chemical reactions are important environmentally, globally, ethically, or economically.  Post on classroom door before leaving the classroom.