Once you’re in, you’re in. When the bell rings, voice at zero, working on the Do Now in Do Now Form (flip over the one you have from last week). Pick up daily handouts. Pick up turned back docs. Turn in your MARSHMALLOW ACTIVITY (A LOT ARE MISSING!) TURN IN ANY TEST CORRECTIONS TURN IN YOUR BUBBLE GUM LAB TURN IN TAKE HOME TEST Do Now 10/14/2013 A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O, and 0.675 g H.  What is the empirical formula of the compound? Calculate the number of molecules found in 32 grams of CH4

Do Now Review 10/14/2013 A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O, and 0.675 g H.  What is the empirical formula of the compound? Calculate the number of molecules found in 32 grams of CH4

Tutoring and Makeup Work Tuesday/Thursday 2:30-3:30 Wednesday at Lunch (let me know ahead of time this week) TWO weeks left in the quarter – if your name is on the board , you owe me a quiz or a test!! Zeros

Homework Chemical Reaction Worksheet #7-20 ** Any makeup work / late work Extra Credit Half sheet (percent composition sheet) **graded

Objectives SWBAT 1. Determine empirical formula based on provided element percentages 2. Determine molecular formula when given empirical formula and sample size 3. Conclude reaction type based on provided formulas

Empirical Molecular Review

Write the Empirical Formula for the following problems C6H6 C8H18 WO2 C2H6O2 X39Y13

1. What’s the empirical formula of a molecule containing 65 1. What’s the empirical formula of a molecule containing 65.5% carbon, 5.5% hydrogen, and 29.0% oxygen?

2. If the molar mass of the compound in problem 1 is 110 grams/mole, what’s the molecular formula?

3. What’s the empirical formula of a molecule containing 18 3. What’s the empirical formula of a molecule containing 18.7% lithium, 16.3% carbon, and 65.0% oxygen?

4. If the molar mass of the compound in problem 3 is 73 4. If the molar mass of the compound in problem 3 is 73.8 grams/mole, what’s the molecular formula?

Reaction Types

Combination (Synthesis) Reactions Two or more substances combine to form a new compound. A + X  AX Reaction of elements with oxygen and sulfur Reactions of metals with Halogens Synthesis Reactions with Oxides There are others not covered here!

Decomposition Reactions A single compound undergoes a reaction that produces two or more simpler substances AX  A + X Decomposition of: Binary compounds H2O(l )  2H2(g) + O2(g) Metal carbonates CaCO3(s)  CaO(s) + CO2(g) Metal hydroxides Ca(OH)2(s)  CaO(s) + H2O(g) Metal chlorates 2KClO3(s)  2KCl(s) + 3O2(g) Oxyacids H2CO3(aq)  CO2(g) + H2O(l )

Single Replacement Reactions A + BX  AX + B BX + Y  BY + X Replacement of: Metals by another metal Hydrogen in water by a metal Hydrogen in an acid by a metal Halogens by more active halogens

The Activity Series of the Metals Lithium Potassium Calcium Sodium Magnesium Aluminum Zinc Chromium Iron Nickel Lead Hydrogen Bismuth Copper Mercury Silver Platinum Gold Metals can replace other metals provided that they are above the metal that they are trying to replace Metals above hydrogen can replace hydrogen in acids. Metals from sodium upward can replace hydrogen in water

The Activity Series of the Halogens Halogens can replace other halogens in compounds, provided that they are above the halogen that they are trying to replace. Fluorine Chlorine Bromine Iodine 2NaCl(s) + F2(g)  ??? 2NaF(s) + Cl2(g) MgCl2(s) + Br2(g)  ??? No Reaction

Double Replacement Reactions The ions of two compounds exchange places in an aqueous solution to form two new compounds. AX + BY  AY + BX One of the compounds formed is usually a precipitate, an insoluble gas that bubbles out of solution, or a molecular compound, usually water.

Combustion Reactions A substance combines with oxygen, releasing a large amount of energy in the form of light and heat. Reactive elements combine with oxygen P4(s) + 5O2(g)  P4O10(s) (This is also a synthesis reaction) The burning of natural gas, wood, gasoline ENDED PD 1 C3H8(g) + 5O2(g)  3CO2(g) + 4H2O(g)

Acid-Base Reactions This is a special kind of double displacement reaction that takes place when an acid and base react with each other. The H+ ion in the acid reacts with the OH- ion in the base, causing the formation of water. Generally, the product of this reaction is some ionic salt and water: HA + BOH ---> H2O + BA One example of an acid-base reaction is the reaction of hydrobromic acid (HBr) with sodium hydroxide: HBr + NaOH ---> NaBr + H2O

Exit Ticket 1. 2 NO2  2 O2 + N2 Reaction Type ______________________ 2. C5H5 + Fe  Fe(C5H5)2 Reaction Type _______________________ 3. CaCO3  CaO + CO2 Reaction Type _______________________