Catalyst – October 3+ 18, 2010 FUN GRAPH FRIDAY! 1. In what month do you think red light cameras were installed in Renton, WA? 2. What do you think happened to cause a decrease in citations (tickets) issued? Red light cameras were installed in Renton, WA and this graph shows the number of citations issued each month.
Today’s Agenda Catalyst Projects into Ms. Stroh Scavenger Hunt Notes College Presentation Exit Question GOOD LUCK TO ACT TAKERS!
Today’s Objectives SWBAT begin to apply law of conservation of mass to chemical reactions by balancing chemical equations.
SCAVENGER HUNT!
Whiteboard Practice How many total atoms of each element are in these compounds? AlCl 3 : Al = ? Cl = ? H 2 O: H = ? O = ? H 2 O 2 : H = ? O = ? KCl: K = ? Cl = ? Be 3 S 2 : Be = ? S = ? NH 4 NO 3 : N = ? H = ? O = ?
Balancing equations RULES! Key Point #1: When balancing equations, never, Never, NEVER change subscripts, only coefficients!
Yo, Ms. Stroh What is a coefficient? GOOD QUESTION!
Coefficient A coefficient is a whole number that comes in front of the compound formula, never in the middle! You multiply the coefficient to all the numbers in the compound 2 AlCl 3
Do you get it? 3 AlCl 3 How many atoms of each element do they have? 3 Aluminum atoms 9 Chlorine atoms
How many of each atom do we have now? 7 AlCl 3 4 H 2 O 6 H 2 O 2 5 KCl 2 Be 3 S 2 4 (NH 4 )NO 3
Why is the top equation wrong? You figure it out (5 min) We never want to leave an equation written like this… H 2 + O 2 H 2 O We want to have it like this… 2 H 2 + O 2 2 H 2 O WHY???
L-C-M!!! Key Point #2: Chemical reactions MUST follow the Law of Conservation of Matter. What is the LCM? Matter cannot be created or destroyed. If 3 carbons are in the reactants of a reaction, then there darn well better be 3 carbons in the products of a reaction.
Balancing Chemical Reactions H 2 + O 2 H 2 O __H__ __O__ Write down elements.
Balancing Chemical Reactions H 2 + O 2 H 2 O __H__ __O__ How many are there?
Balancing Chemical Reactions H 2 + O 2 H 2 O _2_H_2_ __O__ How many are there?
Balancing Chemical Reactions H 2 + O 2 H 2 O _2_H_2_ _2_O_1_ How many are there?
Balancing Chemical Reactions H 2 + O 2 H 2 O _2_H_2_ _2_O_1_ Get number equal!
Balancing Chemical Reactions Try These: N 2 + H 2 NH 3 P 4 O 10 + H 2 O H 3 PO 4 Ca 3 P 2 + H 2 O Ca(OH) 2 + PH 3
Balancing Chemical Reactions Try These: N 2 + 3H 2 2NH 3 P 4 O 10 + H 2 O H 3 PO 4 Ca 3 P 2 + H 2 O Ca(OH) 2 + PH 3
Balancing Chemical Reactions Try These: N 2 + 3H 2 2NH 3 P 4 O H 2 O 4H 3 PO 4 Ca 3 P 2 + H 2 O Ca(OH) 2 + PH 3
Balancing Chemical Reactions Try These: N H 2 2NH 3 P 4 O H 2 O 4H 3 PO 4 Ca 3 P 2 + 6H 2 O 3Ca(OH) 2 + 2PH 3
COLLEGE PRESENTATION???
Exit Question Balance the following equations: 1. __KClO 3 ---> __KCl + __O 2 2. __S + __O 2 ---> __SO 3 Leave Notes in Folder Please! GOOD LUCK ACT TEST TAKERS!!