Bell Work 11-30-15 What do you use to convert grams to moles or moles to grams? What do you use to convert particles(atoms, molecules, units) to moles or vice versa? If I am changing from grams to particles what do I need to do? Convert 184g of PbI2 to particles.

Extra Credit-Memes! Create a meme that is related to chemistry. To create a meme, go to a meme generator website. Choose a blank meme and add your own text. After you have created a meme save the image. Either email me or print the image. You need to include 2-3 sentences describing the science behind your meme and why it is funny and clever. DUE BY MONDAY, DECEMBER 7

Unit 6: Chemical Reactions

What are indications that a chemical reactions has happened?

Bell Work 12-1-15 List 5 things that would indicate a chemical reaction has occurred.

Indicators of chemical reactions Emission of light or heat Formation of a gas Formation of a precipitate Color change Emission of odor

All chemical reactions: Have two parts Reactants - the substances you start with 2. Products- the substances you end up with The reactants turn into the products Reactants ® Products

Describing Chemical Reactions Can be described several ways: 1. In a sentence Copper reacts with chlorine to form copper (II) chloride. 2. In a word equation Copper + chlorine ® copper (II) chloride Cu + Cl2 ® CuCl2

Symbols used in equations (s) after the formula –solid Cu(s) (g) after the formula –gas H2 (g) (l) after the formula -liquid H2O(l) (aq) after the formula - dissolved in water, an aqueous solution. CaCl2 (aq) Cu(s) + Cl2(g) ® CuCl2(aq)

Symbols used in equations indicates a reversible reaction shows that heat is supplied to the reaction

Diatomic elements There are 7 elements that never want to be alone. They form diatomic molecules, in gas state. H2 , N2 , O2 , F2 , Cl2 , Br2 , and I2

Law of Conservation of Mass In a chemical reaction, matter is neither created nor destroyed. Atoms won’t change their identity (e.g. a Carbon atom can’t become an Iron atom) This means that you have to have the same number of each type of atom on each side of the chemical equation.

Law of Conservation of Mass Atoms cannot be created or destroyed! Total mass stays the same. The atoms are rearranged to form new materials.

Balancing Equations We can see that the equation, does not follow the Law of Conservation of Mass C2 + O2  CO2 We can see that on the product side there are two carbon atoms, but on the reactant side there is only one. This cannot possibly happen, as mass cannot be destroyed

Balancing Equations To balance chemical equations follow these basic steps Perform an atom inventory—count how many of each element you have on each side of the arrow. Identify your problem areas Begin adjusting the coefficients of the equation to balance the equation. You cannot change the subscripts, only the coefficients!

Balancing Equations C2 + O2  CO2 Atom inventory Identify Problems Fix Problems

WARNING! Don’t mess with the insides of polyatomic ions – put a square around them, or label them as X – treat the WHOLE polyatomic ion as though it were an element! Don’t ever play around with subscripts (those little numbers that tell you how many atoms are in a molecule) e.g. C6H22O11

7. H2 + Cl2  HCl 1H2 + 1Cl2  2HCl

8. CdCO3  CdO + CO2 Already Balanced 

4. Li + FeBr2  LiBr + Fe 2Li + 1FeBr2  2LiBr + 1Fe

3. KClO3  KCl + O2 2KClO3  2KCl + 3O2

NaOH + FeCl3  NaCl + Fe(OH)3 5. NaOH + FeCl3  NaCl + Fe(OH)3 3NaOH + 1FeCl3  3NaCl + 1Fe(OH)3

2. Na + H2O  NaOH + H2 2Na + 2H2O  2NaOH + 1H2

6. Ca2Br2 + NaCO3  CaCO3 + NaBr 1Ca2Br2 + 2NaCO3  2CaCO3 + 2NaBr

Bell Work 12-6-15 Balance the following equations: 1.___Al2(SO4)3 +___ Ca(OH)2 →__ Al(OH)3 + __ CaSO4 2. ___Cr +___ O2 →____ Cr2O3

Types of Reactions Synthesis reactions Decomposition reactions Single displacement reactions Double displacement reactions Combustion reactions

1. Synthesis General: A + B  AB Example C + O2  + O O Definition: multiple reactants combine to form a single product http://www.youtube.com/watch?v=uCwHzTsx5yY

2. Decomposition General: AB  A + B Example: NaCl  + Cl Na Cl Na Definition: breakdown of one molecule into elements or simple compounds http://www.youtube.com/watch?v=ImWpJienMRA

3. Single Displacement/Replacement Example: Zn + CuCl2  Zn Cl Cu + Cl Zn Cu + General: AB + C  AC + B Definition: an element or ion is replaced by another in a compound

4. Double displacement General: AB + CD  AD + CB Example: MgO + CaS  Definition: two elements or ions are replaced by another in multiple compounds

5. Combustion Reactions Definition: a hydrocarbon reacts with oxygen gas. This is also called burning!!! In general: CxHy + O2  CO2 + H2O Products are ALWAYS carbon dioxide and water.

Bell Work 12-8-15 1.Balance the equation 2. What type of reaction? _____ Ca + _____ O2  _____ CaO Reaction: _______________ _____ Cu2O + _____ C  _____ Cu + _____ CO2 _____ Na + _____ MgF2  _____ NaF + _____ Mg _____ Na + _____ HCl  _____ H2 + _____ NaCl _____ Cl2 + _____ KI  _____ KCl + _____ I2

Activity Series. Elements will replace elements below them in single rep. reactions. K Ca Na Mg Al Zn Fe Ni Pb H Cu Ag

Solubility Table Ion Solubility Exceptions NO3– soluble none ClO4– Cl–   except Ag+, Hg22+, *Pb2+ I– SO42- except Ca2+, Ba2+, Sr2+, Hg2+, Pb2+, Ag+ CO32- insoluble except Group IA and NH4+ PO43- OH– except Group IA, *Ca2+, Ba2+, Sr2+ S2- except Group IA, IIA and NH4+ Na+ K+ NH4+

AgNO3(aq) CuSO4(aq) Li3N NH4NO3