WHAT DO ALL THESE THINGS HAVE IN COMMON?

Oxidation and Reduction +1 -1 2Na0 + Cl202NaCl O I L Oxidation is loss of electrons or… xidation s osing Na01e- + Na+1 (Half reaction) Na is oxidized.

R I G 2Na0 + Cl202NaCl Cl0 + 1e-Cl-1 eduction s aining Oxidation and Reduction +1 -1 2Na0 + Cl202NaCl R I G Reduction is gain of electrons or… eduction s aining Cl0 + 1e-Cl-1 (Half reaction) Cl is reduced.

LEO says GER

2Na0 + Cl202Na+1Cl-1 Secret Agent Man Cl Na R.A. O.A. Here’s a little trick Secret Agent Man OIL RIG Oxidizing agent (O.A.) causes a particle to lose e- (by gaining e- itself) Reducing agent (R.A.) causes another particle to gain e- (by losing e- itself) Cl Na Particle Oxidized Particle Reduced R.A. O.A. 2Na0 + Cl202Na+1Cl-1

2Na0 + Cl202Na+1Cl-1 The particle oxidized and the particle reduced are ALWAYS on the same side of the equation! AND the oxidizing agent and reducing agent are ALWAYS on the same side of the equation OIL RIG

So happy togetherrrrrr! Oxidation and reduction always occur together

Ca + S Ca S Practice +2 -2 Ca S Ca S OIL RIG R.A. O.A. Then identify: +2 -2 OIL RIG Ca + S Ca S R.A. O.A. 1. Assign charges. 2. Particle oxidized ____ 3. Particle reduced ____ 4. Oxidizing agent _____ 5. Reducing agent ____ Then identify: Ca OIL S RIG Ca R.A. S O.A.

Mg + Cl2 Mg Cl2 Practice -1 +2 Mg Cl Mg Cl OIL RIG R.A. O.A. RIG +2 Mg + Cl2 Mg Cl2 R.A. O.A. Assign charges. 2. Particle oxidized ____ 3. Particle reduced ____ 4. Oxidizing agent _____ 5. Reducing agent ____ Then identify: Mg OIL Cl RIG Mg R.A. Cl O.A.

Mg Cl2 Oxidation States -1 +2 Oxidation states indicates how many e- are gained, lost, or shared. Oxidation states Mg Cl2 +2 -1

Rules for Naming Oxidation States 1. In their compounds, the metals of Group 1A always have an oxidation number of +1, the charge on their ions 2. The oxidation number of fluorine (F) is - 1 when it is in a compound. +1 -1 NaBr GIVE RULES SHEET AND RULES W.S. HAVE THEM WORK ON RULES W.S. IN CLASS USING RULES AS REFERENCE GO OVER W.S. QUICKLY GO THROUGH RULES; STAR #1, #2, #5, #7 BECAUSE THEY ARE AN ALWAYS. GIVE “OXIDATION STATES” WORKSHEET FOR HOMEWORK…START IN CLASS +1 -1 CuF

Rules for Naming Oxidation States 3. The oxidation number of a monatomic ion is equal to its charge. Fe+3….Oxidation # = +3

Rules for Naming Oxidation States 4. The sum of the oxidation numbers of all the atoms in the formula of a compound is equal to zero. 5. In their compounds, the metals of group 2A always have an oxidation number of +2, the charge on their ions. +1 -2 K2Se +1(2) + -2 = 0 +2 + -2 = 0 K will always be +1 because it is in group 1 +2 -2 CaS +2 + -2 = 0

Rules for Naming Oxidation States 6. In compounds, the oxidation number of oxygen is almost always -2. (Exception: peroxides such as H2O2 or Na2O2 where oxidation number is -1 +1 -1 +1 -1 Na2O2 H2O2 2(+1) + 2(-1) = 0 +2 + -2 = 0 2(+1) + 2(-1) = 0 +2 + -2 = 0

Rules for Naming Oxidation States 7. The oxidation number of an atom of a free element is zero. 8. Hydrogen has an oxidation number of +1 in all compounds, except the metal hydrides, like LiH or CaH2, where oxidation number is -1. Na0 Br20 HF KH +1 -1 Metal hydride

Rules for Naming Oxidation States 9. In combinations involving nonmetals, the oxidation number of the less electronegative element is positive and of the more electronegative element is negative. +2 -3 +4 -2 SO2 Fe3P2 +4 + 2(-2) = 0 +4 + -4 = 0 3(+2) + 2(-3) = 0 +6 + -6 = 0

Rules for Naming Oxidation States 10. The algebraic sum of the oxidation numbers of the atoms of a polyatomic ion is equal to its charge. -2 ( ) = the whole ion (S & 3 O’s) have a charge of -2 SO3 -2 SO3 ( ) +4 -2 ___ + -6 = -2 +4

Polyatomic Ions Some covalently bonded groups of atoms act like single atoms in forming ions. These charged groups of covalently bonded atoms are called radicals or polyatomic ions. SULFITE: SO3-2 AMMONIUM: NH4+1 SULFATE: SO4-2 HYDRONIUM: H3O+1 CHLORITE: ClO2-1 HYDROXIDE: OH-1 CHLORATE: ClO4-1 CYANIDE: CN-1 CHROMATE: CrO4-2 PHOSPHATE: PO4-3

Practice: assign oxidation states (numbers). +2 -2 +1 -1 NaCl MgS Al ZnO H2 CrF2 +2 -2 = 0 +1 -1 = 0 +2 -2 1-3 on ws +2 -2 = 0 +2 -1 +2 + 2(-1) = 0 +2 -2 = 0

Practice: Assign oxidation states (charges). +3 -2 +1 -1 Fe2O3 K2O2 NO2 HBr SrH2 MnBr2 +1 + -1 = 0 +6 + -6 = 0 +2 -1 +1 -1 *Metal hydride *peroxide +2 + -2 = 0 Do 7 +2 + -2 = 0 +2 -1 +4 -2 +2 + -2 = 0 +4 + -4 = 0

Practice: assign oxidation states (charges). -2 +1 -2 +3 (OH) -1 (Cr2O4)-2 -2 + ___ = -1 +1 ____ + 4 (-2) = -2 ___ + -8 = -2 +6 2(___) + -8 = -2 +3 +2 -2 PRACTICE! (S2O3)-2 ___ + 3 (-2) = -2 ___ + -6 = -2 +4 2(___) + -6 = -2 +2

Practice: assign oxidation states (charges). +1 +6 -2 ? H2SO4 1(2) + 1x + 4(-2) = 0 2 + 1x + -8 = 0 1x + -6 = 0 Number 4 on sheet 1x = +6 x = +6 +2 +6 + -8 = 0 +8 + -8 = 0

Practice: assign oxidation states (charges). +1 +7 -2 1(+1) + 1x + 4(-2) = 0 HClO4 K2Cr2O7 1 + 1x -8 = 0 +1 +7 -8 = 0 1x = +7 x = +7 +1 +6 -2 2(+1) + 2x + 7(-2) = 0 PRACTICE! +2 +12 -14 = 0 2 + 2x -14 = 0 2x = +12 x = +6

Writing a Formula Al+3 S-2 Al2+3S3-2 = Al2S3 Rb+1 N-3 = Rb3+1N-3 Rb3N1 Write down elements with their oxidation numbers. *More electronegative is written last. Al+3 S-2 Al2+3S3-2 = Al2S3 2(+3) + 3(-2) +6 -6 = 0 Rb+1 N-3 = Rb3+1N-3 Rb3N1 3(+1) + 1 (-3) +3 -3 = 0

Polyatomic Ions in Compounds Potassium + chlorite Calcium + chromate Magnesium + hydroxide K+1 & (ClO2)-1 = KClO2 +1 -1 = 0 Ca+2 & (CrO4)-2 = CaCrO4 +2 -2 = 0 Mg+2 & (OH)-1 = Mg(OH)2 *Leave polyatomic in parenthesis! +2 + 2(-1) = 0

Writing Chemical Formulas Li+1I-1 LiI Li and I K and P Rb and C Li and Cr2O7-2 K+1P-3 K3P PRACTICE Rb+1C-4 Rb4C Li+1(Cr2O7)-2 Li2Cr2O7

CHEMICAL REACTIONS & EQUATIONS

Chemical Reactions

Chemical Reactions Process in which one or more substances are converted into new substances with different physical and chemical properties For example, a yellow solid precipitate, lead iodide (PbI2), forms from the mixture of two clear liquids, potassium iodide (KI) and lead nitrate (Pb(NO3)2).

Word Equation Hydrogen + Oxygen Water + Energy Reactants Products

Balanced Formula Equations 2 H2 (g) + O2 (g) 1 2 H2O (l) Why? To give a quantitative, as well as qualitative information.

2H2 (g) + 1O2 (g) 2H2O (l) 2 Molecules Water 2 Molecules H + 1 molecule O + 2 Moles H2 + 1 Mole O2 2 Moles Water 4 g 32 g + 36 g

Rules for Balancing Equations 1. Write correct formulas for all reactants and products. Use the symbols for elements: Iron = Fe Don’t forget diatomic elements travel in pairs! H2, N2, O2, F2, Cl2, Br2, I2

Rules for Balancing Equations 2. Obey the LAW OF CONSERVATION OF MASS. Same number of each kind of atom on both sides of the equation. 25g + 25g + 50 g 50 g + 150 g ?g

How to Balance an Equation 3. To balance atoms of reactants and products, change ONLY the coefficients. 4. Do NOT change the chemical formula to balance numbers of atoms. Numbers IN FRONT of the formulas NOTE: Subscripts are lower numbers in formula 4 Al2O3 Coefficient Subscripts

How to Balance an Equation cont. 5. Check your work by counting atoms of each element. 6. Check to see that the coefficients are in the lowest whole number ratio. 2H2O (l) 2H2 (g) + 1O2 (g) 4 Hydrogen 4 Hydrogen 2 Oxygen 2 Oxygen

Practice Balancing These Equations 2 1 2 Ca + O2 CaO 1 Ca 1 Ca 2 O 1 O *Hint: Start by making the uneven side even. 2 O 2 O 1 Ca 2 Ca 2 Ca 2 Ca 2 O 2 O 2 Ca, 2 O 2 Ca, 2 O

Practice 1 1 2 2 CH4 + O2 CO2 + H2O 2 O 3 O 4 O 4 O 1 C 1 C 4 H 4 H *Hint: Start with the element that is split up: Oxygen. Then, make uneven side even. 2 O 3 O 4 O 4 O 1 C 1 C 4 H 4 H 1 C, 4 H, 4 O 1 C, 4 H, 4 O

Practice 2 Fe + Cl2 FeCl3 2 1 3 1 Fe 1 Fe 2 Cl 3 Cl 6 Cl 6 Cl 1 Fe

Practice 2 1 HgO Hg + O2 2 1 2 3 3 Al + MnO Al2O3 + Mn 2 Al, 3 Mn, 3 O Br2+ NaI NaBr + I2 2 Br, 2 Na, 2 I 2 Br, 2 Na, 2 I Do these on own 2 1 HgO Hg + O2 2 2 Hg, 2 O 2 Hg, 2 O

Coefficients Must Be in Lowest WHOLE Number! 2 4 2 1 2 21/2 5 1 C2H2 + O2 CO2 + H2O What number can you multiply 21/2 by to get the smallest whole number? 2! So, multiply the whole equation by 2 to get a properly balanced equation. 4 C, 4 H, 10 O 4 C, 4 H, 10 O

You try. Multiply by 2! 8 C, 2O H, 26 O 8 C, 2O H, 26 O 4 1 2 13 8 61/2 10 C4H10 + O2 CO2 + H2O 5 Multiply by 2! 8 C, 2O H, 26 O 8 C, 2O H, 26 O

Classification of Chemical Reactions 1. Synthesis 2. Decomposition 3. Single Replacement 4. Double Replacement 5. Combustion (burning)

A B AB Synthesis Examples: 1 Cu + O2 2 CuO 1 H2CO3 CO2 + H2O Two reactants combine to form a single product (compound). A B AB One Product Examples: 1 2 Cu + O2 CuO 1 H2CO3 CO2 + H2O

AB A B Decomposition Examples: 2 3 KClO3 KCl + O2 1 2 H2O2 H2O + O2 One reactant breaks down to form two or more products. AB A B One Reactant Examples: 2 3 KClO3 KCl + O2 1 2 H2O2 H2O + O2

A BC AC B Single Replacement Examples: 2 1 Mg + HCl MgCl2 + H2 2 1 One element replaces another from a compound A BC AC B Examples: 2 1 Mg + HCl MgCl2 + H2 2 1 Cl2 + KI KCl + I2

Double Replacement (ionic) Ions in a solution combine to form a product that leaves the scene of the reaction AB CD AD CB Example: AgNO3 (aq) + NaCl (aq) AgCl (s) + NaNO3 (aq)

More on Double Replacement Precipitate (s), gas (g) or water (H2O) will form AgNO3 (aq) + NaCl (aq) AgCl (s) + NaNO3 (aq) Actual reaction: AgCl Ag+1 + Cl-1 Don’t dwell (do it in depth later) Spectator Ions: Na+1 & NO3-1

What happens when you put AgNO3 (aq) + NaCl(aq) AgCl(s) + NaNO3(aq) What happens when you put AgNO3 and NaCl in water?

NaCl AgNO3

NaCl AgNO3

AgNO3 NaCl

AgNO3 NaCl

AgNO3 NaCl

AgNO3 NaCl

AgNO3 NaCl

Ag NO3 Na Cl

Ag+ NO3- Na+ Cl-

Ag+ NO3- Na+ Cl-

Ag+ NO3- Cl- Na+

NO3- Ag+ Na+ Cl-

NO3- Na+ Ag+ Cl-

NO3- Na+ Ag+ Cl-

NO3- Na+ Cl- Ag+

Na+ NO3- Cl- Ag+

Na+ NO3- Cl- Ag+

Na+ NO3- Ag+ Cl-

Na+ NO3- Ag+ Cl-

Na+ NO3- Ag+ Cl-

Na+ NO3- Ag+ Cl-

NO3- Na+ AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl(s) precipitate AgCl

Na+ NO3- AgCl(s) precipitate AgCl

Na+ NO3- AgCl

NO3- Na+ AgCl

NO3- Na+ AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

Na+ NO3- AgCl

AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 AgNO3 AgNO3 NaCl

AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 AgNO3 AgNO3 NaCl

AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 AgNO3 AgNO3 NaCl

AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 NaCl NaCl NaCl AgNO3 AgNO3 AgNO3 AgNO3 NaCl Ag+ Na+ NO3- Cl-

AgNO3 NaCl NaCl NaCl AgNO3 NaCl AgNO3 Ag+ Na+ NO3- Cl- Ag+ Cl- NO3- Na+ Na+ Ag+ NO3- Cl- AgCl

Ag+ Na+ NO3- Cl- Cl- Cl- Na+ Ag+ NO3- NO3- Ag+ Na+ NO3- Ag+ Cl- Na+ NO3- Cl- NO3- Na+ Cl- Na+ Ag+ Ag+ Cl- Ag+ Cl- Cl- Ag+ Ag+ AgCl AgCl AgCl

Ag+ NO3- Cl- Ag+ NO3- Na+ Ag+ Cl- NO3- Na+ NO3- Ag+ Cl- NO3- NO3- Na+ Cl- Na+ Na+ Cl- Ag+ Ag+ Na+ NO3- Cl- NO3- Na+ Na+ Na+ Cl- Ag+ AgCl AgCl AgCl AgCl

Ag+ NO3- Cl- NO3- Na+ NO3- NO3- Na+ Ag+ NO3- NO3- Cl- Na+ Na+ Na+ Cl- Ag+ Ag+ NO3- Cl- Na+ Na+ Na+ NO3- Na+

NO3- NO3- Na+ NO3- NO3- Na+ NO3- NO3- Na+ Na+ Na+ Cl- Ag+ Ag+ NO3- Cl- Na+ Na+ Na+ NO3- Na+

NO3- NO3- Na+ NO3- NO3- Na+ NO3- NO3- Na+ Na+ Na+ Cl- Ag+ Ag+ NO3- Cl- Na+ Na+ Na+ NO3- Na+

NO3- Na+ Na+ NO3- Na+ NO3- NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ NO3- Na+ Na+

NO3- Na+ NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ AgCl(s)

NO3- Na+ Na+ NO3- Na+ NO3- NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ NO3- AgCl(s)

NO3- Na+ NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ Na+ Na+ NO3- NO3- Na+ AgCl(s)

Combustion (burning) Produces light and heat CxHy+ O2 CO2 + H2O Balance C 1st, then H, then O (because it splits up) 3 1 C3H8 + O2 5 CO2 + H2O 4 1 2 C2H2+ O2 2 4 CO2 + H2O 2 1 2.5 5

Classification of Equations SYNTHESIS AB A B Ca S CaS DECOMPOSITION AB A B 2HgO 2Hg O2

Classification of Equations SINGLE REPLACEMENT AB C A BC 2KCl Br2 Cl2 2KBr DOUBLE REPLACEMENT AB CD AD CB CaSO4 BaCl2 CaCl2 BaSO4

Putting it all together 1. Assign the charges. 2. Write the correct formulas. 3. Balance the equation. 4. Identify the type of reaction. BEFORE this they balance equation sheet (see star) then go back and ID type of equation Iron (II) sulfide + Hydrochloric acid Iron (II) chloride + Hydrogen sulfide

1. Write the ions and element symbols Iron (II) sulfide + Hydrochloric acid Iron (II) chloride + Hydrogen sulfide Fe+2S-2 + HCl Fe+2Cl-1 + H+1S-2

2. Rewrite the correct formula. Fe+2S-2 + HCl Fe+2Cl-1 + H+1S-2 FeS + HCl FeCl2 + H2S

4. Identify the type of reaction. 3. Balance the equation. 1 FeS + HCl FeCl2 + H2S 2 1 1 4. Identify the type of reaction. Insist on them writing oxidation states BEFORE formula. Double Replacement!

Try this one. Ca0 + HCl Ca+2Cl-1 + H20 1 + HCl Ca CaCl2 + H2 2 1 1 1. Assign the charges. 2. Rewrite the correct formulas. 3. Balance the equation. 4. Identify the type of reaction. Calcium + Hydrochloric acid Calcium chloride+ Hydrogen Ca0 + HCl Ca+2Cl-1 + H20 1 + HCl Ca CaCl2 + H2 2 1 1 Single Replacement!

Try this one. Zn+2 (OH)-1 Zn+2O-2 + H2O Zn(OH)2 ZnO + H2O 1 1 1 1. Assign the charges. 2. Rewrite the correct formulas. 3. Balance the equation. 4. Identify the type of reaction. Zinc hydroxide Zinc oxide+ water Zn+2 (OH)-1 Zn+2O-2 + H2O Zn(OH)2 ZnO + H2O 1 1 1 Maybe stop here and go on own with worksheet (depend on how they handle it). Decomposition!

Try this one. N20 + O20 N+2O-2 1 N2 + O2 NO 1 2 Synthesis! Nitrogen 1. Assign the charges. 2. Rewrite the correct formulas. 3. Balance the equation. 4. Identify the type of reaction. Nitrogen Nitrogen oxide + Oxygen N20 + O20 N+2O-2 1 N2 + O2 NO 1 2 Synthesis!

Activity Series of the Elements: Table L Li Rb K Ba Sr Ca Na Mg Al Mn Zn Cr Fe Cd Co Ni Sn Pb H2 Sb Bi Cu Hg Ag Pt Au Nonmetals F2 Cl2 Br2 I2 Replaces H from acids Replaces H from water Most Active Most Active Least Active Least Active Metals replace metals or H Nonmetals replace nonmetals *REPLACE FROM OWN COLUMN

Making Predictions: Single Replacement Rxn 1. Assign the charges and predict products. 2. Rewrite correct formulas. 3. Use activity series to tell if rxn occurs and why. 4. Balance equation. Pepsi commercial Aluminum + Nickel (II) chloride ?

1. Assign the charges and predict products. Aluminum + Nickel (II) chloride ? Al0 + Ni+2Cl-1 Al+3Cl-1 + Ni0 2. Rewrite correct formulas. Al + NiCl2 AlCl3 + Ni

3. Use the activity series to tell if the rxn occurs and why. Yes, Al is more active than Ni. 2 Al + NiCl2 3 2 AlCl3 + Ni 3 4. Balance equation.

Now try this one. Ca0 + Co+3(NO3)-1 Ca+2(NO3)-1 + Co0 3 3 Ca(NO3)2 Ca 1. Assign the charges (for compounds) and predict products. 2. Rewrite correct formulas. 3. Use activity series to tell if rxn occurs and why. 4. Balance equation. Calcium + Cobalt (III) nitrate ? Ca0 + Co+3(NO3)-1 Ca+2(NO3)-1 + Co0 3 3 Ca(NO3)2 Ca + Co 2 + Co(NO3)3 2 Yes, Ca is more active than Co.

Now try this one. Br20 + Rb+1I-1 Rb+1Br-1 + I20 2 1 2 RbBr + I2 1 Br2 1. Assign the charges (for compounds) and predict products. 2. Rewrite correct formulas. 3. Use activity series to tell if rxn occurs and why. 4. Balance equation. Bromine + Rubidium Iodide ? Br20 + Rb+1I-1 Rb+1Br-1 + I20 2 1 2 RbBr + I2 1 Br2 + RbI Yes, Br is more active than I.

Making Predictions: Double Replacement Rxn Double Replacements will only complete when one or more of these events occur: 1. Water forms (H2O) 2. A gas forms (g) 3. A precipitate (s) forms Do “Chapter 9 Double Replacement Reactions” first two together, rest on own.

Let’s try a couple Does the reaction occur? Does the reaction occur? Ba(OH)2 (aq) + H2SO4(aq) BaSO4(aq) + H2O(l) Does the reaction occur? YES; water is formed. What are the spectator ions? (The ions not involved in forming water, gas, or precipitate) Ba+2 & SO4-2 Ca3(PO4)2(aq) + NaNO3(aq) Na3(PO4)2(aq) + CaNO3(aq) Does the reaction occur? No; no water, gas or precipitate is formed.

Potassium chromate + copper(II) hydroxide 1. Assign the charges and predict products. Rewrite correct formulas and look up states of products on Table C. K+1 (CrO4)-2 + Cu+2(OH)-1 Cu+2(CrO4)-2 + K+1(OH)-1 K2 (CrO4) + Cu(OH)2 Cu(CrO4) (s) + K(OH) (aq) insoluble on Table C soluble on Table C

Does a precipitate (s) form? 1 2 Potassium chromate + copper(II) hydroxide 3. Balance equation. 4. Does reaction occur? Does water form? Does a gas (g) form? Does a precipitate (s) form? 1 2 K2CrO4 + Cu(OH)2 CuCrO4 (s) + KOH (aq) NO Do “Double Replacement Reactions” predicting Then single and double replacement reactions predicting NO YES! THE RXN OCCURS!