Do Now – 3/4/10Do Now – 3/4/10

Balance the following equation:Balance the following equation:

__H__H22 + __O + __O22 __H __H22OO

Get your homework out so I can check Get your homework out so I can check it while I am checking the Do Nowsit while I am checking the Do Nows

Setup Cornell Notes: “Balancing Setup Cornell Notes: “Balancing Equations”Equations”

22 11 22

Today 3/4/10Today 3/4/10

Do Now/Check HWDo Now/Check HW

Cornell Notes – Balancing EquationsCornell Notes – Balancing Equations

Practice Balancing EquationsPractice Balancing Equations

Work on FoldersWork on Folders

Balancing EquationsBalancing Equations

ObjectivesObjectivesBy the end of the period, you should By the end of the period, you should

be able to. . .be able to. . . Demonstrate a comprehension of Demonstrate a comprehension of

what a chemical equation is, in what a chemical equation is, in relating equations to food recipesrelating equations to food recipes

Describe the difference between Describe the difference between ReactantsReactants and and ProductsProducts

Balance equations on your ownBalance equations on your own

How are these similar, how are How are these similar, how are they different? they different?

__ P4 + __ O2 __ P4 + __ O2 __ P2O5 __ P2O5

4 cups of Corn meal + 1 cup vegatable oil + 1 teaspoon 4 cups of Corn meal + 1 cup vegatable oil + 1 teaspoon flavoring flavoring Flaming hot cheetos Flaming hot cheetos

Write the above and your answer to the right, be prepared to Write the above and your answer to the right, be prepared to share your responses (2 minutes) 2 similarities, 2 share your responses (2 minutes) 2 similarities, 2 differncesdiffernces

NO TALKING YET!!NO TALKING YET!!

2 SIDES to EQUATIONS2 SIDES to EQUATIONS

ReactantsReactants On the left sideOn the left side The things that The things that

REACT!!REACT!!

Examples:Examples:

2H2 + O2 2H2 + O2

2 cups flour + 1 tsp salt 2 cups flour + 1 tsp salt + water+ water

ProductsProducts On the Right sideOn the Right side The finished productThe finished product

Examples:Examples:

2H2O2H2O

Pizza DoughPizza Dough

Why do equations need to Why do equations need to be balanced?be balanced?

Law of Conservation Law of Conservation of Matter:of Matter: matter can be matter can be

neither created nor neither created nor destroyed.destroyed.

Reactants MUST = Reactants MUST = ProductsProducts

Can’t create Can’t create something out of something out of nothingnothing

Balancing Equations: Balancing Equations: RulesRules

1.The number of atoms 1.The number of atoms of each type of of each type of element must be the element must be the same on each side of same on each side of an equation.an equation.

- 2 Hydrogens on left - 2 Hydrogens on left side, 2 Hydrogens on side, 2 Hydrogens on rightright

Balancing Equations: Balancing Equations: RulesRules

2. You can change the 2. You can change the large number in front large number in front of each molecule of each molecule (Coeficient), but not (Coeficient), but not the small numberthe small number

22HH22 + O + O22 2 2 HH22OO

Balancing Equations: Balancing Equations: RulesRules

3. The large number 3. The large number infront, must be infront, must be distributed to distributed to whatever it is infront whatever it is infront ofof

2 2 HH22OO

H = 4H = 4

O = 2O = 2

Balancing Equations: Balancing Equations: RulesRules

4.4. Reduce to lowest termsReduce to lowest terms

22 N2 + N2 +66 H2 H244 NH3 NH3

These can be divided by 2, These can be divided by 2, so. . . 2/2=1, 6/2=3, so. . . 2/2=1, 6/2=3, 4/2=24/2=2

11 N2 + N2 +33 H2 H222 NH3 NH3

Balancing Equations: TipsBalancing Equations: Tips1.1. Always balance Always balance

Oxygen and Hydrogen Oxygen and Hydrogen last (think santa: ho last (think santa: ho ho ho)ho ho)

2.2. If you get stuck. . .If you get stuck. . .1.1. Put a 1 infront of the most Put a 1 infront of the most

intimdating looking molcule intimdating looking molcule and attempt to balance.and attempt to balance.

2.2. If that doesn’t work, put a If that doesn’t work, put a 2 in front, etc.2 in front, etc.

How to balanceHow to balance

Full Proof MethodFull Proof Method1.1. Brackets-list what Brackets-list what

you haveyou have

If its by itself, gets If its by itself, gets own bracketown bracket

2. Multiply2. Multiply

3. Count ‘em3. Count ‘em

4.4. Check your workCheck your work

5.5. Write in your large Write in your large numbers numbers (Coefficients)(Coefficients)

Short cutShort cut Don’t worry Don’t worry

about this yetabout this yet

Complete the Following on your Complete the Following on your OwnOwn

1. 1. __Fe + __H__Fe + __H22S0S04 4 ____FeFe22(SO(SO44))3 3 + + __H__H2 2

2. 2. __C__C22HH6 6 + __O+ __O2 2 ____HH22O O + __CO+ __CO2 2

3. 3. ____KOH +KOH + __ __HH33POPO4 4 ____KK33POPO4 4 + + ____HH22O O 4. 4. __SnO__SnO2 2 + + __H__H2 2 ____Sn + __HSn + __H22O O 5. 5. __NH__NH3 3 + __O+ __O2 2 ____NO NO + __H+ __H22O O

Folders:Folders:

See exampleSee example Front of folder: Cover pageFront of folder: Cover page Title: Chapter 9: Title: Chapter 9:

Balancing EquationsBalancing Equations

Hydrogen and oxygen are diatomic Hydrogen and oxygen are diatomic elements – they don’t like to be alone.elements – they don’t like to be alone.

Their subscripts cannot be changed.Their subscripts cannot be changed. The subscripts on water cannot be The subscripts on water cannot be

changed.changed.

Hydrogen + oxygen Hydrogen + oxygen waterwater

HH22 + O + O22 H H22OO

Balancing EquationBalancing Equation

Count the atoms on each side.Count the atoms on each side. Reactant side: 2 atoms H and 2 atoms OReactant side: 2 atoms H and 2 atoms O Product side: 2 atoms H and 1 atom OProduct side: 2 atoms H and 1 atom O

HH2 2 + O+ O22 H H22OO

Balancing EquationsBalancing Equations HH2 2 + O+ O22 H H22OO

If the subscripts cannot be altered, If the subscripts cannot be altered, how can the atoms be made how can the atoms be made equal?equal?

Adjust the number of molecules by Adjust the number of molecules by changing the changing the coefficientscoefficients. .

Balancing EquationsBalancing Equations

Reactants: 2 atoms of H and 2 Reactants: 2 atoms of H and 2 atoms of Oatoms of O

Products: 4 atoms of H and 2 Products: 4 atoms of H and 2 atoms of Oatoms of O

H is no longer balanced!H is no longer balanced!

HH22 + O + O22 22HH22OO

Balancing EquationsBalancing Equations

Reactant side: 4 atoms of H and 2 atoms of Reactant side: 4 atoms of H and 2 atoms of OO

Product side: 4 atoms of H and 2 atoms of OProduct side: 4 atoms of H and 2 atoms of O It’s Balanced!It’s Balanced!

22HH22 + O + O22 22HH22OO

Balancing EquationsBalancing Equations

Count atoms.Count atoms. Reactants: 2 atoms N and 2 atoms HReactants: 2 atoms N and 2 atoms H Products: 1 atom N and 3 atoms of NHProducts: 1 atom N and 3 atoms of NH33

NN22 + H + H22 NH NH33

Nitrogen + hydrogen ammoniaNitrogen + hydrogen ammonia

Balancing EquationsBalancing Equations Nothing is balanced.Nothing is balanced. Balance the nitrogen first by placing Balance the nitrogen first by placing

a coefficient of 2 in front of the NHa coefficient of 2 in front of the NH33..

NN22 + H + H22 22NHNH33

Balancing EquationsBalancing Equations Hydrogen is not balanced.Hydrogen is not balanced. Place a 3 in front of HPlace a 3 in front of H2.2.

Reactant side: 2 atoms N, 6 atoms HReactant side: 2 atoms N, 6 atoms H Product side: 2 atoms N, 6 atoms HProduct side: 2 atoms N, 6 atoms H

NN22 + + 33HH22 22NHNH33

Balancing EquationsBalancing Equations

Count atoms.Count atoms. Reactants: Ca – 3 atoms, P – 2 Reactants: Ca – 3 atoms, P – 2

atoms, O – 8 atoms; H – atoms, S – atoms, O – 8 atoms; H – atoms, S – 1 atom, O – 4 atoms1 atom, O – 4 atoms

CaCa33(PO(PO44))22 + H + H22SOSO44 CaSOCaSO44 + H + H33POPO44

Balancing EquationsBalancing Equations Side note on CaSide note on Ca33(PO(PO44))22

The subscript after the The subscript after the phosphate indicates two phosphate indicates two phosphate groups.phosphate groups.

This means two POThis means two PO443-3- groups with groups with

two P and eight O atoms.two P and eight O atoms.

Balancing EquationsBalancing Equations

CaCa33(PO(PO44))22 + H + H22SOSO44 CaSOCaSO4 4 + H + H33POPO44

Count atoms in the product.Count atoms in the product. Ca atoms – 1, S atom – 1, O atoms – Ca atoms – 1, S atom – 1, O atoms –

4; H atoms – 3, P atom – 1, O atoms - 4; H atoms – 3, P atom – 1, O atoms - 44

Balancing EquationsBalancing Equations In this equation, the ion groups do In this equation, the ion groups do

not break up.not break up. Instead of counting individual atoms, Instead of counting individual atoms,

ion groups may be counted.ion groups may be counted.

CaCa33(PO(PO44))22 + H + H22SOSO44 CaSOCaSO4 4 + H + H33POPO44

Balancing EquationsBalancing Equations

CaCa33(PO(PO44))22 + H + H22SOSO44 CaSOCaSO4 4 + H + H33POPO44

Reactants: CaReactants: Ca2+2+ – 3, PO – 3, PO443- 3- - 2, H- 2, H++ – 2, – 2,

SOSO442+ 2+ - 1- 1

Products: CaProducts: Ca2+2+ - 1, SO - 1, SO442- 2- - 1, H- 1, H++ - 3, PO - 3, PO44

3-3- - 1- 1

Balancing EquationsBalancing Equations Balance the metal first by placing a Balance the metal first by placing a

coefficient of 3 in front of CaSOcoefficient of 3 in front of CaSO44.. Products: Ca – 3 atoms, SOProducts: Ca – 3 atoms, SO44

2-2- - 3 - 3 groupsgroups

CaCa33(PO(PO44))22 + H + H22SOSO44 33CaSOCaSO4 4 + H + H33POPO44

Balancing EquationsBalancing Equations Three sulfate groups are needed on the reactant Three sulfate groups are needed on the reactant

side so place a coefficient of 3 in front of Hside so place a coefficient of 3 in front of H22SOSO44.. 3H3H22SOSO44 gives 6 H gives 6 H++ and 3 SO and 3 SO44

2-2-.. Neither phosphate nor calcium is balanced.Neither phosphate nor calcium is balanced.

CaCa33(PO(PO44))22 + + 33HH22SOSO44 33CaSOCaSO4 4 + H + H33POPO44

Balancing EquationsBalancing Equations A coefficient of 2 placed in front A coefficient of 2 placed in front

of Hof H33POPO44 which balances both which balances both hydrogen and phosphate.hydrogen and phosphate.

CaCa33(PO(PO44))22 + + 33HH22SOSO44 33CaSOCaSO4 4 + + 22HH33POPO44

Balancing EquationsBalancing Equations

The sulfate group breaks up. Each atom The sulfate group breaks up. Each atom must be counted individually. Ugh!must be counted individually. Ugh!

Reactants: Cu – 1, H – 2, S – 1, O – 4Reactants: Cu – 1, H – 2, S – 1, O – 4 Products: Cu – 1, S – 1, O - 4, H – 2, O – Products: Cu – 1, S – 1, O - 4, H – 2, O –

1, S – 1, O - 21, S – 1, O - 2

Cu + HCu + H22SOSO44

CuSOCuSO4 4 + H + H22O + SOO + SO22

Balancing EquationsBalancing Equations Sulfur is not balanced.Sulfur is not balanced. Place a two in front of sulfuric acid.Place a two in front of sulfuric acid. Count atoms: 2 HCount atoms: 2 H22SOSO44 H – 4, S – 2, O - H – 4, S – 2, O -

88

Cu + Cu + 22HH22SOSO44

CuSOCuSO44 + H + H22O + SOO + SO22

Balancing EquationsBalancing Equations Hydrogen needs to be balanced Hydrogen needs to be balanced

so place a 2 in front of the Hso place a 2 in front of the H22O. O. Count the number of atoms.Count the number of atoms.

Cu + Cu + 22HH22SOSO44

CuSOCuSO44 + + 22HH22O + SOO + SO22

Balancing EquationsBalancing Equations Reactants: Cu – 1, H – 4, S – 2, O – 8Reactants: Cu – 1, H – 4, S – 2, O – 8 Products: Cu – 1, S – 1, O – 4, H – 4, Products: Cu – 1, S – 1, O – 4, H – 4,

O – 2, S – 1, O – 2 = Cu – 1, S – 2, H O – 2, S – 1, O – 2 = Cu – 1, S – 2, H – 4, O – 8– 4, O – 8

It’s balanced!It’s balanced!

Cu + Cu + 22HH22SOSO44

CuSOCuSO44 + + 22HH22O + SOO + SO22

Balancing EquationsBalancing Equations Balancing hints:Balancing hints:

Balance the metals first.Balance the metals first. Balance the ion groups next.Balance the ion groups next. Balance the other atoms.Balance the other atoms. Save the non ion group oxygen Save the non ion group oxygen

and hydrogen until the end.and hydrogen until the end.

Balancing EquationsBalancing Equations This method of This method of

balancing balancing equations is equations is the inspection the inspection method.method.

The method is The method is trial and error.trial and error.

Practice.Practice.

Writing and NamingWriting and Naming

Write the corresponding formula Write the corresponding formula equation and then balance the equation and then balance the equation.equation.

Nickel + hydrochloric acid Nickel + hydrochloric acid

Nickel(II) chloride + hydrogenNickel(II) chloride + hydrogen

Writing and NamingWriting and Naming Write each formula independently.Write each formula independently. Ignore the rest of the equation.Ignore the rest of the equation. Balance the equation after writing Balance the equation after writing

the formulasthe formulas..

Ni + HCl NiClNi + HCl NiCl22 + H + H22

Ni + Ni + 22HCl NiClHCl NiCl22 + H + H22

Writing and NamingWriting and Naming Remember the diatomic elements: Remember the diatomic elements:

HH22, N, N22, O, O22, F, F22, Cl, Cl22, Br, Br22, and I, and I2.2.

Writing and NamingWriting and Naming

Balance the formula equation.Balance the formula equation. Write the word equation.Write the word equation.

Cu + HCu + H22SOSO44

CuSOCuSO44 + H + H22O + SOO + SO22

Writing and NamingWriting and Naming Cu + Cu + 22HH22SOSO44

CuSOCuSO44 + + 22HH22O + SOO + SO22

Write the names:Write the names: Cu by itself is just Cu by itself is just coppercopper. Copper(I) . Copper(I)

or copper(II) would be incorrect.or copper(II) would be incorrect. HH22SOSO44 should be named as an acid. should be named as an acid. Sulfuric acidSulfuric acid

Writing and NamingWriting and Naming CuSOCuSO44 has a SO has a SO44

2-2- group so Cu must group so Cu must be 2+. Some metals must have be 2+. Some metals must have Roman Numerals. Roman Numerals. Copper(II) Copper(II) sulfatesulfate

HH22O is known as O is known as waterwater.. SOSO22 is a nonmetal compound. Its is a nonmetal compound. Its

name is either name is either sulfur dioxidesulfur dioxide or or sulfur(IV) oxidesulfur(IV) oxide..

Writing and NamingWriting and Naming

Copper + sulfuric acid Copper + sulfuric acid Copper(II) sulfate + water + Copper(II) sulfate + water +

sulfur dioxidesulfur dioxide

Cu + Cu + 22HH22SOSO44

CuSOCuSO44 + + 22HH22O + SOO + SO22