Unit One

Notes #1 Unit One

• Two Classes of Elements

• Periodic Table Info?

• What Are Stable Elements?

• Oxidation/Reduction

• Oxidation Numbers

• Key Elements and Examples

• Pgs 158-165

Draw a picture of an Atom

For a chemical RXNto occur, two atoms MUST collide. Since the electrons are on the outside, then it is only the electrons that are involved !!!

Electrons are either LOSTOR GAINED

Two Classes of Elements• What are the Two Main Classes of Elements?• Metals and Nonmetals (Stair-Step)

What information doe the Periodic Table give us?

Atomic Number# Protons = # of Electrons

Mass Number = # P + # N

Electron structure

So any Atom as no charge

• The atomic number tells us the number of protons (+ charges) AND the number of electrons (- charges) .

• If you add all the charges up in an atom, they will equal ZERO.

• An ATOM has NO NET Charge !!!

If we start with an Atom…..

• And it gains electrons, what happens to its’ charge?

• It becomes negative• And it loses electrons, what happens to its’

chare? • It becomes positive.

• If an atom becomes + or – we call it an ION

We can only change the # of electrons

• If we were to try to change the number of protons, in the nucleus ….things have a tendency of going BOOM ! That is a nuclear reaction. So most chemical reactions involve the LOSS or GAIN of electrons

• OXIDATION = Loss of electrons

• REDUCTION = Gain of electrons

What Makes Elements Stable? • Eight Electrons…… we will see this often

• Noble Gases (electronically stable)

• He, Ne, Ar, Kr, Xe, and Rn

• Lose or Gain to get 8e-1 (to become stable)

• Do metals Lose or Gain electrons?

• Do nonmetals Lose or Gain electrons?

(Lose)

(Gain)

Oxidation Numbers• All elements Lose or Gain e-1.

• Some have multiple loss or gain possibilities.

Fe+2 Fe+3 S-2 S+4 S+6

Key Elements

• (99%) H+1 H-1

• (99%)O-2 O-1

• (Always) Li+1, Na+1, K+1, Rb+1, Cs+1, Fr+1

• (Always) Be+2, Mg+2, Ca+2, Ba+2, Sr+2, Ra+2

• (Always) Al+3

• (with only a metal) F-1, Cl-1, Br-1, I-1

• (NO3-1) ion is always +5

• (SO4-2) ion is always +6

Example One• Find the oxidation numbers.• Al2S3

• Algebra is useful!

• Al+3 key element• 2(+3) + 3(S)=0• S= -2

2(Al) +3(S)= 0

Example Two• Find the oxidation numbers.• Ca(NO3)2 • Algebra is useful !

• Ca+2 and O-2 key elements• (+2)+2(N)+6(-2)=0• (+2)+2(N)+(-12)=0• 2(N)+(-10)=0• 2(N)=10• N= +5

(Ca)+2(N)+ 06(O)=

Finding Oxidation #’s for Compounds

+1 -2

+1+5 -2HH33POPO44

H2O

HNO3

+1+5 -2

H2SO4

+1 -2+6

Hg2SO4

+6+1 -2

Na2Cr2O7

+1 +6 -2

H2CO3

+1 -2+4

(NH4)2CO3

-3 +1+4 -2

Ca3(AsO4)2

+2 +5 -2

Fe2(SO4)3

+6+3 -2

Ba(ClO4)2

+2 +7 -2

Al2(CO3)3

+3 +4 -2

Now it is time for class work !!!

• A101: paper practice (Work Together)

• It will be due at beginning of class next time

• Ready Set Break !!!

So Let’s Review• When we are assigning oxidation numbers:

If we are dealing with a molecule and there is no charge, the sum of all the oxidation numbers will add to zero.

If we are dealing with a Polyatomic ion, then the sum of all of the oxidation numbers adds up to that charge

+2 +5 -2 +6 -2

Ca3(PO4)2 Cr2O7 -2

CA101 Assigning oxidation #’sTurn on Mac: double click on the MAC folder on the desktop. Open the Redox folder and click on the yellow, red and blue icon.

Choose the top button: finding oxidationNumbers in triatomic compounds.

You will do 15 problems and show all your algebra work on CA101 !!!!!I will show you how today.

If you click on KEY ELEMENTS Your resource paper is online in The program.

Please get A101 and CA 101 Stamped Today !!!

Once you are done we will introFormula Writing

Notes Two Unit One

• Naming Inorganic Salts

• Example One

• Example One Thinking

• Example Two

• Computer Assignment One

Naming Inorganic Salts• TWO parts to the name• 1) Cation• 2) Anion• Cation Examples• Ca+2 • Al+3 • Fe+2 • Na+1

• Anion Examples• Cl-1

• NO3-1

• SO4-2

• N-3

PositiveNegative

Example One• Name the formula Fe2(CrO4)3

• Step #1 Find The + Ion(s).

Iron(II) Fe+2

Iron(III) Fe+3

Example One• Step #2 Find The - Ion(s)

Chromate CrO4-2

Fe2(CrO4)3 Fe+2 Fe+3 CrO4-2Iron(II) ChromateIron(III)

Fe+2 CrO4-2

Iron(II) Chromate

(+2) (-2)Y+ = 0

X=1 Y=1

FeCrO4

X

(+2) (-2)1+ = 01

Fe+3 CrO4-2

Iron(III) Chromate

(+3) (-2)Y+ = 0

X=2 Y=3

X

(+3) (-2)3+ = 02

Fe2(CrO4)3

Example One

Al2(CO3)3 Al+3 CO3-2 CarbonateAluminum

Al+3 CO3-2

Aluminum Carbonate

(+3) (-2)Y+ = 0

X=2 Y=3

X

(+3) (-2)3+ = 02

Al2(CO3)3

Example Two

In class work today:

• Work on A102

• Use you Cation/Anion Sheet

• Remember to fnd the charges of the ions and make sure that they add up to zero to write the formula.

• When you are naming a formula you always write the + ion first then the -ion

CA 102:Writing FormulaCA 103: Naming Compounds

• NAMING IONIC COMPOUNDS LEVELs ONE AND TWO

• Get A102 , CA 102, CA103 all stamped today.

• Now let’s look at some examples at how to write Formulas from a name. You need to have your Cation/Anion sheet

out.

• Homework for tonight, read L101 Electrolysis of water Lab, we will do that next class !!!!

Writing a Formula From a Name

HH33POPO44

LiNOLiNO33Lithium NitrateLithium Nitrate ( )_( )_LiLi+1+1 NONO33

-1-11111

Hydrogen PhosphateHydrogen Phosphate ( )_( )_HH+1+1 POPO44-3-3

1133

CaCa33(AsO(AsO44))22

(NH(NH44))22COCO33Ammonium carbonateAmmonium carbonate ( )_( )_NHNH44

+1+1 COCO33-2-2

1122

Calcium ArsenateCalcium Arsenate ( )_( )_CaCa+2+2 AsOAsO44-3-3

2233

HgHg22SOSO44

Fe(IOFe(IO44))33Iron(III) periodateIron(III) periodate ( )_( )_FeFe+3+3 IOIO44

-1-13311

Mercury(I) SulfateMercury(I) Sulfate ( )_( )_HgHg22+2+2 SOSO44

-2-22222

NaNa22CrCr22OO77

Ba(ClOBa(ClO44))22Barium PerchlorateBarium Perchlorate ( )_( )_BaBa+2+2 ClOClO44

-1-12211

Sodium DichromateSodium Dichromate ( )_( )_NaNa+1+1 CrCr22OO77-2-2

1122

Pb(SOPb(SO44))22Lead(IV) SulfateLead(IV) Sulfate ( )_( )_PbPb+4+4 SOSO44

-2-24422

(Cation+?)X(Anion-?)Y(+?) (-?)Y+ = 0X

Lowest Whole Number Ratio

If X or Y is 2 or greater...

and the ion is polyatomic.

BaBa+2 +2 CrCr22OO77-2 -2 HgHg22

+2 +2 PbPb+4+4

Notes Three Unit One

• Standard Amounts

• One Gopher

• One Mole

• Formula mass

• Percent Composition

• Empirical Formula

Standard Amounts• How many dollars is…• A) 120 pennies?• 1.2 dollars• B) 2 quarters?• 0.5 dollars• C) 15 nickels?• 0.75 dollars• How many dozens is…• D) 48 eggs?• 4 dozen• E)18 apple fritters• 1.5 dozen

One Dozen• You KNOW it equals 12

items

• What if I asked you to

• Go into the lab and get

• 12 Carbon atoms?

One Mole• One mole is 6.022x10+23 items.• Each element on the period table has

a mass per mole.

NOC

14.0g16.0g12.0g

6.022x10+23atoms6.022x10+23atoms6.022x10+23atoms

N

O

C

7.0g

4.0g

18.0g

=0.50m

=0.25m

=1.50m

• How many moles are in each?

=3.01x10+23atoms

=1.51x10+23atoms

=9.03x10+23atoms

÷14.0g/m

÷16.0g/m

÷12.0g/m

• How many atoms are in each?

x6.022x10+23atoms/m

x6.022x10+23atoms/m

x6.022x10+23atoms/m

Calculations Bases on Chemical Formulas

•Formula mass (Molecular Mass or Gram-Formula Mass)•Empirical Formula•Percent Composition

Rounding Atomic Mass

CFeO

12.01155.84715.9994

BiKAu

208.98083739.0983196.96654

OsMgNa

190.2324.305022.98968

12.055.816.0209.039.1197.0190.224.323.0

Formula Mass Example OneCalculate the formula mass for 1 mole of C6H12O6.

CHO

6 x12 x6 x

12.0 = 1.0 =16.0 =

72.012.096.0

180.0g/mol

E # Mass

How many molecules of C6H12O6 is 180.0g/mol?

6.022x10+23 molecules

12.0111.007915.9994

Empirical Formula

• By definition, it is the lowest WHOLE number ratio of elements in a compound.

• It may or may not be the actual MOLECULAR FORMULA.

• But is does so the whole number ratio of elements in a compound.

• HO = empirical formula of Hydrogen Peroxide but H2O2 is the molecular Formula

Empirical Formula Example One

3) Write the formula

What is the empirical (simplest) formula containing 36.8% N, 63.2% O?

X by 2 to get whole numbers

1) Calculate moles of each element.

NO

36.8 g ÷63.2 g ÷

14.0 =16.0 =

2.63 mol N 3.95 mol O

E Q Mass

2) Calculate the lowest ratio. (divide by small moles)

NO

2.63 mol N ÷3.95 mol O ÷

2.63 mol =2.63 mol =

1.00 1.50

E Moles Lowest Ratio

N2O3

14.006715.9994

Mass

Percent Composition Example OneCalculate the percentage composition of H2O.

HO

2 x1 x

1.0 =16.0 =

2.0 16.018.0g/mol

E # Mass

2) Divide each contribution by the total mass.

3) Add the percentages to check work.

1)Calculate the formula mass for 1 mole of H2O

HO

2.0 ÷16.0 ÷

18.0 =18.0 =

0.11 0.889

11% 88.9%100.%

1.007915.9994

( x 100) = 11%( x 100) = 88.9% Answer

Empirical Formula Example Two

3) Write the formula

What is the empirical (simplest) formula containing 69.58% Ba, 6.090% C, 24.32% O?

X by 1 to get whole numbers

1) Calculate moles of each element.

BaC

69.58 g ÷6.090 g ÷

137.33 =12.01 =

0.50666 mol Ba 0.50708 mol C

E Q Mass

2) Calculate the lowest ratio.

BaC

0.50666 mol ÷0.50708 mol ÷

0.50666 mol =0.50666 mol =

1.000 1.001

E Moles Lowest Ratio

BaCO3

O 24.32 g ÷ 16.00 = 1.520 mol O

O 1.520 mol ÷ 0.50666 mol = 3.00

Mass

Percent Composition Example TwoCalculate the percentage composition of Fe(ClO4)3.

ClO

3 x12 x

35.5 =16.0 =

106.5 192.0

354.3g/mol

E # Mass

2) Divide the each contribution by the total mass.

3) Add the percentages to check work.

1)Calculate the formula mass for 1 mole of Fe(ClO4)3.

ClO

106.5 ÷192.0 ÷

354.3 =354.3 =

0.30060.5419

30.1 % 54.2 %100.1%

Fe 1 x 55.8 = 55.8

Fe 55.8 ÷ 354.3 = 0.1575

15.8 %

55.84735.45315.9994

( x 100) = 15.8%( x 100) = 30.06%( x 100) = 54.19%

Answer

Formula Mass Example ThreeCalculate the formula mass for 1 mole of Al2O3

AlO

2 x3 x

27.0 =16.0 =

54.0 48.0102.0g/mol

E # Mass

How many molecules of Al2O3 is102.0g/mol?

6.022x10+23 molecules

26.9815415.9994

Formula Mass Example Two

Calculate the formula mass for 1 mole of CaCO3.

CaCO

1 x1 x3 x

40.1 =12.0 =16.0 =

40.112.0

48.0100.1g/mol

E # Mass

How many molecules of CaCO3 is100.1g/mol?

6.022x10+23 molecules

40.07812.01115.9994