chemical symbols, formulas & equations. chemical symbols a symbol represents one element (1-3...

Chemical Symbols, Formulas & Equations

Chemical SymbolsA symbol represents

one element (1-3 letters)

Symbol Writing Rules1st letter is always

capitalized2nd & 3rd letters (if

any) are always lower case

Symbols

OOxygen

SnTin

UutUnuntriu

m

CoCobalt

element #27bluish metal

COCarbon monoxide

Molecule:( 1 carbon, 1 oxygen)colorless, odorless,

tasteless, deadly gas

Co v CO

IUPAC Naming New ElementsNew elements are being synthesized (made) in the labNames for the element has to wait until the IUPAC naming

committee meetsA temporary name based on the atomic number IN LATIN is

given to the new elementTime to learn some Latin

Rules for naming elements1. Break up the atomic number into digits (#118 becomes 1, 1, 8)2. Replace the digits with the Latin number (1, 1, 8 becomes un un

oct3. Put the Latin numbers together and add “–ium” ending –

ununoctium4. The symbol is the first letter of each of the Latin numbers (follow

the rules) ununoctium - Uuo

• 1 – un• 2 – bi• 3 – tri

• 4 – quad • 5 – pent• 6 – hex

• 7 – sept 0-nil• 8 – oct• 9 – enn

IUPAC SamplesAtomic Number Symbol

113 UutName

ununtrium

234 Btqbitriquadium

506 Pnhpentnilhexium

Chemical FormulasChemical “shorthand” to describe a compoundGives the symbol & number of atoms of each

elementRules for Formulas

1. every Capital letter indicates another element2. a lowered number (called a subscript) after an

element tells you how many atoms of that element are in the compound/molecule (no subscript means 1)

3. A number in front of a FORMULA tells you how many units or molecules of that substance there are (this is called the formula coefficient)

Examples (Formula Rules 1 & 2)

Compound Formula # Atoms of Each Element

Carbon Dioxide CO2 1 -Carbon 2- Oxygens

Sugar C6H12O6 6-Carbons 12 - Hydrogens 6-Oxygens

Copper Sulfate CuSO4 1-Copper 1-Sulfur 4-Oxygens

Baking Soda NaHCO3 1-Sodium 1-Hydrogen 1-Carbon 3-Oxygens

Polyatomic Ions (parts in parentheses)Some combinations of elements bond together and

act like an element – they usually stay togetherExamples:

Phosphate PO4

Hydroxide OHAmmonium NH4

Acetate C2H3O2

Nitrate NO3

Because there is more than one element bonded together, if more than one polyatomic ion is needed youWrap parentheses around the ion in the formulaPut the subscript outside the parentheses

Counting Elements with ()Since the polyatomic ion acts like an

element, its subscript multiplies the number of ions needed

Ex. ClO3 is a poly atomic ion called chlorate so…

Mg(ClO3)2 means we have 1 magnesium and 2 chloratesBut each chlorate is 1-chlorine and 3-oxygensTherefore the subscript outside the ()

multiplies the each of the number of elements inside the parentheses for the total

(ClO3)2 ends up with 2-chlorines (2 *1) and 6-oxygens (2*3)

Counting with Polyatomic Ions Samples

Formula Element Count

Ca3(PO4)2

Al(C2H3O2)3

3-Calcium2-Phosphorous

(2*1)8-Oxygen (2*4)

1-Aluminum6-Carbon (3*2)9-Hydrogen (3*3)6-Oxygen (3*2)

Al

Review Practice

Compound Contents

HgBr2

Be(NO3)2

Al(C2H3O2)3

1-Mercury2-Bromine

1-Beryllium2-Nitrogen (1*2)6-Oxygen (3*2)

1-Aluminum6 Carbon (2*3)9-Hydrogen (3*3)6-Oxygen (2*3)

Example (Formula Rule #3)

C2H6O + 3O2 3H2O + 2CO21- C2H6O molecule is needed (no number means 1)

3- O2 molecules are needed

3- H2O molecules are needed

2- CO2 molecules are needed

2-Carbons6-Hydrogens1-Oxygen

6-Oxygens6-Hydrogens3-Oxygens

2 Carbons4-Oxygens

Coefficient Samples

Formula Contents

4 H2O

2 MgCl2

3 C6H12O6

4*2 = 8 Hydrogen4*1 = 4 Oxygen

2*1 = 2 Magnesium2*2 = 4 Chlorine

3*6 = 18 Carbon3*12 = 36 Hydrogen3*6 = 18 Oxygen

Do # 18, 19, 20 on back page

Review Video

Putting it all togetherSince a coefficient multiplies the number of

compounds thenThe coefficient will also multiply the number

of polyatomic ionsRule: The coefficient AND a subscript

outside the parentheses BOTH multiply the elements inside the parentheses.

Example 3 Ca3(PO4)2

9-Calcium (3*3)6-Phosphorus (3*1*2)24-Oxygen *(3*4*2)

Other Examples

Compound Count

3 (NH4)2SO4

4 Cu(NO3)2

6-Nitrogen (3*1*2)24-Hydrogen

(3*4*2)3-Sulfur (3*1)12-Oxygen (3*4)

4-Copper (4*1)8-Nitrogen (4*1*2)24-Oxygen (4*3*2)

Conservation of MassMatter cannot be created or destroyed (actually

the law states that the total amount of matter + energy in a closed system remains constant but that is a little lofty for what we will be doing)

For Us: In a reaction the total number of elements we start the reaction with must equal the total number of elements we end with.

Example H2 + O2 H2O

Since the totals on each side of the are not equal we need to use coefficients to “balance” the equation

Balancing a Chemical Equation

Samples Samples

S + O2 SO2

1- sulfur2-oxygen

1-sulfur2-oxygen

1-sodium2-oxygen

2-sodium1-oxygen

Na + O2 Na2O

x2

1-sodium2-oxygen

4-sodium2-oxygen

x4

4-sodium2-oxygen

4-sodium2-oxygen

4 Na + O2 2Na2O

Na + O2 2 Na2O

H2 + Cl2 HCl2- hydrogen

2-chlorine1-hydrogen1-chlorine

H2 + Cl2 2HCl

2-silver1-oxygen

1-silver2-oxygen

x2

4-silver2-oxygen

1-silver2-oxygen

2 Ag2O Ag + O2

x2

2- hydrogen2-chlorine

2-hydrogen2-chlorine

Ag2O Ag + O2

2 Ag2O 4Ag + O2

x4


Equation Procedure

H2 + O2 H2O

Count the atoms on each side of the equation ()2-hydrogen

2-oxygen2-hydrogen1-oxygen

need to multiply the oxygen on the right by 2

2-hydrogen2-oxygen

4-hydrogen2-oxygen

4-hydrogen2-oxygen

4-hydrogen2-oxygen

x2

x2

2H2 + O2 2H2O

H2 + O2 2H2O

Select one of the elements that are out of balance and use a coefficient to multiply its compound & recount

Repeat this process until all elements are balanced (numbers of an element are the same on each side)

Change ONLY the COEFFICIENTS, NEVER the SUBSCRIPTS!!

1- carbon4-hydrogen2-oxygen



Samples Samples

CO + O2 CO2

1- carbon3-oxygen (1/2)

1-carbon2-oxygen

2-nitrogen2-hydrogen


N2 + H2 NH3

x2



2 CO + O2 2CO2

N2 + 3H2 2NH3

CH4 + O2 CO2 + H2O1- carbon4-hydrogen2-oxygen

CH4 + O2 CO2 + 2H2O

x2 CH4 + 2O2 CO2 + 2H2O

x2x2x2 just the CO

x3

2-carbon4-oxygen (1/2)

2-carbon4-oxygen




2- hydrogen2-nitrogen1-oxygen

Balancing a Chemical EquationSamples

H2 + NO H2O + N22- hydrogen1-nitrogen1-oxygen

H2 + 2NO H2O + N2

x2

H2 + 2NO 2H2O + N2

x2

x2


2- hydrogen2-nitrogen1-oxygen2-

hydrogen2-nitrogen2-oxygen


2H2 + 2NO 2H2O + N2



chemical symbols, formulas & equations. chemical symbols a symbol represents one element (1-3...

Documents