chapter 7- chemical formulas and chemical compounds

Chapter 7- Chemical Formulas and Chemical

Compounds

Ban Dihydrogen Monoxide! Colorless, odorless, tasteless Kills uncounted thousands of people every year. Most deaths caused by accidental inhalation Prolonged exposure to its solid form causes severe

tissue damage. Symptoms of ingestion can include

excessive sweating and urination, a bloated feeling, nausea, vomiting body electrolyte imbalance.

For those who have become dependent, withdrawal means certain death.

Ban Dihydrogen Monoxide! Also known as hydroxl acid Major component of acid rain Contributes to the "greenhouse effect." May cause severe burns. Contributes to the erosion of our natural landscape. Accelerates corrosion and rusting of many metals. May cause electrical failures and decreased

effectiveness of automobile brakes. Been found in excised tumors of terminal cancer

patients. Is now an ingredient in most foods and beverages

Ban Dihydrogen Monoxide!Based on the evidence presented in the

previous two slides, do you support the banning of dihydrogen monoxide?

Write at least two sentences stating your reasoning.

Please sign the petition!

What is Dihydrogen Monoxide?

Chemical Formulas Indicate the relative number of atoms or

ions of each kind in a chemical compound

C8H18

MgCl2

Ca(OH)2

8 C atoms 18 H atoms

2 OH- ions

2 Cl- ions

1 Ca2+ ion

1 Mg2+ ion

Monatomic Ions Ions formed from a single atomUsually have noble gas configurationsThat’s how we determine its chargeExample:

Li: 1s22s1

Li+: 1s2 or [He]Table on p.221 on monatomic ions

Naming Monatomic CationsUse the element’s name!Yes, it’s that simple!Example:

Cs+ = cesiumAl3+ = aluminum

Naming Monatomic AnionsDrop the ending of the element’s nameAdd the ending –ideExamples:

Cl- = chlorideN3- = nitride

Naming Monatomic IonsK+

S2-

Rb+

O2-

I-

Ba2+

Cu+

potassiumsulfiderubidiumoxide iodidebariumcopper

Binary Ionic CompoundsCompounds composed of two ionsTotal numbers of positive charges and

negative charges must be equalExamples:

NaClKBrCaF2

Writing Binary Ionic CompoundsWrite the symbols for the ions side by

side. Write the cation first.Al3+ O2-

Cross over the charges to use as the subscript for the other ion.

Al3+ O2-

Al2 O3

Writing Binary Ionic CompoundsCheck the subscripts and divide them to

give the smallest whole number ratio of ions.

Al2O3

Write the formula!Al2O3

Writing Binary Ionic CompoundsZinc iodideBarium fluorideLithium oxideCalcium oxideMagnesium bromide

ZnI2

BaF2

Li2OCaOMgBr2

Naming Binary Ionic Compounds

Give name of cation firstThen name the anionAl2O3

Name of cation: aluminumName of anion: oxideName of compound: aluminum oxide

Naming Binary Ionic Compounds

BaI2

ZnF2

K2OMgOCaBr2

Barium iodideZinc fluoridePotassium oxideMagnesium oxideCalcium bromide

Cations With Different ChargesSome elements form two or more cations

with different chargesFe2+ and Fe3+

Iron (II) and Iron (III)Naming compounds

FeO and Fe2O3

Iron (II) oxide and Iron (III) oxide

Name the Following Compounds

CuOCoF3

SnI4

FeS

Copper (II) oxideCobalt (III) fluorideTin (IV) iodide Iron (II) sulfide

Quiz- Name the Following Compounds

1. K2S2. AgBr3. Na2O4. FeCl25. BaS

6. Lithium fluoride7. Silver iodide8. Iron (III) oxide9. Magnesium iodide10. Gold chloride

Polyatomic Ions Ions that contain two or more atomsMost are negatively chargedList of polyatomic ions is on handout

**MEMORIZE THEM!!!**Examples:

CN- cyanideHCO3

- hydrogen carbonate (bicarbonate)NH4

+ ammonium

Polyatomic IonsYou will need to memorize the following:

Ammonium NH4+1

Acetate C2H3O2-1

Hydroxide OH-1

Nitrite NO2-1

Nitrate NO3-1

Bicarbonate HCO3-1

Carbonate CO3-2

Chromate CrO4-2

Sulfate SO4-2

Phosphate PO4-3

OxyanionsPolyatomic ions that contain oxygenName depends on number of oxygen

atoms

Oxyanions (cont.) If two oxyanions-

Most oxygens: -ateLeast oxygens: -ite

ExampleNO3

- : nitrateNO2

- : nitrite

Oxyanions (cont.) If more than two oxyanions

Most oxygens: “Per- …. –ate” “-ate” “-ite” Least oxygens: “Hypo- …. –ite”

Example ClO4

- : perchlorate ClO3

- : chlorate ClO2

- : chlorite ClO- : hypochlorite

Polyatomic Ion Quiz

Sodium hypochloritePotassium sulfateMagnesium peroxideAmmonium chlorideLithium nitratePotassium phosphate

NaClOK2SO4

MgO2

NH4ClLiNO3

K3PO4

Polyatomic Ion Quiz1. Bicarbonate2. Acetate3. Bisulfite4. Permanganate5. Nitrite6. Cyanide7. Hydroxide8. Bisulfate9. Nitrate10. What’s your favorite polyatomic ion?

Binary Molecular CompoundsComposed of molecules (covalently

bonded!)A nonmetal bonded to another nonmetalExamples:

SO3

ICl3CH4

H2O

Prefixes for Naming Binary Molecular Compounds

1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca

Naming Binary Molecular Compounds

Which element goes first? Smaller group number If same group- greater period number Use prefix only if there is more than one atom

Second element Prefix indicating number of atoms + root of the name

of the element + -ide General order of elements in binary compounds:

C, P, N, H, S, I, Br, Cl, O, F

Naming Binary Molecular Compounds

Examples:SO3 – sulfur trioxideBrCl3 – bromine trichloridePBr5 – phosphorus pentabromideN2O5 – dinitrogen pentoxide

Naming Binary Molecular Compounds

N2OCCl4NOCO2

N2O3

P4O10

Dinitrogen monoxideCarbon tetrachlorideNitrogen monoxideCarbon dioxideDinitrogen trioxideTetraphosphorus decoxide

Naming Binary Molecular Compounds- More Practice!

Disulfur dioxideSilicon tetrafluorideSulfur monoxidePhosphorus trioxideBoron trifluorideDiphosphorus pentoxide

S2O2 SiF4

SOPO3

BF3

P2O5

Acids Acid- a type of molecular compound

Two types Binary acids- made up of two elements- hydrogen, and one

of the halogens (F, Cl, Br, I) Oxyacids- contain hydrogen, oxygen, and a third element

Examples Binary acids:

HCl- hydrochloric acid; HF- hydrofluoric acid Oxyacids:

H2SO4: sulfuric acid HNO3: nitric acid

Formula MassThe sum of the atomic masses of all

atoms represented in its formulaUnits = amu (atomic mass units)Example: What is the formula mass of

water?2 H atoms @ 1.01 amu each = 2.02 amu1 O atom @ 16.00 amu each = 16.00 amuTotal mass of water = 16.00 + 2.02 = 18.02

Formula MassFind the formula mass of the following:

KClO3

H2SO4

Mg(NO3)2

C12H22O11

Molar MassThe mass in grams of one mole of a

substance If we have 1 mole of H2O, we have

2 moles of H atoms1 mole of O atoms

Molar Mass (cont.)How many moles of each atom are in the

following?CaCl2NaOHKMnO4

NH4OHMg(NO3)2

Molar Mass (cont.)Once we know the number of moles of

each atom, we can calculate the molar mass.

In H2O:2 moles H x 1.01 g H = 2.02 g H

1 mole H

1 mole O x 16.00 g O = 16.00 g O 1 mole O

Molar Mass (cont.)

Total mass of 1 mole H2O 2.02 g + 16.00 g = 18.02 g/mol

Molar Mass (cont.)Determine the molar mass of the following:

CaCl2NaOHKMnO4

NH4OHMg(NO3)2

Molar Mass as a Conversion Factor

Can use molar mass as a conversion factor to determine number of moles

How many moles of H2O are in 34.32 g?

Molar Mass as a Conversion Factor

How many molecules of NaCl can be found in a sample containing 45.43 g?

Molar Mass as a Conversion Factor

How many carbon atoms are in a 23.43 g sample of CO2?

Fun With Conversions! Ibuprofen, C13H18O2, is the active

ingredient in Advil. Find its molar massIf the tablets in the bottle contain a total of 33

g of ibuprofen, how many moles of ibuprofen are in the bottle?

How many molecules of ibuprofen are in the bottle?

What is the total mass in grams of carbon in 33 g of ibuprofen?