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# Chemical Compounds - PowerPoint PPT Presentation

Chemical Compounds. Honors Chemistry. 3 Types of Formulas. Empirical : Smallest whole-number-ratio of atoms or ions in a compound Ex. CH 2 NH 3 Molecular : Tells you the actual number of atoms of an element in a compound Ex. C 2 H 4 N 2 H 6

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### Chemical Compounds

Honors Chemistry

• Empirical: Smallest whole-number-ratio of atoms or ions in a compound

• Ex. CH2 NH3

• Molecular: Tells you the actual number of atoms of an element in a compound

• Ex. C2H4 N2H6

• Structural: Indicates how the atoms are bonded to each other

REMEMBER

Atoms are too small to count or mass individually.

It is easier to count many or mass many.

amu gram

(atomic scale) (macroscopic scale)

mole

atoms, ions, molecules, or formula units

Molar Mass= mass, in grams, per 1 mole of a substance units = grams/mole (g/mol)

• Example: the molar mass of H2O is

18.0 g/mol

Molecular formulas and molar masses are used to determine Percent Composition

• Definition: percentage, by mass, of each element

in a compound

% Composition = (part/whole) x 100

• Problems

• Calculate the % composition of NaCl

% Na:

% Cl:

39.3% Na

60.7% Cl

Percent Composition of Hydrate Percent CompositionDefinition: A hydrate is an ionic compound with water embedded in it.

• Calculate the % water in a hydrate, Mg3(PO4)2. 6H2O.

molar mass of hydrate =

molar mass of anhydrate + x(molar mass of water)

% water =

370.9 g/mol Mg3(PO4)2 . 6H2O

29.1% H2O

How can you identify different types of compounds? Percent Composition

• Type of Compound Identification

• Ionic Begins with a metal

• Covalent Begins with a nonmetal

• Acid Begins with a hydrogen and is aqueous

• Hydrate Ionic Compound and Water

Ionic Compounds Percent Composition

• Made from a positively and negatively charged ion

• Overall charge of the compound is zero

• Types of Ionic Compounds

• Binary

• Ternary

Binary Compounds: Percent CompositionComposed of two monatomic ions

• Primary Rules for Charges: YOU MUST KNOW THESE RULES

1 or IA +1

2 or IIA +2

3 or IIIA +3

15 or VA -3 in binary compounds with metals, H, or NH4+

16 or VIA -2 in binary compounds with metals, H, or NH4+

17 or VIIA -1 in binary compounds with metals, H, or NH4+

Ionic Compounds Percent Composition – look at charges; roman numerals needed for elements with more than one charge (polyvalent)

a. Binary Compounds – only monatomic ions in compound

sodium chloride

iron(III) sulfide

FeS

NaCl

Fe2S3

iron(II) sulfide

Ionic Compounds Percent Composition

Binary Compounds

HF(g)

AlCl3

Cr2O3

hydrogen fluoride

aluminum chloride

chromium(III) oxide

Ionic Compounds Percent Composition

Ternary Compounds– contain 1/more polyatomic ions in compound

sodium carbonate

chromium(III) oxalate

ammonium sulfate

Na2CO3

Cr2(C2O4)3

(NH4)2SO4

Ionic Compounds Percent Composition

• Ternary

Co3(AsO4)2

CuSO3

Note for polyatomic ions:

-ate vs. –ite

per- and hypo-

cobalt(II) arsenate

copper(II) sulfite

Ionic Compounds Percent Composition

• magnesium hydroxide

• calcium sulfate

• ammonium phosphate

Mg(OH)2

CaSO4

(NH4)3PO4

1 extra oxygen Percent Composition

ClO4-1

perchlorate

per_____ ate

ClO3-1

chlorate

the most common form

_______ate

1 less

oxygen

ClO2-1 chlorite

_______ ite

2 less

oxygens

ClO-1

hypochlorite

hypo_____ ite

Now try these… Percent Composition

• sulfite

• periodate

• phosphite

• bisulfite

SO3-2

IO4-1

PO3-3

HSO3-1

Check for Understanding Percent Composition

MgH2

• magnesium hydride

• calcium acetate

• FeS2O3

• SnI4

Ca(CH3COO)2

iron (II) thiosulfate

tin (IV) iodide

Molecular Compounds Percent Composition– formed between 2 nonmetals

*Use prefixes

mono = 1 hexa = 6

di = 2 hepta = 7

tri = 3 octa = 8

tetra = 4 nona = 9

penta = 5 deca = 10

Binary Compounds: only 2 elements in the compound; use prefixes and –ide ending

CCl4

N2O5

carbon tetrachloride

dinitrogen pentoxide

More Practice Percent Composition

• dihydrogen monoxide

• nitrogen tetrabromide

• S2O6

H2O

NBr4

disulfur hexoxide

Hydrates Percent Composition– ionic compound with water bonded in its structure

anhydrate . xH2O

• anhydrate  ionic compound

• add prefix to indicate # of water molecules

CuSO4.5H2O

copper(II) sulfate pentahydrate

Acids Percent Composition– compounds that produce hydrogen ions in water

• Mineral Acids

• Binary Acids

1st word: prefix = hydro

root formed from anion

suffix –ide changed to -ic

2nd word: acid

HCl(aq)

HBr(aq)

hydrochloric acid

hydrobromic acid

B. Oxyacids Percent Composition

• 1st word: root from anion

Suffix ate changed to ic

Suffix ite changed to ous

**Exceptions: if you have sulf or phos as roots, change the root to sulfur or phosphor

• 2nd word: acid

HNO3

HNO2

phosphorous acid

Nitric acid

Nitrous acid

H3PO3

Common Acids to Know Percent Composition

hydrochloric acid

• HCl

• H2CO3

• HClO4

• H2SO4

• H3PO4

• HNO3

• CH3COOH = HC2H3O2

carbonic acid

perchloric acid

sulfuric acid

phosphoric acid

nitric acid

acetic acid

Salts Percent Composition

• Ionic compound composed of a cation (positive ion) and an anion (negative ion) from an acid

• NaCl

• CaSO4

• NaHCO3

• NaHSO3

Organic Compounds Percent Composition

• >11 million compounds

• Contain a C-C or C-H bond in combination with

N, O, S, P or halogens

• Simplest = CH4

• Most complex = DNA

Hydrocarbons Percent Composition

• Only have carbon and hydrogen

• Simplest organic compounds

• From petroleum (crude oil)

Organic Compounds Percent Composition

Allotropes of carbon

Allotropes: Different forms of an element in same physical state

Catenation: ability of an element to form chains and/or rings of covalently bonded atoms

Structural Formula Percent Composition

• Indicates the number and types of atoms present in a molecule and also shows the bonding arrangement of the atoms

• One possible isomer of C4H10

• Does not show 3D shape

Naming Organic Compounds Percent Composition

• Alkanes – saturated organic compound

• Contains only single bonds

• General Formula: CnH2n+2

• Alkenes – unsaturated organic compound

• Contains at least one double bond

• General Formula: CnH2n

• Alkynes – unsaturated organic compound

• Contains at least one triple bond

• General Formula: CnH2n-2

• What type of organic compound is C4H10 ?

Naming Hydrocarbons Percent Composition

• Find the longest chain of carbon atoms. Choose the base name that describes the number of carbon atoms in this chain. Use the following endings:

Alkane (ane), Alkene (ene), Alkyne (yne)

Naming hydrocarbons Percent Composition

• Number the carbon atoms in this longest chain beginning at the end nearest the 1st branching.

• If there is branching at equal distances from both ends of the longest chain, begin numbering at the end nearest the branch that is 1st in alphabetical order.

1

2

3

4

Naming Alkenes and Alkynes Percent Composition

• Number the carbon atoms in the chain sequentially, beginning at the end nearer the double or triple bond. If the parent chain has more than 3 carbons, insert the number describing the position of the double or triple bond (indicated by its 1st carbon location) before the base name.

1-butene

2-butene

Branches/ Percent CompositionSubstituents on the Main Chain

The hydrocarbon branches are called alkyl groups:

-CH3 methyl -CH2CH2CH3 propyl

-CH2CH3 ethyl -CH2CH2CH2CH3 butyl

2)The organic halides are elements from group 17 in the periodic table.

The prefix can be fluoro-, chloro-, bromo- or iodo-.

Hydrocarbon Branches or Percent CompositionSubstituents

Assign the name (stem with yl ending) & position number to each substituent or branch. Arrange substituentsin alphabetical order.

The hydrocarbon branches are called alkyl groups:

-CH3 methyl -CH2CH2CH3 propyl

-CH2CH3 ethyl -CH2CH2CH2CH3 butyl

Naming hydrocarbons Percent Composition

• Use the appropriate prefix to group like substituents: di = 2, tri = 3, tetra = 4, etc. Do not use these prefixes when alphabetizing attached groups

• Write the name as a single word. Use hyphens to separate numbers & letters and commas to separate numbers. Do not leave any spaces.

Naming Alkenes and Alkynes Percent Composition

In naming alkenes and alkynes, the mulitple bond takes positional precedence over substituents on the carbon chain. The double bond is assigned the lowest possible number.

3,3-dimethyl-1-butene

4-methyl-2-pentene

Naming Organic Halides Percent Composition(Alkyl Halides)

• The organic halides are named as halo- derivatives of the parent hydrocarbon. The prefix can be fluoro-, chloro-, bromo- or iodo-.

1-chloropropane

1-chloro-2-methylpropane

http://wps.prenhall.com/wps/media/objects/476/488316/index.htmlhttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

Alkene Exampleshttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

3,4-dimethyl-3-hexene

3-ethyl-4,6-dimethyl-1-heptene

Naming Alkyneshttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

• Named just like the alkenes except the suffix –yne is added

ethyne

1-butyne

propyne

2-butyne

Alkyne Exampleshttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

3-methyl-1-butyne

5-methyl-2-hexyne

Arrangement of Atomshttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

• Isomers – compounds that have the same molecular formula but different structures

• More C atoms in formula, more isomers

• 18 isomers for C8H18

• 35 isomers for C9H20

• 75 isomers for C10H22

Isomers of C6H14

Structural Isomershttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

• Isomers in which the atoms are bonded together in different orders.

• C4H10 (note continuous chain of C atoms)

butanemethylpropane

Physical Properties of Structural Isomers http://wps.prenhall.com/wps/media/objects/476/488316/index.html

Ex #1) Butane, Chttp://wps.prenhall.com/wps/media/objects/476/488316/index.html4H10

Ex #2) Butene, C4H8

Ex #3) 2-Butene, C4H8

Ex #4) methyl propene, C4H8

ISOMERS

Functional Groupshttp://wps.prenhall.com/wps/media/objects/476/488316/index.htmlan atom or group of atoms that is responsible for the specific properties of an organic compound

Diffusion and Effusionhttp://wps.prenhall.com/wps/media/objects/476/488316/index.html

Diffusion: the mixing of molecules of 2 or more gases due to their molecular motion (spontaneous)

Effusion is the movement of gas atoms or molecules through a small opening. Gases confined in a container randomly pass through a tiny opening in the container.

ex) hole in a tire; soda bottle (CO2 escaping)

Graham’s Law: http://wps.prenhall.com/wps/media/objects/476/488316/index.htmlThe rate of effusion of a gas is inversely proportional to the square root of its molar mass.

He and SF6 demo