18
Chapter 5: The Structure of Matter
Compounds vs. Mixtures
______
- different substances placed together
- not ______combined
- can be separated by physical means
- each substance keeps its own ______
- can have any amount of each substance
______
- combine in definite ______
- when combined, new substance has its own properties
- chemically combined
- held together by chemical bonds
- ______- the attractive force that holds atoms or
ions together
- chemical ______- shows the types and number of atoms
or ions making up the simplest unit of
the compound
- always the same for a compound
- definite ratio
- Ex.- water is always H2O
- state, location, or amount doesn’t
matter
- H2O2 - hydrogen peroxide
- both H2O and H2O2 have H and
O, but they are very different
- chemical ______- the arrangement of atoms in a
substance
- how atoms are arranged determines
many of a compound’s properties
- 2 important descriptions
1) bond ______- distance between the nuclei of two
bonded atoms
2) bond ______- how the atoms are oriented in space
- applies only when there are three or
more atoms
- ball and ______model- shows bonding and angles
- “ball” represents atoms
- “stick” represents bonds
- ______formula- good for showing structures
- symbol and lines replace ball and stick
- Ex.- O
H H
- ______filling model- shows relationship in how much
space is taken up by each atom
- doesn’t show bond ______and
______
***different structures give different properties***
- Ex.- SiO2 quartz and sand
- forms large network structure
- Si-O-Si
- all bond angles are 109.50
- bond angle continues throughout structure
- ______
- makes it very hard, rigid structure
- takes lots of ______to break bonds
- causes ______in melting and boiling points
- Ex.- NaCl
- crystalline
- repeating ______of strong bonds
- Na+ ions and Cl- ions
- strong attraction = strong bond
- results in high melting and boiling points
- Ex.- sugar (C12H24O12)
- C, H, and O bond together to make a molecule
- strong bonds
- attraction ______molecules is weak
- N2, O2, and CO2
- colorless, odorless, strongly bonded molecules
- almost no attraction between molecules
- allows them to ______
- why gases take up a lot of space
- compounds made of ______have very different
properties
- even though H2O and H2S are similar in structure, the
boiling point and melting point are different
- water’s molecules are more ______to each other
than dihydrogen sulfide’s are
- hydrogen bonds between molecules
- weak bond due to slightly positive and slightly
negative portion of water molecule (______)
- makes water a ______at room temperature
BONDING
- ______- energy that holds atoms together
- type of bond affects ______
- result of valence electrons interacting
- interact until outer energy level is ______
- resemble ______gas
- sometimes represented by sticks
- ______would be more accurate
- nuclei move in all directions
- bond distances are averages of those
movements
3 types of bonds
1) ______Bonding
- result of oppositely charged atoms attracting
- one atom (non-metal) rips electrons away from another
atom (metal)
- metal ions are “____” charged
- ______electrons
- non-metal ions are “______“ charged
- ______electrons
- both are stable as a result of electron movement
- oppositely charged ions attract to form an ionic
compound
- Ex.- NaCl (table salt)
Na+ + Cl-
- sodium ion ______several chlorine ions
- build up of chlorine ions attracts several more
sodium ions
- sets up a ______of bonded ions
- lots of Na+ and Cl- are bonded together
- ratio is 1:1 NaCl
- Ex.- Ca2+ + F-
CaF2
- as crystals, charges are locked into place
- very high melting points
- ______in water or melted
- will ______electricity
- electricity is e- moving from one place to another
- when ______or ______; ions are now free to
move and pass energy through the substance
2) ______Bonds
- bonds formed by the attraction between positively
charged ______ions and the electrons around them
- results in closely ______atoms
- overlapping orbitals
- e- are free to move as they please
1) allows metals to conduct electricity
2) makes them ______
- atoms slide past each other without breaking any
bonds
3) ______Bonds
- bond formed when atoms share one or more pairs of
electrons
- formed between non-metal atoms
- solids, liquids, or gases
- most have ______melting points
- except compounds with network structures
- crystalline
- molecules are free to move when dissolved or melted
- stay intact; do not conduct electricity
- not charged
2 types
1) ______covalent bonds
- bonds which share electrons equally
- Ex.- Cl2
- Chlorine has 7 valence electrons
- shared electrons are attracted to “___”
charged nucleus of other atom
- equal “+” charge; equal sharing
- line between carbon atoms represents one
___ of electrons being shared (single bond)
- Ex.- O2 ______bond
- 2 pairs of electrons shared
- Ex.- N2 ______bond
- 3 pairs of electrons shared
- Ex.- C2 ______bond
- 4 pairs of electrons shared
- most possible
- more bonds = stronger bonds
- requires more energy to break them
2) ______covalent bonds
- shared electrons are not shared ______
- usually electrons are attracted to atoms of
elements that are located further to the ____and
closer to the ______of the periodic table
______Ions
- an ion made of two or more atoms
- have covalently bonded atoms and have lost or gained
electrons
- all are negatively charged except ammonium; NH4+
Monatomic Ions vs. Polyatomic Ions
Monatomic Ions Polyatomic Ions
sodium oxide Na2O sodium sulfate Na2SO4
iron (III) fluoride FeF3 potassium carbonate K2CO3
barium iodide BaI2 calcium chlorate Ca(ClO3)2
copper (II) oxide CuO tin (II) acetate Sn(CH3COO)2
- to I.D. a polyatomic ion:
1) see if ____ is at the beginning of the compound
2) cover up ______element with finger
3) is there more than one element left
- if yes, it is polyatomic
- if no, it is monatomic
- many contain oxygen
- end in –ite or –ate
- ate used for ion with ______oxygen
- ite used for ion with ______oxygen
- Ex.- sulfate SO4 2-
sulfite SO3 2-
nitrate NO3 1-
nitrite NO2 1-
chlorate ClO3 1-
chlorite ClO2 1-
Compound Names and Formulas
- names reflect the elements from which the compounds are
found
Ionic Compounds
- formed from attraction between ______(+) and _____ (-)
- ______is written first; followed by ______
- cation is unchanged
- anion ending is altered
- usually ends in –ide
- Ex.- fluorine; fluoride
- oxygen; oxide
- Ex.- NaCl table salt
- Sodium Chloride
- ______metals
- may form more than one cation
- charge follows cation in compound
- in ______numerals
- Ex.- FeO vs. Fe2O3
- black powder - reddish brown
- melts at 14200 C - rust
- melts at 15650 C
- iron (II) oxide - iron (III) oxide
- total charge on compound is ______
- “+” equal to “-“
Fe2O3
- each oxygen is a -2 charge; 3 molecules
(-2)(3)= -6
- total positives must equal +6
2 Fe atoms = +6
+6/2 = +3 each
Ionic Compound Formulas
1) find charge of each ______
2) write symbol for ______first
3) find ______common multiple of ions’ charges
4) write chemical formula
- ______indicate how many of each ion are needed
to be neutral
- Ex.- Aluminum and Fluoride
1) Al = +3 F = -1
2) Al3+F-
3) least common multiple = 3
4) AlF3 or AlFFF
+3;-1;-1;-1
+3;-3
0; neutral
Polyatomic Ion Formulas
- to determine the charge of a polyatomic ion (2 ways)
1) memorize, memorize, memorize
2) check the ______of the positive part (left side) of
compound
- polyatomic part (______side) must be equal and
opposite
- Ex.- NaOH
Na = +1 so OH must = -1
- Ex.- Na2CO3
Na = +1, there are two atoms Na; = +2
CO3 = -2
- Ex.- Ca(ClO3)2
Ca = +2; right side must equal -2
- there are two ClO3 molecules
- each is a -1 charge
-1 + -1 = -2
Naming Covalent Compounds
- use numerical ______to tell how many atoms of each
element
- which ever element is further to the _____ on the periodic
table is named second and ends in –______
- Ex.- 1 boron and 3 fluorine atoms atoms…BF3
- boron trifluoride
- Ex.- N2O4
- dinitrogen tetroxide
- ______formula- the composition of a compound in
terms of the relative numbers and
kinds of atoms in the simplest ratio
- Ex.- 142 g sample of unknown substance
- found to contain only phosphorus and oxygen
62 g P and 80 g O
62 g P x 1 mol P 80 g O x 1 mol O
30.97 g P 16 g O
2 mol P : 5 mol O
P2O5
- Ex.- CH2O
- empirical formula for formaldehyde, acetic acid,
and glucose
- all are very different
- must use molecular formula to tell the
difference
- ______formula- a chemical formula that shows the
number and kind of atoms in a
molecule, but not the arrangement of
atoms
- sometimes empirical and molecular formulas are the ____
- Ex.- water; both are H2O
empirical formula / molecular formulaformaldehyde / CH2O / CH2O
acetic acid / CH2O / C2H4O2
glucose / CH2O / C6H12O6
- ______compound- covalently bonded compound that
contains carbon
- usually contains hydrogen
- may also contain other atoms
- ______- compound made entirely of carbon and
hydrogen
- carbon has ___ valence electrons for bonding
- maximum number of bonds possible (4)
Alkanes, Alkenes, Alkynes
Alkanes
- hydrocarbons with only ______bonds
- ______- n-alkanes
- when alkanes’ carbons line up in a
straight row
- if 3 or less; always normal
- more than 3; may have branches, rings
prefix / # of carbons / name / molecularformula / condensed structural formula / structural formula
meth / 1 / methane / CH4 / CH4 / c
eth / 2 / ethane / C2H6 / CH3CH3 / c-c
prop / 3 / propane / C3H8 / CH3CH2CH3 / c-c-c
but / 4 / butane / C4H10 / CH3(CH2)2CH3 / c-c-c-c
pent / 5 / pentane / C5H12 / CH3(CH2)3CH3 / c-c-c-c-c
hex / 6 / hexane / C6H14 / CH3(CH2)4CH3 / c-c-c-c-c-c
hept / 7 / heptane / C7H16 / CH3(CH2)5CH3 / c-c-c-c-c-c-c
oct / 8 / octane / C8H18 / CH3(CH2)6CH3 / c-c-c-c-c-c-c-c
non / 9 / nonane / C9H20 / CH3(CH2)7CH3 / c-c-c-c-c-c-c-c-c-
dec / 10 / decane / C10H22 / CH3(CH2)8CH3 / c-c-c-c-c-c-c-c-c-c
Alkenes
- hydrocarbons with at least 1 ______bond (C=C)
- ending is –ene
- smallest is ethane
- must have 2 carbons for double bond
- general formula C___H____
Alkynes
- hydrocarbons with at least 1 ______bond (C=C)
- ends in –yne
- smallest is ethyne
- general formula C____H______
- alcohol (-____ group)
- OH is called a hydroxyl group
- Ex.- methanol (CH3OH)
- ethanol (CH3CH2OH)
- isopropanol (C3H8O or (CH3)2CHOH)
Polymers
- ______- a large molecule that is formed by more than
five monomers or small units
- Ex.- polyethylene
- poly- many
-ethene- alkene (C2H4)
- C2H4 is the monomer
- some occur ______
- Ex.- rubber, wood, cotton, wool, starch, protein, DNA
- some are man made
- usually plastics or fibers
- properties are determined by structure
- polymer ______
- polymer molecules are like a bowl of spaghetti
- chains get tangled, but can slide past each other
- doesn’t keep shape (no memory)
- Ex.- milk jug
- some polymers will ______
- creates “memory”
- returns to its original shape
- Ex.- rubber band
Biochemical Compounds
several important ones, we’ll look at 4
1) ______
- energy for living things
- Ex.- glucose
- glucose is used; unused glucose is stored
- in animals- glycogen
- in plants- starch
2) ______
- storage for energy (extra glucose)
- liquid; ______
- solid; ______
3) ______
- uses
- structural components in cells
- hair
- muscles
- hemoglobin
- made of ______
- 20 amino acids
C
- 20 A.A. are responsible for all proteins we know of
- all but 8 our body can make
- 8 ______A.A. must come from our diet
- eggs, dairy products, organ meats
4) ______
- Ex.- deoxyribonucleic acid (DNA)
- ribonucleic acid (RNA)
- determines genetic make up
DNA
- paired chain or strands
- shape…______
- like a twisted ladder
RNA
- 1 strand
- shape…straight
- DNA and RNA are made of alternating sugar and phosphate molecules connected to 1 of 4 bases (monomers)
1) ______
2) ______
3) ______
4) ______