The Structure of Matter

1
The Structure of Matter

• Chapter 5

2
Compounds and Molecules

• Compounds
• Combined elements
• Different properties from individual elements

3
Compounds and Molecules

• Mixtures
• Each substance keeps its own property
• Amount of each substance can vary
• Blue and yellow paint
• Mix to make green paint, but it is still paint

4
Compounds and Molecules

• Chemical Formulas
• Every compound will always have the same formula
• Shows type and number of atoms present in
  compound
• Water (H2O)
• Sugar (C12H22O11)
• Salt (NaCl)

5
Compounds and Molecules

• Chemical Bonds
• Attractive forces that hold different atoms or
  ions together
• Hydrogen and Oxygen

6
Compounds and Molecules

• Chemical Structure
• Shows how a compounds atoms are connected
• Bond length gives distance between two bonded
  nuclei
• Bond angle tells how the atoms are orientated
  in space

7
Compounds and Molecules

• Models of Compounds
• Ball and stick
• Atoms are represented by ball
• Bonds are represented by sticks

8
Compounds and Molecules

• Structural Formula
• Chemical symbols used instead of balls

9
Compounds and Molecules

• Space-filling Models
• Shows space occupied by atoms
• Harder to see bond lengths and angles

10
Compounds and Molecules

• Structural Properties
• Network structures are strong solids
• High melting/boiling points
• Quartz (SiO2)

11
Compounds and Molecules

• Network of bonded ions
• High melting/boiling points
• Salt (NaCl)

12
Compounds and Molecules

• Molecular structures
• Attractions between atoms causes bonds
• Strength of bonds vary (solid, liquid, gas)

13
Compounds and Molecules

• Hydrogen Bonds
• Attractions between neighboring molecules
  (intermolecular)
• F, O, N

14
Ionic and Covalent Bonding

• Bonding
• Occurs when valence electrons of elements
  interact to form more stable compounds
• Can bend and stretch without breaking
• Like springs

15
Ionic and Covalent Bonding

• Ionic Bonds
• Formed between the transfer of oppositely charged
  ions
• Na Cl-
• Forms networks
• Formula Unit
• NaCl is 11
• Ca2 F- CaF2 12

16
Ionic and Covalent Bonding
17
Ionic and Covalent Bonding

• When dissolved in water, ionic compounds will
  conduct electricity

18
Ionic and Covalent Bonding

• Metallic Bonds
• Metals can conduct electricity
• Metals are malleable
• Forms metallic bonds between neighboring atoms
  (overlapping valence shells)

19
Ionic and Covalent Bonding

• Covalent Bonds
• Made of molecules
• Often formed between nonmetals
• Often have low melting points

20
Ionic and Covalent Bonding

• Covalent bonds share electrons
• Cl2, O2 and N2 cant transfer (both negative)
• Cl-Cl, OO, NN
• Nonpolar Covalent Bonds
• Equal sharing of electrons

21
Ionic and Covalent Bonding

• Polar Covalent Bonds
• The unequal sharing of electrons between two
  different atoms
• NH3

22
Ionic and Covalent Bonding
23
Ionic and Covalent Bonding

• Polyatomic Ions
• Groups of covalently bonded atoms that have
  lost/gained electrons
• HCO3-, OH-, NH4, and CO32-
• NH4 and CO32-
• Use parenthesis with polyatomic ions
• (NH4)2CO3 NOT N2H8SO4

24
Ionic and Covalent Bonding

• Naming polyatomic ions
• Ending in ite (one less oxygen) or ate (one
  more oxygen)
• sulfate (SO42-)
• sulfite (SO32-)
• nitrate (NO3-)
• nitrite (NO2-)
• chlorate (ClO3-)
• chlorite (ClO2-)

25
Compound Names and Formulas

• Naming Ionic Compounds (metal and nonmetal)
• Cation ( charge)
• Anion (- charge)
• Ca2
• F-
• O2-
• N3-
• Li
• B3

26
Compound Names and Formulas

• Cations retain their name
• Na ? sodium
• Na ? sodium ion
• Ca ? calcium
• Ca2 ? calcium ion
• Al ? aluminum
• Al3 ? aluminum ion

27
Compound Names and Formulas

• Anions have altered names
• F ? fluorine
• F- ? fluoride ion
• O ? oxygen
• O2- ? oxide ion
• S ? sulfur
• S2- ? sulfide ion
• N ? nitrogen
• N3- ? nitride ion

28
Compound Names and Formulas

• Combine the names
• Na and Cl- (NaCl)
• sodium chloride
• Ca2 and N3- (Ca3N2)
• calcium nitride
• Al3 and S2- (Al2S3)
• aluminum sulfide

29
Compound Names and Formulas

• Transition cation names need to show their charge
• Use roman numerals
• Fe2 ? iron (II) ion
• Fe3 ? iron (III) ion
• Ti2 ? titanium (II) ion
• Ti3 ? titanium (III) ion
• Ti4 ? titanium (IV) ion

30
Compound Names and Formulas

• Naming transition bonds
• Ti3 and N3-
• titanium (III) nitride
• Cr2 and F-
• chromium (II) fluoride

31
Compound Names and Formulas

• Writing formulas
• lithium fluoride
• Li and F-
• LiF
• magnesium bromide
• Mg2 and F-
• MgF2
• calcium nitride
• Ca2 and N3-
• Ca3N2

32
Compound Names and Formulas

• titanium (III) oxide
• Ti3- and O2-
• Ti2O3
• cobalt (III) hydroxide
• Co3 and OH-
• Co(OH)3
• magnesium phosphate
• Mg2 and PO43-
• Mg3(PO4)2

33
Compound Names and Formulas

• Can you tell the transition cation charges?
• Fe2O3
• Fe3 and O2-
• iron (III) oxide
• CrF3
• Cr3 and F-
• chromium (III) fluoride
• Cu2O
• Cu and O2-
• copper (I) oxide

34
Compound Names and Formulas

• Naming Covalent Compounds (nonmetal and nonmetal)
• Use prefixes
• 1 mono-
• 2 di-
• 3 tri-
• 4 tetra-
• 5 penta-
• 6 hexa-
• 7 hepta-
• 8 octa-
• 9 nona-
• 10 deca-

35
Compound Names and Formulas

• Each atom gets a prefix except if the first has
  only one
• SiO2
• silicon dioxide
• CO
• carbon monoxide
• N2O4
• dinitrogen tetroxide (dropped a)

36
Compound Names and Formulas

• Empirical Formula
• a compounds simplest formula
• To determine
• 142 g sample of a compound contains only 62 g
  phosphorus and 80 g oxygen. Calculate the
  empirical formula.
• Convert 62 g P to moles
• Convert 80 g O to moles
• P2O5

37
Compound Names and Formulas

• Different compounds can have the same empirical
  formula
• CH2O
• Formaldehyde
• Acetic acid
• Glucose
• How do you tell these apart?

38
Compound Names and Formulas

• Molecular formula
• Tells you how many atoms are in one molecule of
  compound
• Formaldehyde
• CH2O
• Acetic acid
• 2x CH2O
• C2H4O2
• Glucose
• 6x CH2O
• C6H12O6

39
Organic and Biochemical Compounds

• Organic compound
• A covalently bonded compound made of carbon
  molecules and usually hydrogen

40
Organic and Biochemical Compounds

• Hydrocarbon
• A carbon with only hydrogens attached

41
Organic and Biochemical Compounds

• Alkanes
• Single covalent bonds
• Pattern formula CnH2n2

42
Organic and Biochemical Compounds

• Methane (CH4)
• Ethane (C2H6)
• Propane (C3H8)
• Butane (C4H10)
• Pentane (C5H12)
• Hexane (C6H14)
• Heptane (C7H16)
• Octane (C8H18)
• Nonane (C9H20)
• Decane (C10H22)

43
Organic and Biochemical Compounds

• Arrangement of Alkanes
• Can be lined in a row
• n-alkane
• Can have branches or rings

44
Organic and Biochemical Compounds

• Alkenes
• Contains a carbon-carbon double bond CC
• Pattern formula CnH2n
• Ethene (C2H4)
• Propene (C3H6)
• Butene (C4H8)

45
Organic and Biochemical Compounds

• Alcohols
• Has an OH group called hydroxyl
• Behaves like water (hydrogen bonding)
• methanol
• ethanol
• isopropanol

46
Organic and Biochemical Compounds

• Polymers
• Have repeating subunits
• Elasticity is determined by structure
• Monomer
• -(C2H4)-n
• Polymer (many monomers)

47
Organic and Biochemical Compounds

• Polymers
• Natural
• Rubber, wood, cotton, wool, starch, protein, DNA
• Man-made
• Plastic or fiber

48
Organic and Biochemical Compounds

• Biochemical Compounds
• Carbohydrate
• Made of C, H, and O
• Provides nutrients to living things
• Breaks down to glucose
• Proteins
• Made of amino acids (C, H, O, and N)
• Breaks down to form needed amino acids
• DNA
• Made of C, H, O, N, and P
• Double helix (like ladder)