AP Chemistry Units 1

1
AP ChemistryUnits 1 2 Introduction

• Salisbury High School

2
Isotopes

• Isotopes naturally occurring atoms of the same
  element that vary in their number of neutrons
• Examples 35Cl 37Cl

3
Relative Abundance

• Relative (percent or natural) abundance how
  often the isotope occurs in nature expressed in
  a percentage
• Example 35Cl has an abundance of 75 37Cl has
  an abundance of 25

4
Significance of Abundance

• In any sample of Cl, 75 of the atoms have a mass
  number of 35 and 25 of the atoms have a mass
  number of 37
• These isotopes are considered when average atomic
  mass is calculated

5
Average Atomic Mass

• The mass reported in the periodic table is the
  weighted average of all naturally occurring
  isotopes

6
Average Atomic Mass

• To Calculate Average Atomic Mass
• 1) Multiply the percent abundance by the mass
  for each isotope
• 2) Add these numbers together to determine the
  average atomic mass

7
Example

• Magnesium has two naturally occurring isotopes
  24Mg and 25Mg. 24Mg has a percent abundance of
  79 and 25Mg has a percent abundance of 21.
  Determine the average atomic mass.
• Ans) 24.2 amu

8
On Your Own

• Calculate the average molar mass of copper, given
  that a natural sample typically consists of
  69.71 copper-63 with an actual mass of 62.94
  grams, and 30.83 of copper-65, which has a molar
  mass of 64.93 g.
• Ans) 63.89 g

9
A Twist on Avg. Atomic Mass

• Calculate the percent abundances of each of
  Borons naturally occurring isotopes.
• Isotope 1 10.012 amu
• Isotope 2 11.009 amu
• Ans) Isotope 1-19.91 Isotope 2-80.09

10
On Your Own

• The element Thallium, Tl, has two naturally
  occurring isotopes. The first isotopes has an
  average mass of 203.059 amu and the second
  isotope has an average mass of 205.059 amu.
  Determine the percent abundance.
• Ans) 29.52 70.48

11
Ionic Formulas

• Ionic Compounds form when e- are lost by metals
  and gained by nonmetals
• They form between metals and nonmetals

12
Formula Writing

• Crisscross charges to determine formulas for
  ionic compounds
• Reduce subscripts to empirical formula form
• EX) sodium chloride

13
Write Formulas

• 1) magnesium oxide
• 2) iron (III) chloride
• 3) calcium nitride
• 4) barium hydroxide

14
Molecular Formulas

• Molecular (Covalent) compounds form between
  nonmetals ONLY
• Electrons are shared

15
Molecular Formulas

• In naming molecular formulas, prefixes are used
• 1 mono 2 di 3 tri
• 4 tetra 5 penta 6 hexa
• 7 hept a 8 octa 9 nona
• 10 deca

16
Hydrates

• Hydrates occur when water molecules attach to
  ionic compounds
• EX) CaCl2 ? 6 H2O

17
Hydrates

• A) MgCO3 ? 5 H2O
• B) CuI2 ? 2 H2O

18
Name the following Hydrates

• EX) Naming
• Regular Name Prefix for of water molecules
  hydrate
• CaCl2 ? 6 H2O
• Calcium chloride hexahydrate

19
Organic Nomenclature

• Organic Nomenclature involves naming organic
  compounds
• All organic compounds contain carbon

20
The Bonding of Carbon

• Carbon has four valence electrons and needs four
  more electrons to obey the Octet Rule
• Organic compounds are very complex

21
Review Name each compound

• CaI2 ? 4 H2O
• CO2
• CH4

22
The Bonding of Carbon

• CH4
• C12H22O11
• Many organic compounds are hydrocarbons

23
Carbon Prefixes

• 1 Carbon Atom Meth-
• 2 Carbon Atoms Eth-
• 3 Carbon Atoms Prop-
• 4 Carbon Atoms But-
• 5 Carbon Atoms Pent-

24
Carbon Prefixes

• 6 Carbon Atoms Hex-
• 7 Carbon Atoms Hept-
• 8 Carbon Atoms Oct-
• 9 Carbon Atoms Non-
• 10 Carbon Atoms Dec-

25
Practice Determine of C

• Methane
• Butane
• Butene
• Propanol
• Pentanoic Acid

26
Saturated Vs. Unsaturated

• Saturated hydrocarbons are compounds in which
  every carbon has four single bonds
• Unsaturated hydrocarbons are compounds in which
  there is at least one carbon having a
  double/triple bond

27
Dot Structures

• Write Dot Structures for
• CH4
• C2H6
• C2H4
• Determine which compounds are saturated and
  unsaturated

28
Alkanes

• Alkanes are the simplest organic compounds they
  contain only carbon and hydrogen
• Alkanes are completely saturated
• Generic Formula CnH(2n 2)

29
Naming Alkanes

• Determine the total number of carbon atoms
• Use the appropriate prefix
• Use -ane as a suffix
• Example CH4 methane
• All bonds are single in alkanes

30
Practice

• Write formulas for
• A) ethane
• B) propane
• C) octane

31
Example
32
Example
33
Example
34
Example
35
Alkenes

• Organic compounds in which there is AT LEAST one
  double bond
• Example C2H4
• General Formula CnH2n

36
Alkenes

• Determine the total number of carbon atoms
• Use the appropriate prefix
• Use -ene as a suffix
• Example C2H4 ethene

37
Alkynes

• Organic compounds in which there is AT LEAST one
  triple bond
• Example C2H2
• General Formula CnH(2n-2)

38
Alkynes

• Determine the total number of carbon atoms
• Use the appropriate prefix
• Use -yne as a suffix
• Example C2H2 ethyne

39
Cycloalkanes

• Organic compounds in which form in a circular
  fashion
• Example C6H12
• General Formula NONE

40
Cycloalkanes

• Determine the total number of carbon atoms
• Use the appropriate prefix
• Use cyclo as a prefix
• Use regular alkane name
• Example C6H12 cycloalkane

41
Benzene

• Benzene (C6H6) is the most common cyclic organic
  compound.
• There are alternating double and single bonds
  between the carbon atoms

42
Naming Branched Hydrocarbons

• 1) For all alkanes, locate the longest
  continuous chain of carbon atoms.
• The number of carbon atoms in the chain
  determines the stem name for the compound
• 2) For alkenes and alkynes, locate the carbon
  atoms in the longest chain that contains the
  multiple bond
• The number of carbon atoms in the chain
  determines the stem name for the compound

43
Naming Branched Hydrocarbons

• 3) Look for groups other hydrogen that may
  appear in the molecule. These are called
  substituted groups.
• Common Substituted Groups Names
• CH3 Methyl
• CH2CH3 (C2H5) Ethyl
• CH2CH2CH3 (C3H7) Propyl
• CH2CH2CH2CH3 (C4H9) Butyl

44
Naming Branched Hydrocarbons

• Common Substituted Groups Names
• Cl Chloro
• Br Bromo
• 4) If more than one substituted group of any
  kind is present, use Greek prefixes to indicate
  the number present
• Di 2, Tri 3, Tetra 4, etc.

45
Naming Branched Hydrocarbons

• 5) Number the longest continuous chain beginning
  with the carbon at the end of the chain.
• 6) Use the number to designate the location of
  the substituted group. If there are more than
  two substituted groups, give each group a number

46
Naming Branched Hydrocarbons

• 7) For Alkanes, always count from the end that
  will give the lowest possible number combination
  of numbers. In other words, start counting from
  the end closest to the substituted groups.
• 8) For Alkenes and Alkynes, always count from
  the end of the chain that the multiple bond is
  closer to disregard the branch chain rule

47
Naming Branched Hydrocarbons

• 9) Use hyphens to separate numbers from names,
  and commas to separate number from each other.
  Substituted groups should be listed
  alphabetically, disregarding the Greek prefixes
• Ex) 2, 3-dimethylpentane
• 3-ethyl- 2, 3-dimethlyhexane

48
Naming Branched Hydrocarbons

• Write Structural Formulas for
• 2, 3-dimethylpentane
• 3-ethyl- 2, 3-dimethlyhexane
• 1, 3-butadiene

49
Other Organic Compounds

• Alcohols contain a hydroxyl group, (-OH)
• Ex) CH3OH
• CH3CH2OH

50
Naming Alcohols

• 1) Indicate the number of the carbon to which
  the OH is attached
• 2) Drop e from the name of the corresponding
  alkane, and add the suffix -ol

51
Naming Alcohols

• Ex) CH3OH
• Methanol
• CH3CH2OH
• Ethanol

52
Naming Alcohols

• 1) CH3CH2CH2OH
• 2) OHCH2CH2CH2CH3

53
Carboxylic Acids

• Include a carboxyl group (-COOH)
• The C has a double bond to one of the oxygen
  atoms and a single bond to the OH

54
Carboxylic Acids

• Examples
• HCOOH
• CH3COOH

55
Naming Carboxylic Acids

• Drop the e from the alkane name and add the
  suffix -oic and acid
• HCOOH
• Methanoic Acid
• CH3COOH
• Ethanoic Acid

56
Naming Carboxylic Acids

• CH3CH2COOH
• CH3CH2CH2CH2COOH

57
Amines

• Amines are weak bases and tend to have
  offensive odors (decaying fish)
• Contain a NH2 group
• Recall Nitrogen only needs 3 bonds to be happy
• CH3NH2

58
Amines

• CH3NH2
• Naming Name the group before the nitrogen and
  add amine
• Ex) CH3NH2
• Methylamine

59
Amines

• Name the following
• CH3CH2NH2
• CH3CH2CH2CH2NH2
• (CH3)3N