Matter, Measurement, and The Language of Chemistry

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Unit 1
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• Matter, Measurement, and The Language of
  Chemistry

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Matter

• Matter anything that has mass and occupies
  space.
• Matter can be classified according to its state
  (solid, liquid or gas.)

3
Matter (continued)

• Matter can also be classified according to its
  composition

4
Matter (continued)

• Pure Substance Composed of only a single type
  of atom or molecule.
• Element Composed of only one type of atom.
  Cannot be chemically broken down into simpler
  substances.
• Compound Composed of two or more elements in
  fixed, definite proportions.
• Mixture Composed of two or more different types
  of atoms or molecules that can be combined in
  variable proportions.

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Heterogeneous Mixtures

• A heterogeneous mixture consists of visibly
  different substances.

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Homogeneous Mixtures

• A homogeneous mixture has the same uniform
  appearance and composition.

7
Properties of Matter

• Physical Properties Characteristics of a
  substance that you can observe.
• Examples mass, volume, color, shape, odor,
  texture, melting point, boiling point, density.
• Chemical Properties - Characteristics of a
  substance that describe how it can be changed
  into a new substance.
• Examples flammability, corrosiveness,
  reactivity, acidity, toxicity.

8
Changes in Matter

• Physical Change A change in physical
  properties, it is still the same substance.
• Chemical Change The change of a substance into
  a new, different substance.

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Metric Measurement

• Metric System The standard measurement system
  used by scientists around the world. Also called
  the International System of Units, or SI. It is
  a decimal system, based on the number 10 and
  multiples of 10.

10
Length

• The basic metric unit of length is the meter (m).
• A meter is a little longer thana yard.  A meter
  is a typical height for a 3-year old child, or
  about the size of two cocker spaniels.

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Mass

• The basic metric unit of mass is the gram (g).
  Mass is measured with a balance.
• A gram is small. A nickel coin has a mass of
  about 5 g.
• To measure larger amounts of mass,a kilogram
  (kg) is usually used. A kg is bigger than a
  pound. A 132 lb. person would have a mass of
  60 kg.

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Temperature

• The SI unit for temperature is the kelvin (K).
• Absolute zero 0 K (-273oC) the coldest
  temperature possible, where all molecular motion
  stops.
• You can convert betweentemperature scales with
  the following formulas

oC (oF -32) / 1.8
K oC 273
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Volume

• The basic metric unit of volume is the liter (L).
• One milliliter (ml) is the same as one cubic
  centimeter (cm3.)
• 2 L is the common size for a bottle of soda.
• 1 ml doesnt even fill up a teaspoon.

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Density

• Extensive Properties depend on the amount of the
  substance. Examples Mass, Volume.
• Intensive Properties (also called characteristic
  properties) are independent of the amount of the
  substance. They can be used to identify
  substances. Example Density.
• Density is the ratio of mass to volume

Density Mass Volume
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Significant Figures

• the non-place-holding digits in a reported
  measurement are called significant figures.
• All non-zero numbers are significant, but some
  zeros in a written number are only there to help
  you locate the decimal point.
• How do you remember which zeros are significant
  and which are not?

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Significant Figures

• The Atlantic Pacific Rule

Pacific (Present) - If decimal point is present,
start with the first non-zero number on the left.
Atlantic (Absent) - If decimal point is absent,
start with the first non-zero number on the right.
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Significant Figures

• Examples How many significant figures?

99,000
2 sig figs
99,000.
5 sig figs
0.0099
2 sig figs
0.0990
3 sig figs
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Calculating with Significant Figures

• When you use your measurements in calculations,
  your answer may only be as exact as your least
  exact measurement.

• For addition and subtraction, round to the fewest
  decimal places.

Example (3 decimals) (1 decimal) (unrounded)
(rounded) 50.259
17.4 67.659
67.7

• For multiplication and division, round to the
  fewest significant figures.

Example (3 sigfigs) (1 sigfig) (unrounded)
(rounded) 0.135 x
20 2.7
3
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Uncertainty in Measurement

• Uncertainty comes from limitations of measuring
  devices, experimental design, experimenter, and
  natures random behavior.
• Accuracy how closea measurement comesto the
  actual value.
• Precision how closemeasurements are to one
  another, or how reproducible they are.

Not Accurate and Not Precise Accurate but Not Precise

Not Accurate but Precise Accurate and Precise
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Accuracy vs. Precision
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Chemical Formulas

• A chemical formula indicates the number of each
  kind of atom in a chemical compound.
• when there is no subscript next to an atom, the
  subscript is understood to be 1.
• Examples
• octane C8H18
• aluminum sulfate Al2(SO4)3

there are 18 hydrogen atoms in the molecule.
there are 8 carbon atoms in the molecule.
Parentheses surround the polyatomic ion to
identify it as a group. There are 3 SO4- groups.
there are 2 aluminum atoms in the formula unit.
22
Chemical FormulasSample Problem

• Count the number of atoms in the following
  chemical formulas
• Solution
• Ca(OH)2
• KClO3
• NH4OH
• Fe2(CrO4)3

1 Calcium,
2 Oxygens,
and 2 Hydrogens
1 Potassium,
1 Chlorine,
and 3 Oxygens
1 Nitrogen,
5 Hydrogens,
and 1 Oxygen
2 Irons,
3 Chromiums,
and 12 Oxygens
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Metals and Nonmetals

• Metals tend to form positive () ions, Nonmetals
  tend to form negative (-) ions.

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Monoatomic Ions

• Monoatomic Ions are ions formed from a single
  atom.
• Some main-group elements tend to form covalent
  bonds instead of ions (ex. C and Si.)

1
3
-1
-3
-2
2
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Monoatomic IonsSample Problem

• Identify each element as either a metal or a
  nonmetal. For main group elements, specify the
  ion that will form
• Metal or Nonmetal Ion
• Na
• Cu
• O
• Au
• Ba
• H
• N
• Al

metal
1
metal
nonmetal
-2
metal
metal
2
nonmetal
1
nonmetal
-3
metal
3
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Chemical Categories by Formula

• Ionic Compounds Formed from metal () ions and
  nonmetal (-) ions.
• Base formula ends with the hydroxide ion (OH-1)
  (ex. KOH, Ca(OH)2, Al(OH)3)
• Metallic Oxide consists of only 2 elements 1
  metal and oxygen (ex. Na2O, MgO, SnO2)
• Oxysalt contains the element oxygen in the form
  of a polyatomic ion (ex. MgSO3, Ni(ClO3)2)
• Salt an ionic compound that cant be classified
  into a more specific category (ex. NaCl, CuBr2)

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Chemical Categories by Formula (continued)

• Molecular Compounds Formed from two or more
  nonmetals.
• Non-metallic Oxide consists of only 2 elements
  1 nonmetal and oxygen (ex. CO2, SO3, P4O10)
• Hydrocarbon consists of only 2 elements
  carbon and hydrogen (ex. CH4, C2H4, C3H8)
• Acids formula begins with hydrogen (H).
• Binary acid contains hydrogen and one other
  element (ex. HCl, H2S, HBr)
• Oxyacid contains oxygen in a polyatomic ion
  (ex. HNO3, H2SO4, H3PO4)

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Chemical Categories by FormulaSample Problem

• To which category does each of the following
  chemical formulas belong?
• Category
• BaSO3
• Ag2O
• Ca(OH)2
• NiF2
• C4H10
• HNO2
• PO5
• HF

oxysalt
metallic oxide
base
salt
hydrocarbon
oxyacid
nonmetallic oxide
binary acid
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Nomenclature Flowchart
Compounds
Compounds
Molecular
Acids
Ionic
Ionic
PrefixSystem
BinaryAcids
Hydro-carbons
Oxyacids
Hydrates
Binary
Binary
PolyatomicIons
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Naming Binary Ionic Compounds

• Binary Compounds are composed of 2 elements.
• The name of the metal () ion is given first,
  followed by the name of the nonmetal (-) ion.
• The first element in the compoundis identified
  simply by its name.
• For the second element, theending of the its
  name is dropped, and the ending -ide is added.
• Examples

Al2O3
aluminum
oxide
potassium
fluoride
KF
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Writing Binary Ionic Compounds

• Rules for writing binary ionic compounds
• Write the symbols for the ions, and their
  charges.Remember The metal () ion is always
  written first.
• Cross over the charges (use the absolute value
  of each ions charge as the subscript for the
  other ion.)
• Simplify the numbers and remove the 1s.
• Example aluminum oxide
• The correct formula for aluminum oxide is

Al3
O2
3
2
Al2O3
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Binary Ionic CompoundsSample Problem

• Write chemical formulas for
• Magnesium Iodide
• Calcium Oxide
• Write the correct names for
• Li2S
• ZnCl2

Solution
Mg2
I
MgI2
1
2
Ca2
O 2
CaO
2
2
Hint Always divide subscripts by their largest
common factor .
Lithium
Lithium Sulfide
Zinc
Zinc Chloride
33
The Stock System

• Most d-block elements (transitionmetals) can
  form 2 or more ions with different charges.
• To name ions of these elements, scientists use
  the Stock system, designed by Alfred Stock in
  1919.
• The system uses Roman numerals to indicate an
  ions charge.
• Example Fe2
• Fe3

iron(II)
iron(III)
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Stock System NamingSample Problem A

• Write the formula and give the name for the
  compound formed by the ions Cr3 and F.
• Solution
• Write the ions side by side, cation first.
• Cross over the charges to give subscripts.
• Chromium forms more than one ion, so its name
  must include the charge as a Roman numeral.

Cr3
F
1
3
CrF3
Fluoride
Chromium (III)
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Stock System NamingSample Problem B

• Write chemical formulas for
• Tin (IV) Iodide
• Iron (III) Oxide
• Write the correct names for
• VF3
• CuO

Solution
I
Sn4
SnI4
1
4
O 2
Fe3
Fe2O3
3
2
-
3
V
F3
Vanadium (III)
Fluoride
-

2
2
Cu
O
Copper (II)
Oxide
Hint Uncross subscripts to get the charges of
the ions.
Be sure to verify the charge of the anion.
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Nomenclature Flowchart
Compounds
Compounds
Molecular
Acids
Ionic
Ionic
PrefixSystem
BinaryAcids
Hydro- carbons
Oxyacids
Hydrates
Binary
PolyatomicIons
PolyatomicIons
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Polyatomic Ions

• A polyatomic ion is a charged group of
  covalently bonded atoms.
• Common endings are -ate or -ite, but there are
  exceptions.
• For more than 1 polyatomic ion, use parentheses
  with the subscript on the outside.
• Example Al2(SO4)3

There are 3 sulfate ions in this compound
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Polyatomic IonsSample Problem

• Write chemical formulas for
• Calcium Hydroxide
• Tin (IV) Sulfate
• Write the correct names for
• (NH4)3 PO4
• Cu(NO3)2

Solution
OH
Ca2
Ca(OH)2
1
2
Sn4
SO4 2
Sn(SO4)2
4
2
Hint Remember to divide subscripts by their
largest common factor .
Ammonium
Phosphate
-
2
Cu
(NO3)2
Copper(II)
Nitrate
Hint Uncross subscripts to get the charges of
the ions.
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Nomenclature Flowchart
Compounds
Compounds
Molecular
Acids
Ionic
Ionic
PrefixSystem
BinaryAcids
Hydro- carbons
Oxyacids
Hydrates
Hydrates
Binary
PolyatomicIons
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Hydrates
Prefix No. of Waters
hemi ½
mono 1
di 2
tri 3
tetra 4
penta 5
hexa 6
hepta 7
octa 8

• Hydrates ionic compounds that contain a
  specific number of watermolecules associated
  with eachformula unit.
• in formula, attached waters follow.
• in name, attached waters indicated byadding
  prefixhydrate after name of ionic compound.
• Example
• CoCl2 6H2O
• cobalt(II) chloride hexahydrate

41
HydratesSample Problem

• Write chemical formulas for
• calcium sulfate hemihydrate
• barium chloride hexahydrate
• Write the correct names for
• CuSO4 5H2O
• LiF 4H2O

Solution
CaSO4 ½ H2O
BaCl2 6H2O
copper (II) sulfate
pentahydrate
lithium fluoride
tetrahydrate
42
Nomenclature Flowchart
Compounds
Compounds
Molecular
Molecular
Acids
Ionic
PrefixSystem
BinaryAcids
PrefixSystem
Hydro- carbons
Oxyacids
Hydrates
Binary
PolyatomicIons
43
The Prefix System

• Molecular compounds are composedof
  covalently-bonded molecules.
• The old prefix system is still used for
  molecular compounds.
• Name the prefix, then the element. Anions end in
  -ide.
• The prefix mono- usually isnt used for cations.
• Examples P4O10 CO

tetraphosphorus
decoxide
carbon
monoxide
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The Prefix SystemSample Problem

• Write chemical formulas for
• dinitrogen trioxide
• carbon tetrabromide
• Write the correct names for
• As2S3
• PCl5

Solution
N2O3
CBr4
diarsenic
trisulfide
phosphorus
pentachloride
45
Nomenclature Flowchart
Compounds
Compounds
Molecular
Molecular
Acids
Ionic
PrefixSystem
BinaryAcids
Hydro- carbons
Hydro- carbons
Oxyacids
Hydrates
Binary
PolyatomicIons
46
Hydrocarbons

• Hydrocarbons are compounds that contain only
  carbon and hydrogen.
• Most fuels are mixtures of hydrocarbons.
• Hydrocarbons containing only single bondsare
  called alkanes. Naming is based on the number of
  carbons , and the suffix ane is added.

Base Name No. of C Base Name No. of C
meth- 1 hex- 6
eth- 2 hept- 7
prop- 3 oct- 8
but- 4 non- 9
pent- 5 dec- 10
47
HydrocarbonsSample Problem

• Write chemical formulas for
• methane
• butane
• Write the correct names for
• C2H6
• C3H8

Solution
CH4
C4H10
ethane
propane
48
Nomenclature Flowchart
Compounds
Compounds
Molecular
Acids
Acids
Ionic
PrefixSystem
BinaryAcids
BinaryAcids
Hydro- carbons
Oxyacids
Oxyacids
Hydrates
Binary
PolyatomicIons
49
Acids

• An acid is a certain typeof molecular
  compound.All acids start with H (e.g. HCl,
  H2SO4).
• Acids can be divided into two categories
• Binary acids are acids that consist of H and a
  non-metal. (e.g. HCl.)
• Oxyacids are acids that contain H and a
  polyatomic ion that includes O (e.g. H2SO4.)

50
Binary Acids

• General rules for naming a binary acid
• Begin with the prefix hydro-.
• Name the anion, but change the ending to ic.
• Add acid to the name.
• Examples
• HCl, hydrochloric acid.
• HBr, hydrobromic acid.
• H2S, hydrosulfuric acid.

51
Oxyacids

• General rules for naming an oxyacid
• Name the polyatomic ion.
• Replace -ate with -ic or -ite with -ous
• Add acid to the name.
• Examples
• H2SO4, sulfuric acid.
• H2SO3, sulfurous acid.
• HNO3, nitric acid.
• HNO2, nitrous acid.

52
Naming AcidsSample Problem

• Write the correct name for each of the following
• HF
• HNO2
• H2S
• H2SO4
• H3PO4

Type of Acid
Name
binary acid
hydro
fluorine
ic acid
oxyacid
nitrite
ous acid
binary acid
hydro
sulfur
ic acid
oxyacid
sulfate
uric acid
oric acid
oxyacid
phosphate
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Heat and Temperature

• Temperature a measure of the average kinetic
  energy of the particles in a sample of matter.
• The greater the kinetic energy of the particles
  in a sample, the hotter it feels.
• Heat energy transferred between samples of
  matter due to a difference in their temperatures.
• Heat always moves spontaneously from matter at
  a higher temperature to matter at a lower
  temperature.

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Measuring Heat

• Heat energy is measured in joules (or calories
  food only)
• Chemical reactions usually either absorb or
  release energyas heat.
• The energy absorbed or released as heat in a
  chemical or physical change is measured in a
  calorimeter.

55
Specific Heat

• A quantity called specific heat canbe used to
  compare heat absorptioncapacities for different
  materials.
• Specific heat the amount of energy required to
  raise the temperature of one gram of a substance
  by 1C or 1 K.
• Specific heat can be measured in units of
  J/(gC), J/(gK), cal/(gC), or cal/(gK).

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Heat Transfer Equation

• Specific heat can be used to find the quantity of
  heat energy gained or lost with a change in
  temperature according to the following equation
• Where the variables stand for the following Q
  heat transferred (joules or calories) m mass
  (g) cp specific heat ?T change in
  temperature (oC or K)

Q mcp?T
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Heat Transfer EquationSample Problem

• A 4.0 g sample of glass was heated from 274 K to
  314 K, a temperature increase of 40. K, and was
  found to have absorbed 32 J of energy as heat.
• What is the specific heat of this type of glass?
• b. How much energy will the same glass sample
• gain when it is heated from 314 K to 344 K?

32 J
Q m x cp x ?T

0.20 J/(gK)
cp
(4.0 g)
(40. K)
32 J
(4.0 g)
(cp)
(40. K)
Q m x cp x ?T
Q
(4.0 g)
(0.20 J/(gK))
(30 K)
24 J