Chapter Objectives: Section 2.1 1. Identify the characteristics of matter and substances...
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Chapter 2 Matter & Change Chapter Objectives: Section 2.1 1. Identify the characteristics of matter and substances 2. Differentiate among the three states of matter 3. Define physical property and list several common physical properties of substances Section 2.2 4. Categorize a sample of matter as a substance or a mixture 5. Distinguish between homogeneous and heterogeneous samples of matter Section 2.3 6. Explain the difference between an element and a compound 7. Identify the chemical symbols of common elements, and name common elements, given their symbols Section 2.4 8. Differentiate between physical and chemical changes in matter 9. Apply the law of conservation of mass
Chapter Objectives: Section 2.1 1. Identify the characteristics of matter and substances 2.Differentiate among the three states of matter 3.Define physical
Chapter Objectives: Section 2.1 1. Identify the characteristics
of matter and substances 2.Differentiate among the three states of
matter 3.Define physical property and list several common physical
properties of substances Section 2.2 4. Categorize a sample of
matter as a substance or a mixture 5.Distinguish between
homogeneous and heterogeneous samples of matter Section 2.3 6.
Explain the difference between an element and a compound 7.Identify
the chemical symbols of common elements, and name common elements,
given their symbols Section 2.4 8. Differentiate between physical
and chemical changes in matter 9.Apply the law of conservation of
mass
Slide 3
States of Matter Prentice-Hall 2002General Chemistry: Chapter 1
Slide 2 of 19
Slide 4
Some Properties of Solids, Liquids, and Gases Property Solid
Liquid Gas Shape Has definite shapeTakes the shape of Takes the
shape the container of its container Volume Has a definite
volumeHas a definite volume Fills the volume of the container
Arrangement of Fixed, very closeRandom, close Random, far apart
Particles Intermolecular Very strongStrong Essentially none
forces
Slide 5
Kinetic theory All particles have energy and move Higher
temperature = faster movement At the same temperature (energy),
smaller particles/atoms will move faster than heavier ones. The
kinetic theory explains the differences between the states of
matter: Solid has definite shape and definite volume; the particles
in a solid are packed closely together (least energy) Liquid has a
definite volume, but does not have a definite shape; particles are
further apart than in solids (more energy) Gas does not have a
definite shape and does not have a definite volume (expands as much
as possible); particles are spread far apart (most energy)
Slide 6
Matter Substance Definite composition (homogeneous) Substance
Definite composition (homogeneous) Element (Examples: iron, sulfur,
carbon, hydrogen, oxygen, silver) Element (Examples: iron, sulfur,
carbon, hydrogen, oxygen, silver) Mixture of Substances Variable
composition Mixture of Substances Variable composition Compound
(Examples: water. iron (II) sulfide, methane, Aluminum silicate)
Compound (Examples: water. iron (II) sulfide, methane, Aluminum
silicate) Homogeneous mixture Uniform throughout, also called a
solution (Examples: air, tap water, gold alloy) Homogeneous mixture
Uniform throughout, also called a solution (Examples: air, tap
water, gold alloy) Heterogeneous mixture Nonuniform distinct phases
(Examples: soup, concrete, granite) Heterogeneous mixture
Nonuniform distinct phases (Examples: soup, concrete, granite)
Chemically separable Physically separable Classification of
Matter
Slide 7
Pure Substances Element composed of identical atoms EX: copper
wire, aluminum foil Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem
Slide 8
Top Ten Elements in the Universe Percent Element (by atoms)
1.Hydrogen73.9 2.Helium24.0 3.Oxygen 1.1 4.Carbon 0.46 5.Neon 0.13
6.Iron 0.11 7.Nitrogen 0.097 8.Silicon 0.065 9.Magnesium 0.058
10.Sulfur 0.044 A typical spiral galaxy (Milky Way is a spiral
galaxy)
Slide 9
Pure Substances Compound composed of 2 or more elements in a
fixed ratio properties differ from those of individual elements EX:
table salt (NaCl) Sodium Chlorine gas used in WWI
Slide 10
Pure Substances Law of Definite Composition A given compound
always contains the same, fixed ratio of elements. Law of Multiple
Proportions Elements can combine in different ratios to form
different compounds. Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem
Slide 11
Pure Substances For example Two different compounds, each has a
definite composition. Carbon, C Oxygen, O Carbon monoxide, CO
Carbon, C Oxygen, O Oxygen, O Carbon dioxide, CO 2 Courtesy Christy
Johannesson www.nisd.net/communicationsarts/pages/chem
Slide 12
Mixtures Variable combination of two or more pure substances.
HeterogeneousHomogeneous Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem
A Distillation Apparatus liquid with a solid dissolved in it
thermometer condenser tube distilling flask pure liquid receiving
flask hose connected to cold water faucet
Slide 15
Elements, Compounds, and Mixtures (a) an element (hydrogen) (b)
a compound (water) (c) a mixture (hydrogen and oxygen) (d) a
mixture (hydrogen and oxygen) Dorin, Demmin, Gabel, Chemistry The
Study of Matter, 3 rd Edition, 1990, page 68 hydrogen atoms
hydrogen atoms oxygen atoms
Properties & Changes in Matter Physical vs. Chemical
Extensive vs. Intensive
Slide 18
C. Johannesson Physical vs. Chemical Properties Physical
Property can be observed without changing the identity of the
substance Chemical Property describes the ability of a substance to
undergo changes in identity Bromine Aluminum Sodium
Slide 19
C. Johannesson Physical vs. Chemical Properties Examples:
melting point Flammable Density Magnetic tarnishes in air physical
chemical physical chemical
Slide 20
C. Johannesson Physical vs. Chemical Physical Change changes
the form of a substance without changing its identity properties
remain the same Steel rusting: Chemical ChangeSteel rusting:
changes the identity of a substance products have different
properties 4 Fe + 3 O 2 2 Fe 2 O 3
Slide 21
C. Johannesson Physical vs. Chemical Signs of a Chemical Change
change in color or odor formation of a gas (not from boiling!)
formation of a precipitate (solid) from two liquids change in light
or heat
Slide 22
C. Johannesson Physical vs. Chemical Changes Examples: rusting
iron dissolving in water burning a log melting ice grinding spices
chemical physical chemical physical
Slide 23
C. Johannesson Extensive vs. Intensive Extensive Physical
Property depends on the amount of matter present Examples: mass,
volume, heat Intensive Physical Property depends on the identity of
substance, not the amount color, melting point, boiling point,
odor, density, temperature
Slide 24
C. Johannesson Extensive vs. Intensive Examples: boiling point
volume mass density conductivity intensive extensive intensive
Slide 25
Physical and Chemical Properties Examples of Physical
Properties Boiling point Color SlipperinessElectrical conductivity
Melting point TasteOdorDissolves in water Shininess (luster)
SoftnessDuctilityViscosity (resistance to flow) Volatility
HardnessMalleabilityDensity (mass / volume ratio) Examples of
Chemical Properties Burns in air Reacts with certain
acidsDecomposes when heated Explodes Reacts with certain
metalsReacts with certain nonmetals Tarnishes Reacts with waterIs
toxic Chemical properties can ONLY be observed during a chemical
reaction!
Slide 26
Physical & Chemical Changes Limestone, CaCO 3 crushing
PHYSICAL CHANGE Crushed limestone, CaCO 3 heating CHEMICAL
CHANGEPyrex CO 2 CaO Lime and carbon dioxide, CaO + CO 2
Slide 27
Pyrex O2O2 H2OH2OPyrex H2O2H2O2 Light hastens the decomposition
of hydrogen peroxide, H 2 O 2. The dark bottle in which hydrogen
peroxide is usually stored keeps out the light, thus protecting the
H 2 O 2 from decomposition. Sunlight energy H H O O
Slide 28
Chemical Properties and Chemical Change Chemical change or
chemical reaction transformation of one or more atoms or molecules
into one or more different molecules. Chemical change or chemical
reaction transformation of one or more atoms or molecules into one
or more different molecules. Burning hydrogen (H 2 ) in oxygen (O 2
) gives H 2 O.Burning hydrogen (H 2 ) in oxygen (O 2 ) gives H 2
O.
Slide 29
2 H 2 O2O2 O2O2 2 H 2 O + + + + E E Copyright 2007 Pearson
Benjamin Cummings. All rights reserved.
Slide 30
The Zeppelin LZ 129 Hindenburg catching fire on May 6, 1937 at
Lakehurst Naval Air Station in New Jersey.
Slide 31
Hydrogen is the most effective buoyant gas, but is it highly
flammable. The disastrous fire in the Hindenburg, a hydrogen-filled
dirigible, in 1937 led to the replacement of hydrogen by
nonflammable helium.
Slide 32
Packing of NaCl Ions Electron Microscope Photograph of
NaCl
Slide 33
Dissolving of Salt in Water NaCl(s) + H 2 O Na + (aq) + Cl -
(aq) Cl - ions Na + ions Water molecules
Slide 34
Thermal Expansion Most objects e-x-p-a-n-d when heated Large
structures such as bridges must be built to leave room for thermal
expansion All features expand together COLD HOT Cracks in
sidewalk.