transcript
- Slide 1
- Slide 2
- 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
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- 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
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- 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)
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- 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
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- Pure Substances Element composed of identical atoms EX: copper
wire, aluminum foil Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem
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- 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)
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- 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
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- 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
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- 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
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- Mixtures Variable combination of two or more pure substances.
HeterogeneousHomogeneous Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem
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- Methods of Separating Mixtures Magnet Filter Decant Evaporation
Centrifuge Chromatography Distillation
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- 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
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- 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
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- Matter Flowchart Examples: graphite pepper sugar (sucrose)
paint soda Courtesy Christy Johannesson
www.nisd.net/communicationsarts/pages/chem element heterogeneous
mixture compound solution homo. mixture homogeneous mixture
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- Properties & Changes in Matter Physical vs. Chemical
Extensive vs. Intensive
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- 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
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- C. Johannesson Physical vs. Chemical Properties Examples:
melting point Flammable Density Magnetic tarnishes in air physical
chemical physical chemical
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- 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
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- 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
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- C. Johannesson Physical vs. Chemical Changes Examples: rusting
iron dissolving in water burning a log melting ice grinding spices
chemical physical chemical physical
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- 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
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- C. Johannesson Extensive vs. Intensive Examples: boiling point
volume mass density conductivity intensive extensive intensive
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- 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!
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- 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
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- 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
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- 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.
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- 2 H 2 O2O2 O2O2 2 H 2 O + + + + E E Copyright 2007 Pearson
Benjamin Cummings. All rights reserved.
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- The Zeppelin LZ 129 Hindenburg catching fire on May 6, 1937 at
Lakehurst Naval Air Station in New Jersey.
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- 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.
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- Packing of NaCl Ions Electron Microscope Photograph of
NaCl
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- Dissolving of Salt in Water NaCl(s) + H 2 O Na + (aq) + Cl -
(aq) Cl - ions Na + ions Water molecules
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- 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.