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8/10/2019 1- Chapeter 3 Matter Properties and Change
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Matter-Properties andChanges
Chemistry is the study of matter and it's properties . Every aspect
these divers' environment, under water and on land,is some form of matter.
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Properties of Matter The diversity of matter in the world and in the universe is astounding
(fabulous) Chemistry is the study of matter Matter is anything that has mass and takes up space. Everything around you is matter, including things such as air and microb
which you cannot see.
Matter that has a uniform and unchanging composition (as color, odor,taste, hardness, melting point, and boiling point) is called a substa Salt Water
Seawater is not a substance because samples taken from different locatiowill probably have differing compositions
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Physical Properties of Matter
A physical property is a characteristic that can be observed ormeasured without changing the sample's composition. Physical properties describe pure substance too. PP descri
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Physical Properties of CommonSubstances
Physical Properties of common Substances
Substance Color State at 25 Melting point Boiling point Den
Oxigen Colorless Gas -218 -183
Mercury Silver Liquid -39 357
Water Colorless Liquid 0 100
Sucrose White Solid 185 Demposes 1Sodium chloride White Solid 801 1413 2
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Physical Properties :Extensive (amplio) and intensive (intensive) properti
Extensive properties are dependent upon the amount of substancepresent Mass Length (largo) Volume
Intensive properties are independent of the amount of substancepresent
Density (at constant temperature and pressure) is the same no matter howmuch substance is present.
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Chemical Properties of Matter
Chemical property is the ability ofa substance to combine with orchange into one or more othersubstances.
The ability of iron to form rust Inability of a substance to change into
another substance Iron does not undergo a change in
the presence of nitrogen
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Observing Properties of Matter
Every substance has its own unique set of physical and chemicalproperties Observations of properties may vary depending on the conditions o
the immediate environment. It is important to state specific conditions in which observations are
made because both chemical and physical properties depend ontemperature and pressure. The properties of water are dramatically different under different condition.
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States of Matter = physical forms Forms of matter: solid , liquid , gas Solid : a form of matter that has its own definite shape and
volume. The particles of matter in a solid are very tightly packed; when heated,
a solid expands, but only slightly. Solid is not defined by its rigidity or hardness
Liquids : a form of matter that flows, has constant volume, and
takes the shape of its container. Water, blood, and mercury The particles in a liquid are not rigidly held in place and are less packed than are the
particles in a solid Liquid particles are able to move past each other. This allows a liquid to flow and
take the shape of its container. Like solids, liquids tend to expand when heated.
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Gases : a form of matter that flows to conform to the shape of its container athe entire volume of its container.
Neon, methane, air Compared to solids and liquids, the particles of gases are very far apart. Vapor did not mean the same thing. Gas refers to a substance that is naturally in the gaseous state at room
temperature. Vapor refers to gaseous state of a substance that is a solid or a liquid at room
temperature.
http://www.chem.purdue.edu/gchelp/atoms/states.html
States of Matter = physical forms
http://www.chem.purdue.edu/gchelp/atoms/states.htmlhttp://www.chem.purdue.edu/gchelp/atoms/states.htmlhttp://www.chem.purdue.edu/gchelp/atoms/states.html8/10/2019 1- Chapeter 3 Matter Properties and Change
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Section 3.2Changes in Matter
Scientists can describe matter in terms
of physical and chemical properties
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Physical Changes
Physical changes : Changes which alter a substance without changits composition. Cutting a sheet of paper and breaking a crystal
The state of matter depends on the temperature and pressure of thesurroundings.
As temperature and pressure change, most substances undergo a changefrom one state (or phase) to another.
Ice and water have different appearances, but their composition isthe same.
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Chemical changes
Chemical properties relate to the ability of a substance to combinewith or change into one or more substances. Chemical change is a process that involves one or more substance
changing into new substances. (chemical reaction) The new substances formed in the reaction have different
compositions and different properties from the substances presentbefore the reaction occurred. The crushing of grapes that is part of the wine-making process is a physica
change, but the fermentation of the juice, sugars and other ingredients towine is a chemical change .
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Evidence of a chemical reaction
A chemical reaction always produces a change in properties Rust has different properties than the reactants (iron and oxygen) is evidencthat a chemical reaction has taken place.
Rust is not attracted to a magnet, whereas iron is.
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Conservation of Mass By carefully measuring mass before and after chemical reactions, it was
observed that although chemical changes occurred, the total mass involvin the reaction remained constant.
The law of conservation of mass states that mass is neither created nor destroyedduring a chemical reaction it is conserved .(18th century)
The equation form of the law of conservation of mass is:
Mass reactants = Mass products The French scientist Antoine Lavoiser was one of the first to use an analytical bal
(p. 63) Lavoisier's experimental decomposition of mercuryII oxide is one proof of the law
conservation of mass. Although a chemical reaction is obvious (powder to liquidmercury), matter was neither created nor destroyed
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Elements and
CompoundsSection 3.4
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Elements All matter can be broken down into a relatively small number of basi
building block called elements. An element is a pure substance that cannot be separated into sim
substances by physical or chemical means. Naturally occurring elements
Copper Oxigen
Gold On Earth 91 elements occur naturally. There are also several elements that do not exist naturally but have
been developed by scientists.
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A first look at the periodic table New elements discovered in the 19th century
Several schemes 1869 the Russian chemist Dmitri Mendeleev
devised the chart shown in this figure whichorganized all of the elements that wereknown into rows and column based on their
similarities and masses. (First version ofperiodic table).
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The periodic table organizes the elements into a grid(cuadro) of horizontal rows called periods and verticalcolumns called groups or families.
Elements in the same group have similar chemicaland physical properties.
The table is called periodic because the pattern of
similar properties repeats as you move from periodto period.
The periodic table remains a dynamic tool asscientist continue to discover new elements.
A first look at the periodic table
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Compounds
Remember: The matter is classified as pure substances and m ixtures . Mixtures can be homogeneous or heterogeneous . Elements are pure substances that cannot be separated into sim
substances.
Another classification of pure substances: Compounds .
Is a combination of two or more different elements that are combinedchemically.
Much of the matter of the universe are compounds .
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Compounds There are approximately 10 million known compounds and new
compounds continue to be developed. Table salt Table sugar Aspirin Water
Several organizations have have assumed the task of collecting dataand indexing the known chemical compounds.
These organizations maintain huge databases that allow researchersto access information on existing compounds.
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Compounds The chemical symbols of the periodic table make it easy to w
formula for chemical compounds. Sodium chloride: NaCl Water: H 2O
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Compounds Unlike elements, compounds can be
broken down into simpler substances bychemical means .
To separate a compound into its elementsoften requires external energy such asheat or electricity.
The next figure shows the apparatus usedto produce chemical change of water intoits component elements of hydrogen andone part oxygen.
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Law of Definite Proportions According to the law of definite
proportions, samples of acompound from any source musthave they same massproportions.
Conversely, compounds withdifferent mass proportions mustbe different compounds.
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Shapes of matter Shape Space betweenparticles
Volume Particle motion Compressibility Is it a fluidor n
Solid Fixed shape Particles really pressedtogether
Yes, definitevolume
Yes- vibrate Virtually incompressible No
Liquid No fixed shape Particles can move/slide past one another
Yes, constant(takes the shape ofits container)
Yes- Vibrate Slightly compressible Yes
Gas No definiteshape/volume
Particles are very farapart
Yes, but haveneither fixedvolume nor shape
Yes- vibrategas vibrate and move freelyat high speeds
Easily compressed. Yes
Plasma No definiteshape/volume
Free space between particles
No definite volume. Yes, the particles movesfaster
Compressible (the plasma must be able to deal with the hightemperatures)
Yes but bcharg
prese plasmto andelectrforce
The density , or more precisely, the volumetric mass density , of a substance is its mass per unit volume . The symbol most often used for density is (the lower case Greek letter rho ). Matby volume: [1]
where is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume ,[2] aquantity is more specifically called specific weight .For a pure substance the density has the same numerical value as its mass concentration . Different materials usually have different densities, and density may be relevant to buoyancy , puritdensest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser.
Solids and liquids are virtually incompressible because the molecules are already in contact,there is no possibility of a change in volume with an increase in pressure
A gas is a substance with no definite volume and no definite shape. Solids and liquids havevolumes that do not change easily. A gas, on the other hand, has a volume that changes to matchthe volume of its container. Compress aumenta
la presin y reduces el
volumenfor gases, the density can vary over a wide range because the molecules are free to move.
CENSORED
http://en.wikipedia.org/wiki/Masshttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Rho_(letter)http://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Weighthttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Specific_weighthttp://en.wikipedia.org/wiki/Mass_concentration_(chemistry)http://en.wikipedia.org/wiki/Buoyancyhttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Standard_conditions_for_temperature_and_pressurehttp://en.wikipedia.org/wiki/Buoyancyhttp://en.wikipedia.org/wiki/Mass_concentration_(chemistry)http://en.wikipedia.org/wiki/Mass_concentration_(chemistry)http://en.wikipedia.org/wiki/Mass_concentration_(chemistry)http://en.wikipedia.org/wiki/Specific_weighthttp://en.wikipedia.org/wiki/Specific_weighthttp://en.wikipedia.org/wiki/Specific_weighthttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Weighthttp://en.wikipedia.org/wiki/Densityhttp://en.wikipedia.org/wiki/Rho_(letter)http://en.wikipedia.org/wiki/Volumehttp://en.wikipedia.org/wiki/Mass8/10/2019 1- Chapeter 3 Matter Properties and Change
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