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CH. 2 MATTER AND CHANGE.
Properties of MatterMatter is any substance that has mass and
takes up space. All objects contain matter.Matter is classified in two forms:
Heterogeneous material Homogeneous material.
Matter is divided into 3 types:Elements CompoundsMixtures
MIXTURES- CLASSIFYING MIXTURESHETEROGENEOUS MATERIAL
Heterogeneous means more than one type of substance. Heterogeneous matter exists in the form of mixtures.A mixture is matter that consists of two or more
different materials.Mixtures can be separated by physical means.Mixtures have phases, which are any region
with a uniform set of properties.The boundaries between these phases are
called interfaces.
HOMOGENEOUS MATERIALHomogeneous means only one type of a
substance.Homogeneous matter is matter that is
uniformly mixed and cannot be separated easily.
Homogeneous matter exist in several forms:
Pure Substances- Elements & CompoundsSolutions
Solutions consist of solute (dissolved material) and solvent (dissolving material).Solute particles are very small and are
scattered in the solvent and appear as uniform.
Solutions are not always liquid.
ELEMENTS AND COMPOUNDSDISTINGUISHING BETWEEN ELEMENTS AND COMPOUNDS
There are two types of pure substances.
Elements Compounds.
Substances made of only one kind of atom are called elements.Substances made of more than one kind of substances are called compounds.
ELEMENTS: SIMPLIST KIND OF MATTER Elements are the
building blocks for all other substances.Cannot be broken down
into simpler substances.All atoms of an element
have the same number of protons. There are 109 of these
currently listed and named on the Periodic Table
ELEMENTS: 4 BASIC TYPES OF ELEMENTS Metals: found on the left and center of the Table of Elements Non-metals: found on the
right side of the Table of Elements Metalloids: found along
the stair-step line Synthetic: made in the
laboratory and not yet found in nature – many of the Actinide and Lanthanide series and very large # elements.
Diatomic Elements – Nonmetals that come as molecules
7 Elements are di- (2) atomic (atoms) The easy way to remember them is by the name
Br2 I2 N2 Cl2 H2 O2 F2
When they are broken down, the pieces have completely different properties than the compound.
Compound- Made of molecules- two or more atoms
can be separated into simpler substances only by chemical means.Molecules are the smallest particle of a compound that retains its properties and it is composed of 2 or more atoms.
Compounds
SYMBOLS AND FORMULASEach element is
represented by one- or two- letter chemical symbol. The symbols for most
elements consist of the first one or two letters of the element’s name.
A chemical formula is a combination of symbols that represents the composition of a compound.A formula shows two things:
1.The elements present in the compound2. The relative number of atoms of each element in the compound.
Example H2O
Formulas often contain numerals to indicate the ratio of elements in the compound.
The numbers used in the formula are called subscripts.
PHASES OF MATTER Gases
Gas particles are independent of each other and move in a straight line.Change in
direction occurs only with collisions.Gases assume the
shape and volume of their container.
Phases of MatterLiquids
Liquid particles do not act independently of each other - motion is limited.Liquid particle slips by each other because the particles have vibratory type of motion.The particles still travel in a straight-line path between collision.Liquids have definitive volume and assume the shape of their container.
Phases of MatterSolids
Solid particles occupy a regularly fixed position in relation to surrounding particles.Solid particle appears to vibrate around a fixed point.Particles are closely packed and travel a distance equal to only a fraction of their diameter before colliding.Solid particles are arranged in a definite pattern and have definite shape and volume.
PHASES OF MATTERPlasma
Plasma is a high energy electrically charged mixture of ions and electrons.Particles that have been ionized
(charged)There exist at extremely high
temperatures.Exist at naturally (stars) or man-
made (neon signs).While plasma is the most abundant
phase of matter in the universe, on earth it only occurs in a few limited places.
Bose-Einstein condensate Extremely dense form of matter. Particle motion slowed down by
decreasing temperature to cease motion. Consider to be super unexcited and
super cold (approaching absolute zero, – 273K)
PHASE CHANGESPhysical changes are changes in the form of
a substance but not in the substance.The substance remains the same after the
change but appears different. (Phase change)Physical changes can be reversible.Examples of phase changes
MeltingFreezingBoiling/Vaporization CondensationEvaporationSublimation
PHYSICAL PROPERTIES PHYSICAL PROPERTIES ARE TWO TYPES:EXTENSIVE PROPERTIES & INTENSIVE PROPERTIES.
Extensive properties are properties that depend on the amount of matter present.MassLengthVolume
Intensive properties are used to identify a substance.
DensityColorCrystalline shapeMelting and Boiling point
Refractive index
CHEMICAL REACTIONS CHANGING REACTANTS TO PRODUCTS
Chemical changes are changes in which a new substance with different characteristics from the original substance is produced.Chemical changes
are not reversible.
There are several examples of chemical changesBurningDigestionFermentingCorrosion
Chemical Reactions Changing Reactants to Products
Chemical properties describe the reaction of a substance with other material or the reaction within the substance itself. Lack of chemical reactivity is also important.
The evidence of a chemical reaction Color ChangeFormation of a gasTemperatures change.OdorPrecipitate
CONSERVATION OF MASSDuring a chemical reaction, the quantity of matter is unchanged. The mass of products is always equal to the mass of reactants. The same can be said for physical changes.This is known as the Law of Conservation of Mass. The law states that mass can neither be created nor destroyed, it is conserved. Some of the mass can be in the form of energy or a gas.
Matter
Mixture Pure Substance
ElementCompoundHeterogeneous Mixture
Homogeneous Mixture
Can be separated physically
Cannot be separated physically
Can see the parts
Cannot see the parts
Can be separated chemically
Cannot be separated
Most impure Most pure
suspension colloid
CLASSIFY THE FOLLOWING SLIDE USING THESE FIVE
CLASSIFICATIONS:- NON-MATTER
- HETEROGENEOUS MIXTURE
- HOMOGENEOUS MIXTURE- COMPOUND
- ELEMENT
HeliumHe Bronze
Cu + Sn
Electricity
SteelFe + C
WaterH2O
Cookie
AirN2 + O2 + Ar + CO2
Carbon DioxideCO2
Italian Dressing
IronFe
Salt WaterH2O + NaCl
DiamondC
Heat
Light
MercuryHg