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Introduction to Chemistry
Chemistry
The study of the composition, structure, and properties of matter, the processes that matter undergoes, and the energy changes that accompany these processes.
Branches of Chemistry
•Organic – carbon containing compounds•Inorganic – metals and anything not organic•Physical – properties / changes / energy•Analytical – identification and composition of
materials•Biochemistry – living things•Theoretical – math & computers to understand
Research & Technology
•Basic Research – for the sake of knowledge•Applied Research – to solve a problem•Technological Development – improve quality of life
Matter is anything that has mass and takes up space.
Mass is a measure of the amount of matter.
Volume is the amount of space an object occupies.
Building Blocks of Matter
•Atom – smallest unit of an element that maintains the chemical identity of that element.
•Element – pure substance that cannot be broken down into simpler, stable substances and is made of one type of atom.
•Compound – substance that can be broken down into simple stable substances. Each compound is made from the atoms of two or more elements that are chemically bonded.
Extensive Properties
Volume Mass Amount of energy
depend on the amount of matter present.
Intensive Properties
Melting Point Boiling Point Density Electrical Conductivity
do not depend on the amount of matter present.
Physical Properties
Density Color Melting point
can be observed or measured without changing the identity of a substance.
Chemical Properties
Flammability (tendency of a substance to burn in air)
Reactivity Toxicity
relate to a substance’s ability to undergo changes that transform it into a different substance.
Physical Changes
If it is still the same substance when you are done with it, it is a physical change.
Ex: Crushing, tearing, Evaporating Water (still H2O), any phase change.
Chemical Changes
If it is NOT the same substance when you are done with it, it is a chemical change.
Ex: Cooking or burning something, Rusting metal.
How Do You Know?
Chemical Change: Bubbling, color change, temperature change.
Energy is always either used or given off in any physical or chemical change.
Energy cannot be created or destroyed (Law of Conservation of Energy).
Energy
*Ask Yourself …
Has the change altered the identity of the substance?
If yes … Chemical Change If no … Physical Change
States of Matter
Solid – definite shape and definite volume.
States of Matter
Liquid – indefinite shape but definite volume – takes shape of container.
States of Matter
Gas – no definite shape or volume – expands to fill container and takes shape of container.
States of Matter
Plasma – no definite shape or volume – a high temperature state where atoms lose most of their electrons.
States of Matter
Changes in State
Changes in Matter
Mixture: A blend of two or more kinds of matter, each of which retains its own identity and properties. Can be separated.
Pure Substance: Has a fixed composition.
Classification of Matter
Compounds (Ex: water, sodium chloride, sucrose)
Elements (Ex: gold, aluminum, oxygen, chlorine)
Pure Substances
Homogeneous: same throughout
(Ex: air, stainless steel, solutions like sugar-water)
Heterogeneous: not the same throughout (Ex: granite, wood, blood)
*Mixtures
Filtration – pour liquid through paper that catches solid and lets liquid pass through.
Can only be used on a heterogeneous mixture of a liquid and a solid.
Separating Mixtures
Distillation Crystallization Chromatography
Separating Homogeneous Mixtures by……
Chromatography – solution is separated by allowing it to flow along a stationary substance.
Separating Homogeneous Mixtures
Distillation – separates by different boiling points.
Separating Homogeneous Mixtures
Crystallization – boil off or evaporate off the liquid and you are left with the solid.
*Separating Homogeneous Mixtures
Intro to Periodic Table
Metals Nonmetals Metalloids
Organizing the Squares
Groups or families – Vertical columns
Groups have similar chemical and physical properties.
Periods – Horizontal Rows
Luster - shiny Conduct Electricity & Heat Malleable – hammered
into thin sheets Ductile – drawn into wire
Properties of Metals
No Luster – not shiny Nonconductors Brittle Non-Ductile
Properties of Non-Metals
SULFURHelium
Also called semimetals Have properties of both
metals and non-metals. B, Si, Ge, As, Sb
Properties of Metalloids
Group Names
Alkali MetalsAlkaline Earth MetalsTransition MetalsHalogensNoble Gases
Inert Gases do not readily react. Are gases at room temperature.
*Noble Gases