Welcome to Chemistry!!
What is Chemistry?
• The study of all substances – composition, structure and properties - and the changes that they can undergo.
• Chemistry is everything!!
Branches of Chemistry
CHEMISTRY
Organic Inorganic Biological PhysicalAnalytical Theoretical
Types of Research• Basic – for the sake of increasing
knowledge
• Applied – generally used to solve a problem
• Technological Development – production/use of products to improve quality of life
What is Matter?
• Matter is anything that has mass and takes up space.
• Mass is the amount of matter in an object.
Building Blocks of Matter
• Atom – smallest unit of an element that maintains the chemical identity of that element
• Element – pure substance, all one type of atom
• Compound – made of atoms of two or more elements chemically bonded
Properties
• Extensive – depend on amount of matter– Ex: volume, mass
• Intensive – do not depend on amount of matter– Ex: melting and boiling point, density
Physical Properties
• Physical Property- a property that can be observed and measured without changing the substance.
• Physical change - changes appearances, without changing the composition.
States of Matter
• Solid- has definite shape and definite volume.
• Liquid- definite volume but takes the shape of its container (flows).
• Gas- a substance without definite volume or shape and can flow.
• Plasma- high temperature state of matter where atoms lose most of their electrons
Solid
Liquid
Gas
Definite Volume?
YES
YES
NO
Definite Shape?
YES
NO
NO
Temp. increase
Small Expans.
Small Expans.
Large Expans.
Com-pressible?
NO
NO
YES
States of Matter
Solid Liquid Gas
Melt Evaporate
CondenseFreeze
Chemical Properties• Chemical Property- a property that can
only be observed by changing the type of substance.
• Examples: Flammability, decomposition, reactivity
• Chemical change/reaction - a change where a new form of matter is formed.
Chemical Reactions
• Reactants: substances that react
• Products: substances that are formed
Paper + Oxygen + Fire Ash + Smoke
Classification of Matter
MATTER
Can it be separated?
Mixtures Pure Substances
Is composition uniform? Can it be decomposed by ordinary chemical means?
Homogeneous Mixture
Air, sugar water, stainless steel
Heterogeneous Mixture
Granite, wood, blood
Compounds
Water, sodium chloride
Elements
Gold, aluminum
yes
yesyes
no
nono
Mixtures• Blend of two or more kinds of matter, each
of which retains its own identity and properties
• Heterogeneous- mixture is not the same from place to place.– Chocolate chip cookie, gravel, soil.– VISIBLE particles
• Homogeneous- same composition throughout. aka: solution– Kool-aid, air.– NON-VISIBLE particles
Separating Mixtures
• Heterogeneous mixtures use filtration or vaporization
• Homogeneous CANNOT use filtration
- use distillation, crystallization and chromatography
Distillation
Chromatography
Pure Substances
• Either Compounds or Elements
• Every sample has exactly same characteristic properties (mixtures depend on components)
• Every sample has exactly same composition ALWAYS
Which is it?
ElementCompoundMixture
MATTER
Can it be separated?
Mixtures Pure Substances
Is composition uniform? Can it be decomposed by ordinary chemical means?
Homogeneous Mixture
Air, sugar water, stainless steel
Heterogeneous Mixture
Granite, wood, blood
Compounds
Water, sodium chloride
Elements
Gold, aluminum
yes
yesyes
no
nono
Elements
Periodic Table
• Elements are organized into groups based on similar chemical properties
• Vertical columns – Groups/Families
• Horizontal rows – Periods
• 2 rows on the bottom– Lanthanide series– Actinide series
Types of Elements
Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 22 Aug. 2004
Metals
Metals
• Conduct electricity and heat
• Malleable: hammered into sheets
• Ductile: drawn into wire
• Tensile strength: resist breaking when pulled
Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 22 Aug. 2004
Nonmetals
Mr. Green. Mr. Green’s Homepage. 10 Sept. 2003. http://www.tvgreen.com/index.htm. 22 Aug. 2004
Metalloids
Types of Elements
• Nonmetals– Poor conductor of heat and electricity– Solids are brittle
• Metalloid– Share characteristics of metals and
nonmetals– semiconductors
• Noble Gases – relatively unreactive