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