Welcome to Chemistry

1.1 What is Chemistry?

Chemistry: the study of the composition, structure, and propertiesof matter, the processes that matter undergoes, and the energy

changes that accompany these processes

Speaking of which: what are we made of?Lots of stuff- carbon, oxygen, hydrogen, sulfur, phosphorous, iron, nitrogen,

to name just a few. The human body is composed of many hundreds of millions of chemical compounds and substances, each just a differing arrangement of elements

from the periodic table.

But where do these things come from?All of the elements come from the stars, and were made many billions of years ago

through the coagulation of interstellar dust.

How are the elements formed?In a process called fusion, but we’ll get to that later.

Branches of ChemistryThere are several areas of study and research in chemistry which often

overlap with one another. So put on your fun hats, here we go:

1. Organic Chemistry: the study of most carbon-containing compounds

(more on this later as we will begin organic at the end of the year)

2. Inorganic Chemistry: the study of (duh) non-organic substances which have

organic fragments bonded to metals (organometallics)

3. Physical Chemistry; the study of the properties and changes of matter and their

relation to energy.

4. Analytical Chemistry: the ID of the components and compounds of materials.

5. Biochemistry: the study of substances and processes occuring in living things.

6. Theoretical Chemistry: the use of mathematics and computers to understand

the principles behind observed chemical behavior and to design and

predict the behavior of new chemical compounds.

Chemistry

organicchemistry

inorganicchemistry

analyticalchemistry

physicalchemistry

bio-chemistry

1.2 Matter and It’s Properties

Matter anything that has mass and takes up space (volume)and so…

Mass measure of the amount of matter.

Atom: smallest unit of an element that

maintains the chemical identity of

that element.

Examples?

A carbon atom.

1.2 Matter and It’s Properties

Element: a pure substance that cannot be broken down into

simpler, stable substances and is made up of one type

of atom.

Examples?

The element carbon.

For a complete list of elements, where should we look?

More on this later.

1.2 Matter and It’s Properties

Compound: a substance that can be broken down into simple,

stable substances. Each compound is made from atoms

of two or more elements that are chemically bonded.

Examples?

1.2 Matter and It’s Properties

Properties and Changes in MatterEvery substance has characteristic properties.

Properties are either Extensive or Intensive

Extensive Properties: depend on the amount of matter present.Examples: mass, volume, amt. of energy

Intensive Properties: do not depend on the amount of matter present.Examples: melting point, boiling point, density.

1.2 Matter and It’s Properties

Physical Properties and Physical Changes

Physical Property: a characteristic that can be observed or measured

without changing the identity of the substance.

Examples:

Boiling point (temp. substance goes from liquid to gas)

Melting point (temp. substance goes from solid to liquid)

Freezing point (temp. substance goes from liquid to solid)

Condensation point (temp. substance goes from gas to liquid)

By the way, what is the boiling point of water? Freezing point?

The melting point? Condensation point?

1.2 Matter and It’s Properties

Physical Properties and Physical Changes

Physical Change: a change in substance that does not involve a change in identity of the substance.

Examples:

Grinding, cutting, melting, and boiling a material.

1.2 Matter and It’s Properties

Chemical Properties and Chemical Changes

Chemical Property: a substances ability to undergo changes that

that transform it into different substances.

Examples:

Rusting material-

Iron + Oxygen (g) Iron oxide (rust)

(before)

(after)

Quick Review!Fill in the blanks with any of the new terms you just learned …

• I am an astronaut going to the moon and I’m bringing a scale with me. In space, I will stand on the scale and find that my _______ will be the same but my ______ will have changed.

• The graphite in my pencil is only made up of carbon, therefore it is an ________. The rest of my pencil is made up of several things, which makes it more like a _________.

• Water always freezes at 0°C. This is a _______ property (hint: there are two correct answers!)

• Cutting a piece of paper in half gives me two smaller pieces of paper. Each piece is still has the same chemical characteristics but has less mass. This is called a _______ change.

Change of State:Physical change of substance from one state to another.

Solid: matter in this state has a definite volume and shape.

Liquid: matter in this state has definite volume but indefinite shape.

Gas: matter in this state has neither definite volume or shape.

Change of State:Physical change of substance from one state to another.

An important 4th state of matter is something called

Plasma: high temperature physical state of matter in which atoms

lose most of their electrons.

Change of Phase:

When a substance goes from one form to

another, (almost) always in the same order.

solid liquid gas

This goes for all substances, remember.

Now, some terms.

HEAT HEAT

- HEAT - HEAT

Change of Phase (for water):

solid liquid gasMELTING BOILING

FREEZING CONDENSING

0ºC 100ºC

melting/freezing point boiling/condensation point

(ice) (steam)(water)

Quick Review!• Fill in the blanks with any of the new terms

you just learned …• There are three main phases of matter, they are _____,

______, and ______.

• When the ice cube in my drink melts, it is considered a _____________.

• I will make Ms. T so proud by NEVER forgetting that the freezing/melting point of water is _____ and the boiling/condensation point is _____.

• When iron combines with oxygen, iron oxide, or rust, is produced. This is a ________. Iron’s ability to undergo this reaction is called a _________.

Development of the Periodic TableThe modern periodic table of elements is mostly the work of Russian chemist

Dmitri Mendeleev (1834-1907). It was set up in such a way so group elements

in columns according to their properties, but also put them in ascending order

according to their atomic number. Let’s observe:

The vertical columns are called groups; the horizontal rows are called periods.

Periodic Law: when elements are arranged in order of increasing atomic number,

there is a periodic repetition of their physical & chemical properties.

The vertical columns are called groups, or families.

There are 18 groups on the periodic table.

Groups

The horizontal rows are called periods.

Periodic Law: when elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical &

chemical properties.

Periodic Trends

Elements in the same group: physically and chemically similar

Elements in the same period: ordered in increasing size and atomic number.

Metals

Characteristics of metals: excellent conductors of heat and electricity, very reactive, usually make positive ions when dissolved in solution, mix well to make alloys.

Alkali Metals

Group 1A: Li, Na, K, Rb, Cs, Fr. Does not include hydrogen.▪ They are very reactive because of the lone electron in their outer shell.▪ Very shiny and light in weight.http://www.youtube.com/watch?v=OFG4Yr7lQzw&feature=related

http://www.youtube.com/watch?v=uqDWbknpiVk&feature=related

Alkali Earth Metals

Group 2A: Be, Mg, Ca, Sr, Ba, Ra

▪ Not as reactive as alkali metals, but form bonds very easily.

Transition Metals

Have a special electron shell arrangement where two of their outer shells

are not full. This allows them to bond to many other elements in a

variety of shapes.

Halogens

Have an outer shell that is almost full, therefore very reactive. Often bond

with metals and elements from group one (alkali metals). When an halogen

combines with another element, the resulting compound is called a halide.

Inert Gases (Noble gases)

Include: He, Ne, Ar, Kr, Xe, Rn.

Have a full outer shell and are very unreactive, hence the title “inert”.

Metalloids

Metalloids are found on the periodic table between the metals and non-metals.

Appropriately, they exhibit characteristics of both metals and non-metals.

Nonmetals

Many nonmetals are gases at room temperature: N; O; F; Cl. These are elements that are poor conductors of heat and electricity.

Words to Know• Chemical reaction – one or more substances

change into new substances [iron and oxygen form iron oxide (rust)]

• Reactants - starting substances (iron and oxygen) • Products – substances formed (iron oxide :rust)• Chemical property – ability of a substance to

undergo a chemical reaction and to form any new substance

Rusting is a chemical property of iron

1.2 Matter and It’s Properties

Chemical Properties and Chemical Changes

Chemical Change: a change in which one or more substances are converted into different substances.

Reactants Products

Reactants: the substances that react in a chemical change

Products: the substances that are formed in a chemical change.

C + O CO2

Writing Chemical Equations

• Arrows – “changes into” or “produce”

• Reactants on left side of arrow

• Products on right side of arrow

• Hydrogen + Oxygen Water

Chemical Reactions and Energy

• Energy is always absorbed or given off in a chemical reaction

• Cooking food – energy is absorbed• Burning natural gas – energy is given off• An energy change in itself is not proof that

a chemical reaction took place (Think of boiling water. Boiling is a

physical change.)

Conservation of Mass• In any physical change or chemical reaction,

mass is neither created nor destroyed• In every case, the mass of the products is equal

to the mass of the reactants• Combustion (burning) of coal: Atmospheric

oxygen combines with the coal and produces carbon dioxide gas, water vapor, and a small ash residue