What is Chemistry?

Unit 1 – Introduction to Chemistry

What is Chemistry?

Chemistry is the study of matter

What is matter? Matter is anything that has mass and

volume

What is mass and volume?

Mass: The amount of matter in an object How much an object weighs

Volume: The amount of space an object occupies

Are mass and weight the same thing?

Balance Scale

Gravity independent Gravity dependent

Anywhere Changes with gravity

Now that we know what matter is…

Can you think of 5 examples of matter?

Can you think of the 4 examples of non-matter?

Brainstorm with your partner please.

Matter – further break down

What is the building block of matter? Atom – the basic unit of matter

What is it called when two or more atoms are combined? Molecule – two or more atoms that behave as a

unit They are chemically bonded

Classification of Matter (pg. 3)

Matter can be classified into two major groups: Pure Substance Mixture

Pure Substance

Definition: Made up of only one kind of atom or

molecule Example: carbon

Mixture

Definition: Matter that is made up of more than one

kind of atom or molecule. Two or more pure substances mixed Example: salt water

Not chemically bonded Can be separated by physical means

Further classification:

Pure substance and mixture can be further classified Pure substance can be further classified

into an element or compound Mixture can be further classified into a

homogeneous or heterogeneous mixture

Element

Definition: A pure substance that is made of only a

single kind of atom Cannot be broken down Found on periodic table Most basic form of matter

Example: Copper

Compound

Definition: A pure substance that is made of more

than one kind of atom 2 or more elements chmically bonded

Example: water

Homogeneous mixture

Definition: A mixture that has a uniform composition Example: Soda

Heterogeneous mixture

Definition: A mixture that is non-uniform

It has layers Example: muddy water

homework

Read 1-1 Answer ?s 1-10 on page 23 (write down

the question)

States of matter (page 3)

Also called the phases of matter

Solid Liquid Gas

Solid Has both a definite shape and definite

volume At the molecular level, the particles that

make up the solid are close together and many times are locked into a very regular framework called a crystal lattice The atoms and molecules are held tightly

in a rigid structure but vibrate slightly about their fixed positions

Cannot compress

Liquid Definite volume, but variable shape Cannot compress It conforms to the container in which it is

placed Particles in the liquid are not held together in

a rigid manner that is characteristic of solids However, the distances between the particles

are constant on average Particles are moving much more than in the

solid There are usually clumps of particles moving

relatively freely among other clumps

Gas

No fixed shape or volume Expand to fill any container they occupy The particles move rapidly with respect

to each other and act basically independently of each other

Plasma

Sea of ions Example: Sun

Changing phase

Solid

melting

freezing Sublimation Liquid

boiling

condensing Gas

Deposition

States of matter

Identified using the following: If an item is a solid, it is followed by (s)

Ice = H2O (s)

If an item is a liquid, it is followed by (l) Tap water = H2O (l)

If an item is a gas, it is followed by (g) Steam = H2O (g)

Methods of separating mixtures

Separate by physical means Substances are not altered chemically

Examples: filtration, evaporation, centrifuge, decant, chromatography, distillation, density

Identification of matter

Matter can be identified by two types of properties Physical Chemical

State Functions

Intensive property Any property of a system that does not depend on

how the process Density Specific heat

Extensive Property depends on amount of matter

VolumePressureTemperature Internal Energy

Physical properties

Can be observed without changing the composition of the matter

Appearance of physical state changes, but not the chemical composition shape Examples: color, volume, shape, mass,

length, odor, solubility, density, specific heat, melting point and boiling point

Chemical properties

Observed only when substances interact with one another

The original substance changes into something else

Different chemical substances are formed

Breaks chemical bonds

Examples of Chemical Properties

•Rust

•Burning

•Fruit ripening

•Baking

•Souring

Physical vs. Chemical Changes

Physical – original substance still exists Only the form or physical appearance changes

Example: cutting in half writing on paper changing the phase of matter

Physical vs. Chemical Changes

Chemical - produces one or more new substances Observed only when substances interact with

one another The original substance changes into

something else Example:

bubbles (production of a gas) change in color forms a precipitate (solid) produces heat or light (explosions)