UNIT 2 PHYSICAL & CHEMICAL PROPERTIES

What Is Matter?

How matter is made of Elements?

What atoms make up?

Theory Law and Hypothesis

Physical and Chemical Changes

Heterogenous and Homogenous Substances

WHAT IS CHEMISTRY?

Chemistry is the study of the structure and composition of

matter, the physical and chemical changes it undergoes,

and the energy that is exchanged

By understanding how matter interacts with itself we are

able to make compounds that help benefit the world

(medicine, fuels, clothes, soap, etc.)

WHAT IS MATTER?

Matter- Anything that takes up space and has mass

Everything is made up of matter (Rocks, Metals, Oils,

Gases, Human Body)

Matter can be found in 3 states (solid, liquid, & gas)

WHAT MATTER IS MADE OF?

Matter is made up of Elements

Element- is a substance that cannot be broken down to other substances by chemical reactions

92 naturally occurring elements

Around 24 man made elements

Each element is classified into one of 3 classes

Metal, Nonmetal, Metalloid

ELEMENTS

Elements are

represented by symbols

Carbon = C

Oxygen = O

Sodium = Na

ESSENTIAL ELEMENTS

25% of the natural elements are Essential Elements

Essential Elements- Elements that are needed for basic

everyday functions of life

Around 96% of all the elements Humans use can be broken

down into 4 Essential Elements (Carbon, Oxygen,

Hydrogen, & Nitrogen)

NAME THESE ELEMENTS:

COMPOUNDS

Compound- Consist of 2 or more different elements

combined (chemically bonded) in a fixed ratio

ATOMS

Atom- The smallest unit of matter that still retains the properties

of an element

Each element consist of a certain type of atom different from the

atoms of any other element (every type of atom is different)

Atoms make up all matter!

Law: tells us exactly what is going to happen, these are

statements that have been proven correct through

hundreds if not thousands of experiments

Theory: attempts to explain why something happens not a

proven law

Hypothesis: educated guess on whats going to happen

LAWS, THEORIES, & HYPOTHESES

LAWS

Law of Conservation of matter/mass:

Mass cannot be created or destroyed in ordinary

chemical or physical processes

Law of Conservation of Energy:

Energy is cannot be created or destroyed in ordinary

chemical or physical processes

ENERGY AND INERTIA

Inertia: The tendency of a body in motions to resist change

in either direction or velocity when acted on by another

force

Energy: the capacity to do work or transfer heat

If it moves something, resist movement, heats up or cools

down energy is involved

TYPES OF ENERGY

Potential energy: this type of energy is the energy of

position

Gravitational Potential Energy

Kinetic energy: the energy of motion

Peeling out of tires (heat is exerted)

MASS VS WEIGHT

The amount of matter

present

Does not change with

position

Measured by the amount of

gravitational force on an

object

varies from position due to

gravitation forces (think of a

man on the moon)

Weight: Mass:

HOMOGENEOUS & HETEROGENEOUS

All matter can be classified into 2 categories- Homogeneous and Heterogeneous

Homogeneous: one phase throughout or completely uniform

Looks the same throughout (water)

Heterogenous: matter made up of more then one phase

Visible differences throughout (Chocolate Chip Cookie Dough)

CLASSIFY HOMOGENEOUS OR HETEROGENOUS :

Bird Seed

Silver

Water

Salsa

Cherry Kool-Aid

Heterogenous

Homogenous

Homogenous

Heterogenous

Homogenous

HOMOGENOUS SUBSTANCES

Element (simplest unit matter can be broken down to)

Compound (combination of elements)

Solution: a uniform mix of 2 or more substance which are

not chemically bonded therefore the components retain its

original identity and properties

SOLUTIONS

Component which “disappears” whose phase is changed

This only happens if both components are in the same physical state or the solute is in lesser quantity the the solvent

Think of Salt in water

Component which remains

unchanged

This only happens if both

components are in the same

phase or if the solvent is in

greater quantity

Solvent Solute

EXAMPLE 2-2:

Aluminum Chloride is a white crystal and alcohol is a clear liquid. When mixed, a clear liquid solution results. If 100 grams of aluminum chloride is mixed with 95 grams of alcohol, what is the Solvent?

Alcohol

Even though there was more aluminum chloride a clear liquid was formed. This bit of information gave you your answer. Alcohol retained its properties and remained unchanged so it’s the solvent.

HETEROGENEOUS SUBSTANCES

Always Mixtures but not uniform compositions

there is more then one phase present in the mixture

95% of mixtures are Homogeneous

CLASSIFYING MATTER

You must always have 2 words to classifying types of

matter

Homogenous or Heterogenous

Element, Compound, Solutions, Mixture

REMINDERS

Element-is a substance that cannot be broken down to other substances by chemical reaction

Compounds consist of 2 or more different elements combined (chemically bonded) in a fixed ratio

Solution- are uniform mix of 2 or more substances one of which is dissolved into the other

Mixtures- any substance that has a uniform and unchanging composition that is considered to be pure.

CLASSIFY THE FOLLOWING SUBSTANCES

Birdseed

Cooking Oil

Water (H2O)

Silver

Salsa

Heterogenous Mixture

Homogenous Solution

Homogenous

Compound

Homogenous Element

Heterogenous Mixture

PROPERTIES OF MATTER

Physical Properties- describes the substance by itself

Intensive properties- Properties that do not change with the amount of it (density, melting point, boiling point, color)

Extensive properties- depends on the amount of matter present (mass, volume, length, heat)

Chemical Properties- describe how a substance reacts to something else (does it burn?)

TYPES OF CHANGES IN MATTER

Physical Change- matter will change its physical state but

not composition often reversible

Chemical Changes- A new substance is being formed

these are typically not reversible

PHYSICAL CHANGES

A physical change can have a compound or solution

changing its physical characteristics without changing the

chemical makeup of the compound or solution

Ice melting changes solid to a liquid but its still H2O

Melting, Vaporization, Condensation, Freezing,

Sublimation (solid to vapor), deposition (vapor to a solid)

CHEMICAL CHANGES

A new substance is being formed

Think of burning, digestion, rusting

Clues that can indicate a chemical change

color change

texture change

Gas is produced

mass change

Precipitation is formed

SOLIDS, LIQUIDS, & GASES

States of Matter depend on the freedom of

movement of atoms in that state

Solids have a definite shape and volume their

atoms are tightly packed in together

Liquids have a definite volume but not shapes

the atoms have some freedom to move around

Gases have neither a definite shape or volume

this allows them to have freely flowing atoms

Matter makes up Everything

Matter is made up of Elements

Atoms make up elements and compounds

Scientific Theories, Laws, and Hypothesizes

The difference between mixtures and solutions are

Heterogenous and Homogenous Substances

Physical and Chemical Changes

Difference between Solid, Liquids, and Gases