8th Grade FCAT Review Physical Science: Matter

•Atoms are the smallest units of matter (for now). •All matter is made up of atoms. •The different ways atoms combine contribute to the diversity of all living and nonliving things. • Trees, Dogs, DNA, Rocks, Metals, Water,

People, etc. •When atoms combine in different ways, they form compounds. • Certain atom combinations make

certain compounds.

Atomic Theory

Atomic Structure Nucleus has most of the mass

Protons

- positive electric charge

- = Atomic (top) number

- how many determines what

element

Neutrons

- no electric charge

- = AMU (bottom) – Atomic (top)

Numbers

Electron

- negative electric charge

- mass is almost 0

- The electron number of neutral atoms is = to the proton number.

- flies around the nucleus at almost the speed of light

Phases of Matter

Matter is anything that has mass and takes

up space (volume).

All matter is made up of atoms.

The phase/state that the matter is in

depends on how the atoms are behaving.

Based upon particle arrangement

Based upon energy of particles

Based upon distance between particles

Solids

Definite SHAPE, VOLUME, and

MASS

Atoms of solids are tightly packed

together.

Atoms of solids have slight

vibrating movement.

– Low Kinetic energy

To change a solid you can add

heat/thermal/kinetic energy

– Melt (solid to liquid)

– Sublimation (solid to gas)

Liquids

Definite VOLUME and MASS.

No definite SHAPE

Atoms of liquids are loosely

held together.

Atoms of liquids have fluid movement.

– Mid-level Kinetic energy

To change a liquid you can add or remove

heat/thermal/kinetic energy

– Adding energy - Boiling/ evaporation (liquid to gas)

– Removing energy – Freezing (Liquid to solid)

Gases Definite Mass. No definite

SHAPE or VOLUME.

Atoms of gases bounce off

each other and expand to fill a

given space.

Atoms of gases have very

rapid continuous movement.

– High Kinetic energy

To change a gas you can add or remove

heat/thermal/kinetic energy

– Adding energy – change to plasma (superheated

gas)

– Removing energy – Condensation (Gas to Liquid)

Organization of Matter – The Periodic Table

• As you move from left to right, the elements go from being highly reactive/unstable to being nonreactive/stable.

• Alkali Metals (Group 1) – most reactive and unstable

• The Noble gases (Group 18)- stable and nonreactive

• Each period begins with an element that has 1 valence electron and ends with an element that has 8 valence electrons.

• This repeating pattern means that the elements within a group always have the same number of valence electrons.

• As a result, the elements in each group have similar properties.

Classification of Matter

Atom = all matter

Molecule = multiple atoms

Compounds = multiple same molecules

Mixture = Multiple different molecules

Homogeneous: looks the same, can’t easily separate (solution)

Heterogeneous: looks different, can separate

Solutions

Some homogeneous mixtures are made of chemicals that are able to dissolve. They are soluble.

In a solution the smallest portion is the solute: Salt in saltwater

In a solution the larger portion is the solvent: Water in saltwater

A solution with a little solute is dilute: 1 drop on Mio in a bottle of water

A solution with a lot of solute is concentrated: 20 drops of Mio in a bottle of water

Acid and Base Solutions Acid – low pH (0-6), makes H3O (hydronium) in

solution

Base – high pH (8-14), makes OH (hydroxide) in solution

Salt – When an acid and a base combine and neutralize, pH around 7

pH scale- KNOW HOW TO READ IT!!!! Basic

WHY ARE CHEMICAL AND PHYSICAL PROPERTIES USEFUL?

•Harness, texture, flammability, and color are all examples of properties of matter.

•Characteristic properties of matter can be used to identify unknown substances.

•Density, magnetism, melting and boiling points, and the ability to conduct heat and electricity are some properties that hold true, regardless of the amount of the sample.

PHYSIVAL PROPERTIES OF METALS •Luster-shiny and reflective

•Malleable- a material that can be hammered or rolled into flat sheets or other shapes (aka bendable).

•Ductile- material that can be pulled out, or drawn, into long wires.

•Thermal conductivity- ability of an object to transfer heat.

•Electrical conductivity- ability to carry electric current.

PHYSICAL PROPERTIES OF NONMETALS •Most nonmetal are poor conductors of electric current and heat.

•Solid nonmetals tend to be dull and brittle.

•Many nonmetals are gases at room temp.

CHEMICAL PROPERTIES •Ability to corrode, ability to rust, ability to decompose, cooking, baking, burning.

PHYSICAL CHANGE

• Any change that al ters the form or appearance of a substance but does not change into another substance.

• E.g. Cutting Paper

CHEMICAL CHANGE

• A change in matter that produces one or more new substances is a chemical change.

• Burning and rusting are both chemical changes.

• E.g. Burning Paper

• The substance that goes through the chemical change = reactant

• The new substance that forms = product

Physical and Chemical Changes

Physical vs. Chemical Properties

Which properties shown above are physical

properties? Why are they considered

physical?

Physical vs Chemical Changes

Which images above are examples of

physical changes and which are

chemical changes? How do you know? SC.8.P.9.2

Laws of Conservation of Mass

MATTER IS NEVER CREATED NORDESTROYED

•When chemical and physical changed occur in chemistry, even though it may appear that way, the mass going into the reaction is equal to the mass coming out.

• The chemical changes may make this hard to see. Ex. Burning wood, corrosion of metals, etc.

•Recall that Earth is a system made up of the biosphere, geosphere, hydrosphere, and atmosphere.

•According to the conservation laws, the total amount of energy in the Earth system stays constant.

•When the organisms die, their matter is returned to the soil, the atmosphere, or other parts of the Earth system.

•Then the cycle starts again with other organisms.

Sample Question

Susie is completing the table shown below:

Column A Column B

Na NaCl

Ca CaCl2

Fe Fe2O3

Pb PbN6

What are the best headings for columns A and B? A. Column A: Atoms Column B: Mixtures B. Column A: Molecules Column B: Atoms C. Column A: Elements Column B: Compounds D. Column A: Atoms Column B: Elements

Sample Question

After a particularly rainy spring, Kristen and Amanda could no longer bear to stay indoors and, with the first sign of fair weather, ventured outside for a walk through the park. As they passed the jungle gym, they noticed that the iron monkey bars looked different. What can you do to pure, solid iron to chemically change it?

A. cut it

B. melt it

C. bend it

D. oxidize it

Sample Question

The elements iron (Fe), copper (Cu), and mercury (Hg) are classified as metals. Which physical property of metals do they all share?

A. They are all magnetic

B. They are all a shiny, reddish color.

C. They all have the same melting points.

D. They all have thermal and electrical conductivity.

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