Matter

Vocabulary!Matter: anything that has mass and takes

up space.

Mass: measure of the amount of matter in an object. Constant. Measured in Kg

Volume: amount of space an object takes up.

Weight: measure of the gravitational force on an object. Changes. Measured in newtons.

Density: ratio of the mass of a substance to the volume of the

substance. D=M V

Mass vs Weight

• Transparency in chem folder

So then, what’s density?

• It’s the amount of mass in a given volume

Important stuff Density = Mass Volume

Water has a density of 1.0

So if the density is lower that that, it floats

If the density is greater than 1.0, it sinks!

States of Matter

Physical states in which a substancecan exist.

Fill in the chart with + or -

Shape Volume Solid Liquid

Gas

• Solid-constant shape and volume

• Liquid-no shape, has a constant volume

takes on shape of container

• Gas-no shape or volume.

takes on shape of container, but FILLS it

Solid

Particles are close to each other and vibrating

Liquid

Particles move faster, and away from each other

Why is this bug not sinking?

Surface tension: force that acts on the particles on the surface of a liquid.

Gas

• Particles travel away from each other VERY FAST

• They push on the container wall, causing PRESSURE

• Volume increases with heat, decreases with cold

States of Matter

Change of state: change of a substance from one physical state to

another. This change uses or loses energy

Melting: change of state from solid to liquid. Energy added.

Freezing: change of state from liquid to solid. Energy removed.

Evaporation: change of a substance from liquid to gas at the surface. Boiling: change of a liquid to a gas throughout the substance.

Condensation: change of a gas to a liquid.

Changing States

melting evaporation

What’s it called when water goes from a gas to a liquid?

• Solid->Liquid->Gas

• Uses Energy

• Gas->Liquid->Solid

• Gives off Energy

States of Matter

Chemical vs Physical Properties

Physical properties: characteristics that can be observed without changing the substance. Do not change with the amount

Example: color and density

Chemical properties: characteristics that describe a substance’s ability to change.

Baking soda can react with vinegar

Chemical vs. Physical Changes

Physical change: substance is not altered chemically, but changed to another state. or separated or combined.

Chemical change: substance is altered chemically and displays different physical and chemical properties.

Chemical or Physical Property?

1. Water boils at 100 degrees C

2. Diamonds are able to cut glass

3. Iron rusts in a damp environment

4. Salt is dissolved in water

5. Dry ice sublimes at room temperature

Chemical or Physical Property?

Gasoline burns in the presence of oxygen

Bromine has a red color

Hydrogen Peroxide decomposes to water and oxygen

Vinegar will react with baking soda

Aluminum has a low density

Chemical or Physical Property?

Wood is flammable

Ammonia is a gas at room temperature

Yeast uses sugar to form carbon dioxide and ethanol

Water can be separated by electrolysis into hydrogen and oxygen

Review• A Physical property is one you can see or

measure• A Chemical property is how an element

behaves in a reaction

• A Physical change is a change of state—the element is the same element in the end

• In a Chemical change, the substance changes into a different substance

Vocabulary

element-a substance that cannot be broken down

compound-combination of different elements

atom-smallest indivisible particle of matter

molecule-2 or more atoms bonded together O2

Fe

NaCl

Compounds

Compound Formula Elements

• Water H2O hydrogen, oxygen

• Carbon Dioxide CO2 carbon, oxygen

• Vinegar CH3COOH carbon, hydrogen,

oxygen

Atoms

Nucleus—contains most of the mass protons and neutrons

Electrons-orbit in a fast moving cloud

Atomic Nuclei

Protons—positive charge

Number of protons = Atomic Number

Neutrons—no electrical charge

Neutrons + protons = Mass Number

Electrons—negative charge

Add to Vocabulary List

Proton—positive charge. In nucleus.Neutron—no charge. In nucleus.Electron—negative charge. In cloud.

Add to Vocabulary List

• Atomic Number---number of protons

• Atomic Mass—(mass number)

number of protons + neutrons

A Variation—add to List

Isotope-atoms of the same element with different number of neutrons many are radioactive

Carbon 14—used to date fossils

Atoms with the same number of protons (+)

and electrons(-) are neutral

Remove an electron, and it becomes POSITIVE: a positively charged ion

Add an electron, and it becomes NEGATIVE: a negatively charged ion

Your turn!

• Turn to page 521 in your science textbook.

• Math Focus

• Continue with Atomic Charges

Electron Energy Levels

• Remember the 2-8 Rule!

Carbon

Atomic Number 6

Shells are 2--4

The number of electrons in the outer shell determines the behavior!

ElectronsElements with one electron in the outer

shell are very reactive

Sodium

Elements with 7 electrons are also! Chloride

Elements with 8 electrons in their outer shell are very stable

noble gases (inert)

Oxygen has an atomic number of 8. What is its configuration?

2-8-1 2-8-2

2-8 makes a happy atom!Remember

2-8 makes a happy atom!

2-6 Wants 2 2-7 Wants 1

Remember

Look at the Periodic Table

Ionic Bond

Sodium (Na) donates one electron to Fluoride (Fl)

NaFl

Covalent Bond

• Atoms SHARE electrons

• Stronger than ionic bonds

Chloride— 7 in outer shell

Hydrogen—1 in outer shell

2 electrons are shared so the shells are 8 and 2—stable!

HCl

Ionic and Covalent Bonds

• Ionic—electrons are donated

Metal with non-metal

Valence number—tendency to gain or lose

electrons

example: Na +1

• Covalent—electrons are shared

Two types

Polar and Nonpolar

Polar Covalent Bonds

• Electron sharing is NOT equal

• One end pulls HARDER

• Makes one end more negative and the

other more positive

Example: Water!

H and O atoms

Nonpolar Covalent Bonds

• Electrons are shared equally

• Entire molecule has same charge

examples: diatomic gases

H2 O2 N2