NOTES

• Matter- (stuff) Anything that has volume and

mass • Volume – (size) amount of space something

occupies

• Mass - Amount of matter in an object

Physical and Chemical Properties

• It’s all about identity!

– Property – a unique feature or characteristic– Physical property – can be observed without

changing the substance’s identity (color, density, melting point)

– Chemical property – ability to change into a new substance ( flammability, reactivity)

Examples….

SUBSTANCE

PHYSICAL PROPERTY

CHEMICAL PROPERTY

Helium Less dense than air

Nonflammable

Wood Grainy texture Flammable

Vinegar Clear liquidReacts with baking soda

Physical and Chemical Changes

• Its STILL all about identity!

• Physical changes – don’t change the identity of the substance (ripping, mixing).

• Chemical changes – form completely different substances (burning, reacting)!

Examples….

PHYSICAL CHANGE

CHEMICAL CHANGE

Freezing water Baking a cake

Cutting your hairReacting baking soda & vinegar

Crushing a can Milk turning sour

Pure Substances vs.

Mixtures

Pure substances –

– Are made up of ONE type of particle –all of the particles are the same!

– They cannot be broken down into anything simpler by physical means.

– Ex. oxygen, water, etc.

Mixtures• Are made up of two or more types of pure

substances - physically combined

• Mixtures can be separated by ordinary physical means.- If you pick the onions out of your salad, you are

“physically separating” a mixture.- Like salt water – if you evaporate the water, the salt

is left behind!

Four States of Matter

DEFINITE SHAPE?

DEFINITE VOLUME?

MOLECULAR MOTION

SOLIDS YES YES MOVING SLOWLY

LIQUIDS NO YES MOVING FASTER

GASES NO NO MOVING VERY FAST

PLASMAS NO NO MOVING VERY FAST

Crystalline Solids

• Have a fixed, regularly repeating arrangement. – Ice, salt, and sugar

are crystalline solids

Amorphous Solids

• Are made of particles that are jumbled together without a repeating pattern– Rubber, jello, and the eraser on your pencil

are all amorphous solids

Plasmas• These are “Super Gases”

– When lots of energy moves through a gas, it becomes a plasma

• Like fire, lightning and the Northern Lights

Aurora over Alaska

(Strang, 2005)

Molecular Motion

• Solid: The particles just sit in place and vibrate

• Liquid: The particles overcome some of their attraction and slide past each other – like the ball-pit in the McDonalds playground

• Gas: The particles have almost no attraction and move very quickly – like a room full of superballs bouncing all over the place!

• http://www.harcourtschool.com/activity/states_of_matter/index.html

• http://phet.colorado.edu/en/simulation/states-of-matter-basics

Motion of plasmas

• Particles are extremely hot and slam into each other, breaking into smaller pieces called ions.

Changes of State – freezing and melting

• Solid liquid = Melting

• Liquid solid = freezing

Freezing

Melting

Changes of State – Vaporizing and Condensing

• Gas Liquid = Condensing

• Liquid Gas = Vaporizing

• Solid Gas = Subliming (dry ice)

Condensing

Vaporizing

Elements, Compounds, and

Mixtures

THREE TYPES OF ELEMENTS

METALS NONMETALS METALLOIDS

SHINY DULL SHINY AND DULL

CONDUCT HEAT & ELECTRICITY WELL

POOR CONDUCTORS OF HEAT & ELECTRICITY

“SEMICONDUCTORS”CONDUCTIVITY VARIES

MALLEABLE AND DUCTILE

BRITTLE AND UNMALLEABLE

SOMEWHAT MALLEABLEAND DUCTILE

LEAD, SILVER, & IRON SULFUR & NEON BORON & ARSENIC

An element is a pure substance that cannot be separated into simpler substances by physical or

chemical means

The Periodic Table

• A compound is a pure substance composed of 2 or more elements that are chemically combined.

• Compounds can be broken down into elements or simpler compounds through chemical changes.

COMPOUNDS

• Solutions – “Best Mixed” mixtures– Look like only one substance – very well

mixed– Air, salt water, kool-aid– Alloys are metallic solutions

• Steel (alloy of carbon and iron) • Brass (alloy of copper and zinc)

• In solutions, the solute is the substance that is dissolved, and the solvent is the substance in which the solute is dissolved.

• Solute – Least amount of material in a solution

• Solvent – Greatest amount of material in a solution

• In salt water, salt is the solute and water is the solvent.

• Water is known as the universal solvent

Water is the solvent

Salt is the solute

Salt Water is the solution

• Heat – thermal energy that is transferred from one substance to another.

• Thermal energy – comes from kinetic energy of individual atoms

• Kinetic energy- energy of an object because of its motion.– The faster particles move, the more kinetic

energy they have.

HEAT

TEMPERATURE

• Temperature – a measurement of hot or cold that depends on the thermal energy in a material

• Fahrenheit scale – water freezes at 32° and boils at 212 °

• Celsius scale – water freezes at 0° and boils at 100°

Conservation of Energy

•Energy never gets destroyed, it just changes into another type of energy.

HEAT

Particle

Heat energy is transformed into kinetic energy, making particles move faster

More heat = greater motion!

• The particles in ice have low kinetic energy. They are not moving around much.

Particle Particle Particle

Particle Particle Particle

Particle Particle Particle

HEAT

• But if some heat is added, the particles move a lot more and can break away from each other – forming a liquid!

• If the liquid gains enough heat energy, the particles can have enough kinetic energy to escape the surface.

Particle Particle Particle

Particle Particle Particle

Particle Particle Particle

HEAT

ENDOTHERMIC & EXOTHERMIC

• An exothermic reaction releases energy– Energy is removed (ex: burning)

• An endothermic reaction absorbs energy– Energy is added (ex: photosynthesis)

ENERGY

ENERGY

Change of State

• In a change of state, the energy of a substance changes.

CHANGE OF STATE DIRECTIONENDOTHERMIC OR

EXOTHERMIC?

MELTING SOLID LIQUID ENDOTHERMIC

FREEZING LIQUID SOLID EXOTHERMIC

VAPORIZATION LIQUID GAS ENDOTHERMIC

CONDENSATION GAS LIQUID EXOTHERMIC

SUBLIMATION SOLID GAS ENDOTHERMIC