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 airNonflammable Wood Grainy textureFlammable Vinegar Clear liquid Reacts 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 waterBaking a cake Cutting your hair Reacting baking soda & vinegar Crushing a canMilk 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 SOLIDSYES MOVING SLOWLY LIQUIDSNOYESMOVING FASTER GASESNO MOVING VERY FAST PLASMASNO 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! ndex.htmlhttp:// ndex.html

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 METALSNONMETALSMETALLOIDS SHINYDULLSHINY AND DULL CONDUCT HEAT & ELECTRICITY WELL POOR CONDUCTORS OF HEAT & ELECTRICITY “SEMICONDUCTORS” CONDUCTIVITY VARIES MALLEABLE AND DUCTILE BRITTLE AND UNMALLEABLE SOMEWHAT MALLEABLE AND DUCTILE LEAD, SILVER, & IRONSULFUR & NEONBORON & 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

THREE TYPES OF MIXTURES SOLUTIONSSUSPENSIONSCOLLOIDS appears to be a single substance but is made of two or more substances that are distributed evenly particles of a material are dispersed in a liquid or gas but are large enough that they settle out particles are dispersed throughout but are not heavy enough to settle out Salt water, alloys, airBlood, Italian dressingMilk, mayonnaise, jello

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

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 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 HEAT

ENDOTHERMIC & EXOTHERMIC An exothermic reaction releases energy –Energy is removed (ex: burning) An endothermic reaction absorbs energy – Energy is added (ex: photosynthesis) ENERGY

Change of State In a change of state, the energy of a substance changes. CHANGE OF STATEDIRECTION ENDOTHERMIC OR EXOTHERMIC? MELTINGSOLID  LIQUIDENDOTHERMIC FREEZINGLIQUID  SOLIDEXOTHERMIC VAPORIZATIONLIQUID  GASENDOTHERMIC CONDENSATIONGAS  LIQUIDEXOTHERMIC SUBLIMATIONSOLID  GASENDOTHERMIC