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Chemistry. Matter: Phases and Changes. Kinetic Molecular Theory Explains the forces between molecules and the energy that they possess. Matter is composed of small particles ( molecules, ions, atoms ).
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Chemistry Matter: Phases and Changes
Kinetic Molecular TheoryExplains the forcesbetween molecules and theenergythat they possess • Matteris composed of small particles (molecules, ions, atoms). • The energy and organization of these particles determines the physical state and properties of matter. • All particles are in constant, random motion and possess kinetic energy. • The amount of kinetic energy is directly related to temperature. Kinetic energy is transferred from one particle to another through collisions.
There are three different, common physical states of matter.
Solids • Strong intermolecular attractions hold individual particles close together • Particles vibrate • Defined volumes and shapes and do not flow • High densities
Liquids • Particles are randomly packed and close to each other • Intermolecular attractions between particles is not as strong as in solids • Particles slide over each other but do not completely separate • Definite volume but an indefinite shape (take the shape of their containers) • Flow.
Gases • Intermolecular attractions between particles is very small • Particles move far apart from each other • Particles are in constant, random motion, independent of each other • No specific shape or volume ( take the shape of their containers ) • Low densities • Flow
Review Questions • A student ran tests on a mystery substance and found that is has a definite volume, high density, and flows easily. Which state of matter is it and why? • It is a solid because it has a definite volume and high density. • It is a liquid because it has a definite volume and high density. • It is a gas because it has a definite volume and flows easily. • It is a liquid because it has a definite volume and flows easily. • Which of the following correctly describes the motion of particles in a solid? • They do not move at all. • They move rapidly around in random patterns. • They vibrate in a set pattern. • They flow easily, but slowly around each other.
Physical Changes Changes in form Crushing Tearing Changes in State Melting Freezing Etc Chemical Changes Changes in Substance Cannot be Unchanged Burning Rust Cooking Digesting Tarnishing Changes in MatterBottom of pg 7
Which are three examples physical changes? D. gasoline burning, an egg rotting, fireworks exploding. • water freezing, gasoline, evaporating, a nail rusting. B. water boiling, a balloon bursting, a candle melting. • C. wood burning, a marshmallow melting, a paper tearing.
Which are three examples physical changes? D. gasoline burning, an egg rotting, fireworks exploding Incorrect. Chemical change. • water freezing, gasoline, evaporating, a nail rusting Incorrect. Chemical change. B. water boiling, a balloon bursting, a candle melting Correct. Physical change. C. wood burning, a marshmallow melting, a paper tearing Incorrect. Chemical change.