Science SurveyScience Survey

Chemical and Chemical and Physical Properties Physical Properties

of Matterof Matter

MatterMatter

MatterMatter is anything that has mass is anything that has mass and takes up space.and takes up space.

Chemistry Chemistry is the study of matter is the study of matter and how it changes.and how it changes.

2Classifying Matter2Classifying Matter

Pure substance (substance) – matter Pure substance (substance) – matter that always has exactly the same that always has exactly the same compositioncomposition

Ex. Table Salt, Table SugarEx. Table Salt, Table Sugar

Every sample has the same properties Every sample has the same properties due to a fixed, uniform composition.due to a fixed, uniform composition.

Element – substance that contains Element – substance that contains only one type of atom, cannot be only one type of atom, cannot be broken into simpler substancesbroken into simpler substances

Atom – smallest particle of an elementAtom – smallest particle of an element

Ex. – Carbon, Oxygen, Nitrogen, Gold, Ex. – Carbon, Oxygen, Nitrogen, Gold, Silver, Calcium, etc.Silver, Calcium, etc.

Matter: CompoundsMatter: Compounds A substance made of A substance made of

atoms of more than atoms of more than one element bound one element bound together is a together is a compoundcompound. Ex) . Ex) water, NaClwater, NaCl

Every compound is Every compound is unique, and is different unique, and is different from the elements it from the elements it contains. contains.

Elements and Elements and compounds are pure compounds are pure substancessubstances

Matter: Compounds, Matter: Compounds, cont.cont.

The smallest unit of a compound that The smallest unit of a compound that exhibits all of the properties of that exhibits all of the properties of that substance is a substance is a molecule.molecule.

Chemical formula- the chemical symbols Chemical formula- the chemical symbols and numbers indicating the atoms and numbers indicating the atoms contained in a molecule of a substancecontained in a molecule of a substance

Mixtures – composition is not fixed, Mixtures – composition is not fixed, properties may varyproperties may vary Ex. Salsa, spaghetti sauce, sand, salad Ex. Salsa, spaghetti sauce, sand, salad

dressing, salt waterdressing, salt water

Heterogeneous Mixtures – parts are Heterogeneous Mixtures – parts are noticeably different from one anothernoticeably different from one another

Homogenous Mixtures – substances Homogenous Mixtures – substances are so evenly distributed that it are so evenly distributed that it appears to contain only one substanceappears to contain only one substance

Heterogeneous Heterogeneous HomogeneousHomogeneous

Solutions, Suspensions, Solutions, Suspensions, ColloidsColloids

Solution – formed when substances dissolve Solution – formed when substances dissolve and for a homogeneous mixture; particles are and for a homogeneous mixture; particles are too small to settletoo small to settle

Suspension – heterogeneous mixture that Suspension – heterogeneous mixture that separates into layers over time; larger separates into layers over time; larger particlesparticles

Colloids – contain intermediate sized particles; Colloids – contain intermediate sized particles; do not separate into layers; particles scatter do not separate into layers; particles scatter lightlight

States of MatterStates of Mattersolid - definite shape and volume, particles are close together in fixed positions.

liquid - definite volume, indefinite shape. Particles are close together, but can still slide past each other. Liquids take the shape of their container.

Viscosity is the resistance of a fluid to flow. For example, syrup is more viscous than water.

States of Matter, cont.States of Matter, cont. gas - neither definite shape nor definite

volume; particles are far apart. Gases are free to move in all directions.

plasma- high temperature state of matter where atoms lose their electrons. Plasma is found in fluorescent bulbs, lightning, and stars.

**The forces holding solids together are **The forces holding solids together are stronger than the forces holding liquids stronger than the forces holding liquids together. The forces holding gas particles together. The forces holding gas particles together are the weakest.together are the weakest.

Phase Model for Water

Kinetic Theory and States of Kinetic Theory and States of MatterMatter

Energy of motion is Energy of motion is kinetickinetic energy. The energy. The kinetic theory says that all atoms are in kinetic theory says that all atoms are in motion. motion.

Increasing temperature causes particles to Increasing temperature causes particles to speed up. Decreasing temperature slows speed up. Decreasing temperature slows them down.them down.

At the same temperature, heavier particles At the same temperature, heavier particles move slower than lighter particles.move slower than lighter particles.

Matter can change states if the movement Matter can change states if the movement of the molecules changes.of the molecules changes.

Changes of StateChanges of State Energy is the ability to change or move Energy is the ability to change or move

matter.matter. Energy is needed for matter to change Energy is needed for matter to change

state, such as from a solid to liquid, or state, such as from a solid to liquid, or from liquid to gas.from liquid to gas.

Endothermic Endothermic processes require added processes require added energy, while energy, while exothermicexothermic process release process release energy to the environment.energy to the environment.

EvaporationEvaporation is the change of a substance is the change of a substance from a liquid to a gas. from a liquid to a gas.

CondensationCondensation is the change of a gas to is the change of a gas to liquid form.liquid form.

SublimationSublimation is the change of a solid is the change of a solid directly to a gas.directly to a gas.

Endothermic and Exothermic changes of State

Laws of ConservationLaws of Conservation Changing the state of matter does not Changing the state of matter does not

change its composition or mass.change its composition or mass. Law of Conservation of Mass-Law of Conservation of Mass- Mass cannot Mass cannot

be created or destroyed.be created or destroyed. Law of Conservation of Energy-Law of Conservation of Energy- Energy Energy

cannot be created or destroyed.cannot be created or destroyed. Mass and energy can change forms. For Mass and energy can change forms. For

example, when an ice cube melts, the example, when an ice cube melts, the mass of liquid water is the same as the mass of liquid water is the same as the mass of the ice cube.mass of the ice cube.

Chemical propertiesChemical properties

Chemical property-Chemical property- the way a the way a substance reacts with others to form substance reacts with others to form a new substance with different a new substance with different properties.properties.

ExamplesExamples: Gasoline is flammable.: Gasoline is flammable.

Physical propertiesPhysical properties

Physical property-Physical property- a characteristic a characteristic of a substance that can be observed of a substance that can be observed or measured without changing the or measured without changing the composition of the substance.composition of the substance.

ExamplesExamples: shape, color, odor, : shape, color, odor, texture, boiling point, densitytexture, boiling point, density

Comparison of Chemical and Physical properties

Physical Properties

Viscosity – a liquid’s resistance to flowingThe greater the viscosity, the slower the liquid flows and vice versa

Conductivity – a material’s ability to allow heat to flow

Malleability – ability of a solid to be hammered without shattering

Physical properties: Physical properties: DefinitionsDefinitions

Boiling point-Boiling point- temperature at which temperature at which a liquid becomes a gas below the a liquid becomes a gas below the surface. Water boils at 100surface. Water boils at 10000 C and C and freezes at 0freezes at 00 0 C.C.

Freezing point-Freezing point- the temperature at the temperature at which a liquid becomes a solid.which a liquid becomes a solid.

Melting point-Melting point- the temperature at the temperature at which a solid becomes a liquid.which a solid becomes a liquid.

Chemical ChangesChemical Changes

Chemical changesChemical changes occur when a occur when a substance changes composition by substance changes composition by forming one or more forming one or more newnew substances.substances.

2.3 Chemical Properties2.3 Chemical Properties

Flammability – ability to Flammability – ability to burn in the presence of burn in the presence of oxygenoxygen

Reactivity – how readily a Reactivity – how readily a substance combines chemically substance combines chemically with other substanceswith other substances

Ex. Rust forms when iron reacts with oxygen Ex. Rust forms when iron reacts with oxygen and waterand water

Recognizing Chemical Recognizing Chemical ChangesChanges

Three types of evidence for chemical Three types of evidence for chemical changechange Change in colorChange in color

Examples:Examples:Jewelry tarnishingJewelry tarnishingBananas turning black Bananas turning black

Production of a Gas – bubbling, Production of a Gas – bubbling, fizzingfizzing

Formation of a PrecipitateFormation of a Precipitate Precipitate – solid that forms and Precipitate – solid that forms and

separates from a liquid mixtureseparates from a liquid mixture

Physical ChangesPhysical Changes

Physical change-Physical change- A change in the A change in the physical form or properties of a physical form or properties of a substance that occurs without a substance that occurs without a change in the identity of the change in the identity of the substance.substance.

Physical changes, cont.Physical changes, cont.

Dissolving a substance in solution is Dissolving a substance in solution is a physical change, such as dissolving a physical change, such as dissolving a solid in a liquid or a liquid in a a solid in a liquid or a liquid in a liquid.liquid.

Changes of state, such as melting, Changes of state, such as melting, evaporating, boiling, condensing, and evaporating, boiling, condensing, and freezing are all physical changes.freezing are all physical changes.

Braiding hair is a Braiding hair is a reversible phys. reversible phys. changechange

Cutting hair is a phys. Change that is not reversible