Matter and Change Chapter 2

Matter  Chemistry is the study of matter & the changes that it undergoes  Matter is anything that has mass & take up space  Mass is measurement of the amount of matter an object contains

States of matter  A solid is a form of matter that has a definite shape and volume.  The shape of a solid doesn’t depend on the shape of its container.  The particles in a solid are packed tightly together, often in an orderly arrangement.

 Liquids : a form of matter that has varying shape (takes the shape of the container), flows, and yet has a fixed volume.  The particles in a liquid are in close contact with one another, but the arrangement of particles in a liquid is not rigid or orderly.

 A gas is a form of matter that takes both the shape and volume of its container ( no shape or volume of its own).  The particles in a gas are usually much farther apart than the particles in a liquid. The words vapor and gas are sometimes used interchangeably. But there is a difference. The term gas is used for substances, like oxygen, that exist in the gaseous state at room temperature. Vapor describes the gaseous state of a substance that is generally a liquid or solid at room temperature, as in water vapor.

But what happens if you raise the temperature to super-high levels… between 1000°C and 1,000,000,000°C ? Will everything just be a gas?

STATES OF MATTER PLASMA  A plasma is an ionized gas.  A plasma is a very good conductor of electricity and is affected by magnetic fields.  Plasmas, like gases have an indefinite shape and an indefinite volume. Plasma is the common state of matter

Some places where plasmas are found… 1. Flames

2. Lightning

3. Aurora (Northern Lights)

The Sun is an example of a star in its plasma state

PHASE CHANGES Description of Phase Change Term for Phase Change Heat Movement During Phase Change Solid to liquid Melting Heat goes into the solid as it melts. Liquid to solid Freezing Heat leaves the liquid as it freezes.

PHASE CHANGES Description of Phase Change Term for Phase Change Heat Movement During Phase Change Liquid to gas Vaporization, which includes boiling and evaporation Heat goes into the liquid as it vaporizes. Gas to liquidCondensation Heat leaves the gas as it condenses. Solid to gasSublimation Heat goes into the solid as it sublimates.

STATES OF MATTER SOLID LIQUID GAS PLASMA Tightly packed, in a regular pattern Vibrate, but do not move from place to place Close together with no regular arrangement. Vibrate, move about, and slide past each other Well separated with no regular arrangement. Vibrate and move freely at high speeds Has no definite volume or shape and is composed of electrical charged particles

Properties of Matter  Physical Properties – a characteristic that can be observed or measured w/out changing the identity of a substance  ex. color, odor, taste, hardness, density, melting/boiling points, state of matter

Physical Changes – a change that occurs in the physical appearance of a substance, but does not change its identity  Ex. melting, boiling, freezing, evaporating, dissolving, condensing, breaking, splitting, grinding, cutting, crushing

SubstanceStateColor Melting Point (C°) Boiling Point (C°) Density (g/cm 3 ) OxygenO2O2 GasColorless MercuryHgLiquidSilvery-white BromineBr 2 LiquidRed-brown WaterH2OH2OLiquidColorless Sodium Chloride NaClSolidWhite Example: Physical Properties

Chemical Properties – relates to a substances ability to undergo changes that transform it into a different substance  easiest to see when a chemical is reacting Chemical changes – the composition of the matter always changes.  ex. burning, rotting, rusting, reacting, cooking, digestion, respiration

Chemical Reactions  The process by which the atoms of one or more substances are rearranged to form different substances  Also known as a chemical change Reactants substances to the left of the arrow ‘ingredients’ CO 2 and H 2 O Products substances to the right of the arrow ‘what is made’ or produced C 6 H 12 O 6 and O 2

Recognizing Chemical Changes 1. Transfer of Energy2. Change in color 3. Formation of Precipitate4. Gas production

 Substance : matter that has uniform and definite composition. Any given substance has identical intensive properties ….. Why?  because every sample has the same composition

Pure Substances Every sample has the same characteristics properties and composition Element  Simplest form of matter that has its own unique set of properties  Can not be separated into simpler substances by physical or chemical means  Each element is made up of a single type of atom ex. hydrogen, nitrogen, lead Compound  A substance that contains 2 or more elements chemically combined in a fixed proportion  Properties are different than the individual elements ex. Glucose (sugar)

Symbols & Formulas  Chemical Symbol each element is represented by a one- or two-letter symbol Trends: 1 st letter = always capitalized 2 nd letter = always lowercase Subscripts = indicate the relative proportions of the elements in a compound H K Au H2OH2O C 6 H 12 O 6 Hydrogen Potassium GoldWaterGlucose

Periodic Table  All the known elements are organized in a special table called the periodic table. A periodic table is an arrangement of elements in which the elements are separated into groups based on a set of repeating properties.

Each element is identified by its symbol placed in a square.

Mixtures  A combination of 2 or more types of matter  Each component keeps its own identity & properties  Components are only physically mixed & can be separated using physical means

Types of Mixtures Heterogenous Mixture  a mixture in which the substances are not evenly distributed  Ex: Salads, oil & vinegar, iced tea with ice. Homogenous Mixture  a mixture or ‘solution’ in which the substances are evenly distributed  Ex: salt water, kool aid solution, stainless steel.

Heterogenous Mixture  Colloid  Suspended particles are not dense enough to settle out, yet are unevenly distributed  Ex: blood, milk, glue, fog, smoke, cosmetics, detergents, paints  Suspension  Suspended particles in this mixture will settle out  Phase: distinct layer with uniform composition  Ex: oil and water = 2 phases  Salad dressing: water and vinegar = phase 1, oil = phase 2, seasoning = phase 3

Gold as an alloy  Alloy – a homogeneous mixture of metal  - Properties of alloys vary based on the composition of the component elements

Separating Mixtures  Differences in physical properties can be used to separate mixtures.  Different techniques used for separation: Filtration: a technique that uses a porous barrier to separate a solid from a liquid

Separating Mixtures Distillation: is a technique that is used to physically separate most homogeneous mixtures based on differences in the boiling points of the substances involved.

Distillation of Crude Oil

Separating Mixtures Chromatography: is a technique that is used to physically separate the components of a mixture based on the tendency of each component to travel or be drawn across the surface of another material.

Substances vs. Mixtures

Propeties of Matter  Extensive property that depends on the amount of matter in a sample.  Mass and volume are extensive property  Intensive property that depends on the type of matter in a sample.  Hardness, density, boiling point, electrical conductivity

Law of Conservation of Mass  In any physical or chemical change, mass is conserved  i.e. Mass is neither created or destroyed

The law of conservation of mass is more easily observed when a change occurs in a closed container. When the liquids in the figure at left are mixed, they react. None of the products are gases.

Concept Mapping COMPLETE THE GRAPHIC ORGANIZER 1.Define each state of matter. 2.How are the particles packed? 3.Draw a model showing how the particles are packed. 4.Give 3 examples of each. 5.Does it have definite shape, definite volume, or both? SOLID LIQUID GAS States Of Matter