Matter and Change

Properties of Matter What is mass? 1.) The force of gravity on an object. 2.) The amount of matter an object contains. 3.) The measure of space occupied by an object.

Mass and Volume Mass – the amount of matter an object contains (grams) Volume – measure of space occupied by an object (cm3, mL, L)

Extensive vs. Intensive Properties Extensive Properties – depends on amount of matter Example: mass and volume Intensive Properties – depends on type of matter, not amount Example: color and density

Identifying Substances Substance – matter with uniform and definite composition - sample of given substance has same intensive properties

Physical Properties Physical Properties – quality or condition of substance that can be observed or measured without changing composition Physical states of matter - Solid - Liquid - Gas

States of Matter Solid – matter with definite shape and volume - particles packed tightly together - not easily compressed

States of Matter Liquid- Indefinite shape, flows, definite volume - flowing/loosely packed molecules - not easily compressed

States of Matter Gas – indefinite shape and volume - molecules spaced out - easily compressed Vapor- gaseous state of substance that was generally a liquid or solid at room temp

Physical Changes Physical Change – when properties change but composition does not - Example: ice water

Mixtures Mixtures – physical blend of 2 or more components Example: salad (tomatoes, lettuce, onions, etc.)

Heterogeneous Mixtures Heterogeneous Mixtures – composition not uniform - Example: Chicken noodle soup (more chicken in one spoonful than another)

Homogeneous Mixtures Homogeneous Mixtures – composition uniform throughout Example: salt water Solution- homogeneous mixture (mostly liquids/some gases)

Phase Phase – any part of sample with uniform composition and properties -Homogeneous = 1 phase -Heterogeneous = 2 phases or more 1 phase 1 phase

Separating Mixtures Differences in physical properties can be used to separate mixtures. Filtration – separate solid from liquid in heterogeneous mixtures

Separating Mixtures Distillation – process used to separate dissolved solids from liquid - liquid boiled to produce vapor and condensed into liquids

Elements and Compounds Element – simplest form of matter - has unique set of properties - can not be broken into simpler substances - Example: Oxygen and Hydrogen

Compound Compound – substance contains 2 or more elements - chemically combined in fixed proportion - can be broken down into simpler substances - Example: Carbon Dioxide (CO2)

Breaking Down Compounds Chemical Change- produces matter with different composition Example: Water Hydrogen + Oxygen electricity

Properties of Compounds Properties of compounds different from component elements. Example: Hydrogen = explosive/flammable Oxygen = flammable Water (H2O) = puts fires out

Substances vs. Mixtures Composition fixed = substance Example: Carbon Monoxide (1Carbon:1Oxygen) Composition varies = mixture Example: chicken soup

Symbols and Formulas Chemical Symbol – each element represented by 1 or 2 letter symbol - first letter capitalized - second is lowercase

Symbols and Formulas Chemical formulas represent compounds Example: Sucrose (table sugar) = C12H22O11

Chemical Changes Chemical Property – ability of substance to undergo chemical change - during chemical change composition of matter always changes - Example: burn, rot, rust, decompose, ferment, explode, corrode

Chemical Changes Chemical Reaction – one or more substances change into one or more new substances - Reactant – substance at beginning of reaction - Product – substance produced in reaction Example: HCl + NaOH NaCl + H2O

Recognizing Chemical Change Clues to chemical change include: - transfer of energy - change in color - production of gas - formation of precipitate - precipitate – solid that forms and settles out of liquid mixture

Conservation of Mass Law of Conservation of Mass- in any physical change or chemical reaction mass is conserved - mass of products = mass of reactants