3 The study of properties of matter and how matter changes Chapter 2 NotesChemistryThe study of properties of matter and how matter changesPhysical propertiesMatter has two kinds of propertiesChemical propertiesMatterAnything that has mass and takes up spaceSubstanceThe same composition and propertiesAlways hasA single kind of matter that is pure
4 Can be used to classify matter Chapter 2 NotesProperties of MatterPhysical propertyChemical propertyCharacteristic of a pure substance that can be seen without changing it into another substanceCharacteristic of a pure substance that describes its ability to change into different substancesExampleExampleCan be used to classify matterLiquid water freezing into iceIron combines with oxygen to form rust
5 Elements are the simplest substance! Chapter 2 NotesElementElements are the simplest substance!Pure substance that cannot be broken down into any other substance by chemical or physical meansMoleculesGroup of 2 or more atoms held together by a chemical bondWhen atoms combineA chemical bond forms- a force of attraction between the two atomsExampleThe basic particle from which all elements are madeTwo Hydrogen atoms and one Oxygen atom forms waterAtoms
6 C O C O 2 Chapter 2 Notes Compounds Chemical Formula Pure substance made of two or more different elements chemically combined in a set ratioShows the elements in a compound and the ratio of atomsElements that are chemically combined have different properties from the uncombined elementsChemical FormulaCOCO2A different ratio equals a different compoundThe ratio of Carbon to Oxygen is 1:2
7 Compounds- The combined elements change their properties. Chapter 2 NotesContrastMixtureCompounds- The combined elements change their properties.Mixtures- The combined elements keep their properties.A mix of two or more substances that retain their own propertiesHeterogeneousHomogeneousMixture where you can see the different partsMixture where you cannot see the different partsA homogeneous mixture is called a solutionExamplesSalad in a bowlDissolved sugar in water
9 The measure of the force of gravity on you WeightMassThe measure of the force of gravity on youThe measure of the amount of matter in an objectRelates toUnitsGrams (g)Does not change with locationFormulaVolume = Length x Width x HeightUnitsDensityg / cm3VolumeThe mass of a material in a given volumeThe amount of space that matter occupiesFormulaUnitsDensity = MassVolumeLiter (L), milliliter (mL) and cubic centimeter (cm3)
11 Combination of fuel with oxygen Physical ChangeChemical ChangeWhen a substance changes, but is still the same substance after the changeWhen a substance changes into a new substance with properties different from the originalCombustionCombination of fuel with oxygenChanges of stateElectrolysisUsing electricity to break down compoundsChanges of shape or formOxidationTarnishingCombination of substance with oxygenCombining metals with substances, producing dark coat on metal
12 A change in matter that produces one or more new substances Chemical ReactionsChanges in ColorA change in matter that produces one or more new substancesA color change may signal that a chemical change has occurredChemical changes occur when bonds break and new bonds formPrecipitate may formA solid that forms from solution during a chemical reaction is a precipitateEvidence for chemical Reactions, or changesA gas may formIf a chemical change occurs from liquids or solids, a gas may form
13 The next video shows a color change, and a precipitate!
15 Chemical or physical changes in matter includes a change in energy The ability to do work or cause changeAlways flows from hot to coldTemperatureThermal EnergyThe average energy from the random motion of matter particlesThe total energy of all the particles in an objectEndothermic ChangeExothermic ChangeChange in which energy is taken inChange in which energy is released
16 + Law of Conservation of Mass All the atoms present at the start of a reaction are present at the endMatter cannot be created or destroyedIn a chemical reaction, the total mass of the reactants must equal the total mass of the productsMatter can only be changed!Iron (6 atoms)Sulfur (6 atoms)Iron Sulfide (12 atoms)+
18 The energy of matter in motion Kinetic EnergyPotential EnergyThe energy of matter in motionThe energy an object has because of its positionForms of EnergyElectric EnergyChemical EnergyElectromagnetic EnergyEnergy of electrically charged particles moving from one place to anotherEnergy stored in chemical bondsEnergy form that travels through space as wavesChemical energy may be changed to other forms of energy. Other forms of energy may also be changed to chemical energy!