2Chemistry is……the study of the composition, structure, and properties of matter and the changes it undergoesC2H5OH O2 2 CO2 + 3 H2O + EnergyReactants Products
3Matter Mass Anything that has mass and occupies space A measure of the amount of matter
4Atom Element The smallest unit of an element that maintains the properties of that elementElementA pure substance made of only one kind of atom
5Compound A substance that is made from the atoms of two or more elements that are chemically bonded.Sucrose – C12H22O11Sucrose is also known as table sugar, and is used to make Gummy Bears!
6Properties of Matter Extensive properties depend on the amount of matter that is present.Extensive propertiesVolumeMassEnergy Content (think Calories!)do not depend on the amount of matter present.Intensive propertiesMelting pointBoiling pointDensity
7Physical ChangeA change in a substance that does not involve a change in the identity of the substance.Example:Phase Changes
8Phase DifferencesSolid – definite volume and shape; particles packed in fixed positions.Liquid – definite volume but indefinite shape; particles close together but not in fixed positionsGas – neither definite volume nor definite shape; particles are at great distances from one anotherPlasma – high temperature, ionized phase of matter as found on the sun.
18Separation of a Compound The Electrolysis of water Compounds must be separated by chemical means.With the application of electricity, water can be separated into its elementsReactant ProductsWater Hydrogen + OxygenH2O H O2
19PeriodThe Periodic TableGroup or FamilyGroup or familyPeriod
20Properties of MetalsMetals are good conductors of heat and electricityMetals are malleableMetals are ductileMetals have high tensile strengthMetals have luster
21Examples of MetalsPotassium, K reacts with water and must be stored in keroseneCopper, Cu, is a relatively soft metal, and a very good electrical conductor.Zinc, Zn, is more stable than potassiumMercury, Hg, is the only metal that exists as a liquid at room temperature
22Properties of Nonmetals Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.Nonmetals are poor conductors of heat andelectricityNonmetals tend to be brittleMany nonmetals are gases at room temperature
23Examples of NonmetalsMicrospheres of phosphorus, P, a reactive nonmetalSulfur, S, was once known as “brimstone”Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure
24Properties of Metalloids Metalloids straddle the border between metals and nonmetals on the periodic table.They have properties of both metals and nonmetals.Metalloids are more brittle than metals, less brittle than most nonmetallic solidsMetalloids are semiconductors of electricitySome metalloids possess metallic luster
25Silicon, Si – A Metalloid Silicon has metallic lusterSilicon is brittle like a nonmetalSilicon is a semiconductor of electricityOther metalloids include:Boron, BGermanium, GeArsenic, AsAntimony, SbTellurium, Te