introductory chemistry a foundation fourth edition by steven ：介绍化学基础第四版史提芬

1,Matter and EnergyChapter 3,2,Properties,Characteristics of the substance under observationProperties can be either directly observable orthe manner something interacts with other substances in the universe,3,Universe Classified,Matter is the part of the universe that has mass and volumeEnergy is the part of the universe that has the ability to do workChemistry is the study of matterThe properties of different types of matterThe way matter behaves when influenced by other matter and/or energy,4,Properties of Matter,Physical Properties are the characteristics of matter that can be changed without changing its compositionCharacteristics that are directly observableChemical Properties are the characteristics that determine how the composition of matter changes as a result of contact with other matter or the influence of energyCharacteristics that describe the behavior of matter,5,Classify Each of the following as Physical or Chemical Properties,The boiling point of ethyl alcohol is 78C.Physical property describes inherent characteristic of alcohol boiling pointDiamond is very hard.Physical property describes inherent characteristic of diamond hardnessSugar ferments to form ethyl alcohol.Chemical property describes behavior of sugar forming a new substance (ethyl alcohol),6,solid, liquid, gas,States of Matter,7,Figure 3.2: The three states of water,8,Changes in Matter,Physical Changes are changes to matter that do not result in a change of the fundamental components that make that substanceState Changes boiling, melting, condensingChemical Changes involve a change in the fundamental components of the substanceProduce a new substanceChemical reactionReactants Products,9,Figure 3.3: Electrolysis,10,Classify Each of the following as Physical or Chemical Changes,Iron is melted.Physical change describes a state change, but the material is still ironIron combines with oxygen to form rust.Chemical change describes how iron and oxygen react to make a new substance, rustSugar ferments to form ethyl alcohol.Chemical change describes how sugar forms a new substance (ethyl alcohol),11,Elements and Compounds,Substances which can not be broken down into simpler substances by chemical reactions are called elementsMost substances are chemical combinations of elements. These are called compounds.Compounds are made of elementsCompounds can be broken down into elementsProperties of the compound not related to the properties of the elements that compose itSame chemical composition at all times,12,Classification of Matter,Homogeneous = uniform throughout, appears to be one thingpure substancessolutions (homogeneous mixtures)Heterogeneous = non-uniform, contains regions with different properties than other regions,Heterogeneous,13,Pure Substances vs. Mixtures,Pure SubstancesAll samples have the same physical and chemical propertiesConstant Composition all samples have the same compositionHomogeneousSeparate into components based on chemical propertiesMixturesDifferent samples may show different propertiesVariable compositionHomogeneous or HeterogeneousSeparate into components based on physical propertiesAll mixtures are made of pure substances,14,Figure 3.4: Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right),15,Figure 3.5: Sand and water do not mix to form a uniform mixture,16,Identity Each of the following as a Pure Substance, Homogeneous Mixture or Heterogeneous Mixture,Gasoline a homogenous mixtureA stream with gravel on the bottoma heterogeneous mixtureCopper metalA pure substance (all elements are pure substances),17,Separation of Mixtures,Separate mixtures based on different physical properties of the componentsPhysical change,18,Figure 3.6: Distillation of a solution consisting of salt dissolved in water,19,Figure 3.7: No chemical change occurs when salt water is distilled,20,Figure 3.8: Filtration separates a liquid from a solid,21,Figure 3.9: Separation of a sand-saltwater mixture,22,Figure 3.10: The organization of matter,23,Energy and Energy Changes,Capacity to do workchemical, mechanical, thermal, electrical, radiant, sound, nuclearEnergy may affect mattere.g. raise its temperature, eventually causing a state changeAll physical changes and chemical changes involve energy changes,24,Units of Energy,One calorie is the amount of energy needed to raise the temperature of one gram of water by 1Ckcal = energy needed to raise the temperature of 1000 g of water 1Cjoule 4.184 J = 1 calIn nutrition, calories are capitalized1 Cal = 1 kcal,25,Example - Converting Calories to Joules,Convert 60.1 cal to joules,26,Energy and the Temperature of Matter,The amount the temperature of an object increases depends on the amount of heat added (Q).If you double the added heat energy the temperature will increase twice as much.The amount the temperature of an object increases depends on its massIf you double the mass it will take twice as much heat energy to raise the temperature the same amount.,27,Specific Heat Capacity,Specific Heat (s) is the amount of energy required to raise the temperature of one gram of a substance by one Celsius degree,Amount of Heat = Specific Heat x Mass x Temperature ChangeQ = s x m x T,28,Example Calculate the amount of heat energy (in joules) needed to raise the temperature of 7.40 g of water from 29.0C to 46.0C,Mass = 7.40 g,Temperature Change = 46.0C 29.0C