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Chapter 1 The Foundations of Chemistry,1,Chapter Outline,Matter and Energy 物質與能量 Chemistry A Molecular View of Matter States of Matter Chemical and Physical Properties 化學與物理性質 Chemical and Physical Changes 化學與物理變化 Mixtures, Substances, Compounds, and Elements Measurements in Chemistry Units of Measurement Use of Numbers The Unit Factor Method (Dimensional Analysis) Percentage 百分比 Density and Specific Gravity 密度與比重 Heat and Temperature Heat Transfer and the Measurement of Heat,2,Chemistry is everywhere Tent plastic Steel cooking grate alloy of iron and carbon Trees Photochemical reaction CO2 + H2O carbohydrate Our bodies inorganic and bioorganic compounds .,3,Chemistry,the science that describes matter properties, the changes it undergoes, the energy changes that accompany those processes 研究物質的特性,組成,結構和變化的科學 Organic Chemistry 有機化學 Inorganic Chemistry 無機化學 Analytical Chemistry 分析化學 Physical Chemistry 物理化學 Biochemistry 生物化學,4,1-1 Matter and Energy,Matter Mass Occupies space Energy: The capacity to do work or transfer heat Kinetic energy & Potential energy 動能 位能 Exothermic & Endothermic 放熱 吸熱,5,Fig. 1-1, p. 4,The Law of Conservation of Matter 物質不滅定律,There is no observable change in the quantity of matter during a chemical reaction or during a physical change.,無論物質經過任何化學變化或物理變化,其反應物的總質量和產物的總質量相同,鎂燃燒生成氧化鎂,6,The Law of Conservation of Matter 物質不滅定律 The law of Conservation of Energy 能量不滅定律 Energy cannot be created or destroyed in a chemical reaction or in a physical change. It can only be converted from one form to another The Law of Conservation of Matter and Energy 質能不滅定律 The combined amount of matter and energy in the universe is fixed Einsteins Relativity E=mc2,7,Daltons Atomic Theory 道耳吞原子學說 (in 1808),Fig1-2 Relative size for atoms of the noble gases,Fig. 1-2, p. 6,1-2 Chemistry A molecular View of Matter,所有的物質都是由極小的微粒所組成, 稱之為原子 (atom) 不同元素 (element)的原子不同, 但同一元素所含的原子均相同 原子是組成物質的最小粒子,不能再分割 化學反應是物質中原子的重新排列或組合 不同元素的原子形成化合物 (compound) 時,原子間的比例為一固定的簡單整數比,8,Table 1-1, p. 6,電子,質子,中子,物質的基本粒子,The basic building blocks of atoms,9,p. 7,Atomic number 原子序 the number of protons in the nucleus,Silver,10,Fig. 1-3, p. 7,A molecule 分子 is the smallest particle of an element or compound that can have a stable independent existence,Fig 1-3 Models of diatomic molecules of some elements, approximately to scale. There are called space-filling models (比例模型) because they show the atoms with their approximate relative size,Others: N2, Cl2, Br2, I2,11,Fig. 1-4, p. 7,Fig 1-4 (a) A model of the P4 molecule of white phosphorus. (b) A model of the S8 ring found in rhombic sulfur (c) Top view of the S8 ring in rhombic sulfur,polyatomic molecules,12,Fig. 1-5, p. 8,Fig 1-5 Formulas and ball-and-stick models for molecules of some compounds. Ball-and-stick (球棍模型) models represent the atoms as a smaller spheres than in space-filling models, in order to show the chemical bonds between the atoms as “stick”,甲烷,乙醇,Compound 化合物,13,Fig. 1-6a, p. 8,National Institute of Science and Technology logo Cobalt atoms on a copper surface,Using the Scanning tunneling Microscope,34 iron atoms arranged on a copper surface,14,Atom 原子 the smallest particle of an element that maintains its chemical identity through all chemical and physical change,Molecule 分子 the smallest particles of an element or compound that can have a stable independent existence,Element 元素 a substance that cannot be decomposed into simpler substance by chemical means,Compound 化合物 composed two or more different elements in fixed proportions can be decomposed into their constituent elements,15,p. 8,i. Krypton 氪,Example 1-1 Models,ii. ethane 乙烷,iii. Nitrogen 氮,iv. Aspirin阿斯匹靈,v. Sulfur dioxide 二氧化硫,vi. Copper 銅,atom,molecule,element,compound,16,1-3 Sates of Matter,Iodine 碘,Bromine 溴,Chlorine 氯,Fig 1-7 p. 9,(s),(l),(g),17,p. 9,Solid (s),Gas (g),Liquid (l),Example 1-2 Models,18,1-4 Chemical and Physical Properties,Chemical properties Chemical change changes in composition 鎂燃燒生成氧化鎂 Physical properties Absence of any change of composition color, density, hardness, melting point, boiling point, and electrical and thermal conductivities State change (ice-water-steam),Extensive Properties 外延性質 Depends on the amount of material in a sample 與尺度有關之性質,如重量、體積、熱. Intensive Properties 內涵性質 Independent of the amount of material in a sample 與尺寸無關之性質,如密度、顏色、黏度、壓力、 溫度、濃度 ,No two different substances have identical sets of chemical and physical properties,19,Fig. 1-8, p. 11,Endothermic (absorb heat),Exothermic (release heat),蒸發/凝結,冷凍/溶化,昇華/沉澱,Physical Changes Occur among the three states of matter,20,Fig. 1-9a, p. 12,Physical properties: melts at 0oC boils at 100oC dissolves a wide range of substances,Chemical properties: (d) water reacts violently with sodium to form hydrogen gas and sodium hydroxide,Water,21,Table 1-2, p. 12,醋酸,苯,溴,鐵,甲烷,氧氣,氯化鈉,22,Fig. 1-10, p. 13,1-5 Chemical and physical changes,Chemical change One or more substances are used up One or more new substances are formed Energy is absorbed or released Physical change No change in chemical composition Change in energy,solid,liquid,liquid,gas,23,p. 13,1-6 Mixtures, Substances, Compounds, and Elements,Mixture have variable composition May be separated by physical methods components retain its properties Mixture of different components may have widely different properties Heterogeneous mixture 非均勻混合物 Do not have same composition throughout Components are distinguishable Salt and charcoal, foggy air, vegetable soup Homogeneous mixture (solution) Have same composition throughout Components are indistinguishable Salt water, alloys, air,Galena(方鉛礦) and quartz (石英),24,Fig. 1-11a, p. 15,A mixture of iron and sulfur is a heterogeneous mixture,It ca be separated by physical means, such as removing the iron with magnet,25,Fig. 1-12, p. 15,26,Electrolysis apparatus for small-scale chemical decomposition of water by electric energy,(88.9%),(11.1%),Fig. 1-13, p. 16,Chemical decomposition of liquid water,Water as a compound!,27,Fig. 1-14, p. 17,Compound,Compound Calcium Oxide,elements,Fig 1-14 Diagram of the decomposition of calcium carbonate,elements,A compound is a pure substance consisting of two or more different elements in a fixed ratio Law of definite Proportions 定比定律 (Law of Constant Composition),Heat,Compound Carbon dioxide,28,Fig. 1-15, p. 17,The physical and chemical properties of a compound are different from the properties of its constituent elements,Sodium Chloride (NaCl) White solid This compound is formed by the combination of sodium and chloride Sodium A soft, silvery white metal Chloride A pale green, corrosive, poisonous gas Na + Cl NaCl Light and Heat Produce,29,Table 1-3, p. 18,硼,鋇,鉍,溴,鎘,鈣,碳,氯,鈷,鉻,銅,金,鋁,銀,氦,汞,碘,鉀,鎂,鋰,氪,錳,氮,鈉,氖,氫,鐵,氟,鉛,鉑,硫,鍗,鍶,錫,矽,鈦,鈾,鎢,鋅,磷,氧,鎳,30,Table 1-4, p. 18,10/88 naturally occurring elements make up more than 99% by mass,Living matter,No biological role,31,Table 1-5, p. 19,1-7 Measurements in Chemistry,發光強度,電流,長度,質量,燭光,絕對溫標,莫耳數 克分子量,時間,溫度,物質數量,The international System of Units (SI) metric system 公制,32,Table 1-6, p. 19,SI: the international system of units,33,1-8 Units of Measurement,Mass (質量): doesnt vary as its position change Weight (重量): is a measure of the gravitational attraction of the earth for the body, and this varies with distance from the center of the earth,Triple-beam balance 0.01g 三樑天平,Electronic top-load balance 0.001g 電子秤,Analytical balance 0.0001g 電子分析天平,Fig. 1-16a, p. 20,34,Fig. 1-17 1-18, p. 21,Length,inch,centimeter,Volume,Beaker 150ml 燒杯,buret 25ml玻璃量管,volumetric flask 1000ml 定量瓶,Graduated cylinder 100ml 量筒,volumetric pipet 10ml 定量吸管,Flask 錐形瓶,Liters=1000cm3,milliliter=1cm3= 1cc,35,Table 1-8, p. 21,Appendix C Common Units, Equivalences, and Conversion Factors Page A-8 to A-10 in textbook,36,Fig. 1-19, p. 23,1-9 Use of Numbers,Scientific Notation 科學記數法,4,300,000=4.3x106 0.000348=3.48x10-4,Significant Figures 有效位數 are digits believed to be correct by the person who makes a measurement,Numbers obtained by counting exact numbers,Numbers obtained measurements are not exact estimate numbers,37,The volume is read at the bottom of the liquid curve (meniscus). Meniscus of the liquid occurs at about 20.15 mL. Certain digits: 20.15 Uncertain digit: 20.15,Measurement of Volume Using a Buret,A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty. Record the certain digits and the first uncertain digit (the estimated number).,38,Fig. 1-20, p. 24,Significant Figures 有效位數,Precision 精確 Degree of agreement among several measurements of the same quantity.,Accuracy 準確 Agreement of a particular value with the true value.,39,Neither accurate nor precise,Precise but not accurate,Both precise and accurate,Precision and Accuracy,40,38.57 4 significant figure 288g 3 significant figure,1. Nonzero digits are always significant .,Some simple rules govern the use of significant figures,41,2. Zeros are sometimes significant , and sometimes they are not a. Zeroes at the beginning of a number are never significant b. Zeroes between nonzero digits are always significant c. Zeroes at the end of a number that contains a decimal point are always significant d. Zeroes are at the end of a number that does not contain a decimal point may or may not be significant,0.052 2 significant figure 5.2x10-2 0.00364 3 significant figure 3.64x10-3 b. 2007 4 significant figure 6.08 3 significant figure,c. 38.0 3 significant figure 440.0 4 significant figure d. 24,300km 3,4,5 significant figure 2.43x104 2.430x104 2.4300x104,42,3. Exact numbers can be considered as having an unlimited number of significant figures. This applies to defined quantities.,1 yard = 3 feet 1,3 are exact Do no apply the rules of significant figures 1 inch= 2.54cm,43,Example Significant Figures,Give the number of significant figures for each of the following results. a. A students extraction procedure on tea yields 0.0105 g of caffeine b. A chemist records a mass of 0.050080 g in an analysis c. In an experiment a span of time is determined to be 8.050x10-3 sec,a. 0.0105g 1.05x10-2g 3 significant figures b. 0.050080g 5.0080x10-2 g 5 significant figures c. 8.050x10-3 sec 4 significant figures,44,4. In addition and subtraction, the last digit retained in the sum or difference is determined by the position of the first doubtful digit,(a) Add 37.24ml and 10.3ml 37.24ml +10.3 ml 47.54 ml is reported as 47.5ml (b) Subtract 21.2342 from27.81 27.87 g - 21.2342g 6.6358 g is reported as 6.64g,45,5. In multiplication and division, an answer contains no more significant figures than the least number of significant figures used in the operation.,4.56 x 1.4 = 6.4 two significant figures What is the area of a rectangle 1.23 cm wide and 12.34cm long? A= l x w =(12.34cm) x (1.23cm) =15.2cm2 (calculator result =15.1782),Exercise 32,46,Example: Significant Figures in Mathematical Operations,Carry out the following mathematical operations, and give each result with the correct number of significant figures. a. 1.05x10-3 6.135 b. 21-13.8 c. (2.560)x(8.8) 275.15,a. 1.05x10-3 6.135 1.71x10-4 3 significant figures b. 21-13.8 7 The number with the least number decimal places (21) has none c. (2.560)(8.8) 275.15 0.0835908 The least precise measurement has 2 significant figures 8.4x10-2,47,1-10 The Unit Factor Method (Dimensional Analysis 因次分析),Example 1-5 Unit Factor Express 1.47 mi. in inches. Miles feet inches 1 mile = 5,280 ft 1 ft = 12 inch,Unit Factor: a factor in which the numerator and denominator are expressed in different units but represent the same or equivalent amounts. 1 ft = 12 in 1=12 in/ft 1=1 ft/12in The reciprocal of any unit factor is also a unit factor,?in. =1.47 mi x,5280ft,mi,x,12in.,ft,=9.31x104 in.,(93139.2),Unit Conversion,Volume Calculation,Mass Conversion,Volume Conversion,Energy Conversion,English-Metric Conversion,Factor-label Method,Exercise 36,Unit Conversion,48,Example 1-6 Unit Conversion The ngestrom () is a unit of length 1x10-10m, that provides a convenient scale on which to express the radii of atoms. Radii of atoms are often expressed in nanometers. The radius of a phosphorus atom is 1.10 (). what is the distance expressed in centimeters and nanometers?,Unit Conversion,= 1.1 ,=1.10x10-8cm,? cm,x,1cm,1x10-2m,1x10-10m,1 ,x,= 1.1 ,=1.10x10-1nm,? nm,x,1nm,1x10-9m,1x10-10m,1 ,x,49,Example : Express 9. 32 yards in millimeters.,Example : Express 627 milliliters in gallons.,= 9.32yd,=8.52x103mm,? mm,x,= ? mm,9.32 yd,=0.166155 gal 0.166 gal,? mm,= 627 ml,? gal,50,Example : Express 2.61 x 104 cm2 in ft2.,Example : Express 2.61 ft3 in cm3,=28.09380619 ft2 28.1 ft2,? ft2,= 2.61x104cm2,x,x,2,2,=73906.9696 cm3 7.39x104 cm3,? cm3,3,x,3,51,p. 31,1-11 Percentage,U.S. pennies made since 1982 consist of 97.6% zinc and 2.4% copper. The mass of a particular penny is measures to be 1.494 grams. How many grams of zinc does in this penny contain?,1.494g sample x,100g sample,97.6g zinc,=1.46g zinc,Exercise 63, 64,52,p. 31, Tabl1 1-9, p.32,1-12 Density and Specific Gravity 密度與比重,Density=,Mass,Volume,D =,m,V,g/cm3 or g/ml for solids and liquids, g/L for gases,gasoline,water,cork,oak,mercury,brass,53,Example 1-13 A 47.3-ml sample of ethyl alcohol has a mass of 37.32g. What is the density?,p. 32,D =,V,37.32 g,47.3 ml,=,= 0.789g/ml,Exercise 40,Example 1-14 If 116g of ethanol is need for a chemical reaction, what volume of liquid would you use?,V =,m,m,D,116 g,0.789g/ml,=,= 147ml,Exercise 42,Example 1-15 Express the density of mercury in lb/ft3?,Mercury density:13.59g/cm3,= 13.59,=848.4lb/ft3,x,1lb,453.6g,x,3,3,D =,V,m,m =,D x V,V =,D,m,54,p. 33,Specific gravity 比重 The ratio of its density to the density of water, both at the same temperature,DiceDwater,Dsolid ethanol Dliquid ethanol,Example 1-16 The density of table salt is 2.16 g/ml at 20oC. What is its specific gravity?,Sp. Gr =,Dsubstance,Dwater,2.16g/ml,1.00g/ml,=,= 2.16,55,Example 1-17 Specific Gravity, Volume, Percentage by Mass Battery acid is 40.0% sulfuric acid, H2SO4, and 60% water by mass. Its specific gravity is 1.31. Calculate the mass of pure H2SO4 in 100ml of battery acid.,40g H2SO4,100g sol,= 100.0ml sol,=52.4g H2SO4,?,x,40.0g H2SO4,100g sol,1.31g sol,1ml sol,x,H2SO4,Exercise 48,40% H2SO4 =,In this case, the specific gravity equal to the density =1.31g/ml,56,Fig 1-22, p. 33,1-13 Heat and Temperature,Heat is a form of energy that always flows spontaneously from a hotter body to a colder body it never flows the reverse direction. Hotter Body Colder Body,Temperature Measure: Mercury thermometer Centigrade temperature scale 0oC 100oC Fahrenheit temperature scale 32oF 212oF Kelvin (absolute) temperature scale ?K=oC+273.15o or ? oC=K-273.15o,Fahrenheit and Centigrade Relationships ?oF=1.8x?oC+32oF,57,Example 1-18 Temperature Conversion When the temperature reaches “100oF” in the shade”, its hot. What is this temperature on the Celsius scale?,?oC=,1.8,oF-32,1.8,100-32,=,= 38oC,Example 1-19 Temperature Conversion When the absolute temperature is 400K, what is this Fahrenheit temperature?,? oC=K-273.15o =400-273 =127oC,?oF=1.8x?oC+32oF =1.8x127+32oF =261oF,Exercise 50,58,1-14 Heat Transfer and the Measurement of Heat,Joule (J): the SI unit of energy and work job 1 J = 1kg m2/s2 Kinetic energy (動能) =1/2 mv2 Calorie: 4.184J,Specific heat (比熱): the amount of heat required to raised the temperature of one gram of the substance one degree Celsius with no change in phase A physical property, is different for the solid, liquid and gaseous phase of the substance Appendix E,Specific Heat=,(amount of heat in J),(mass of substance in g)(temperature change in oC),Unit: J/goC,59,Example 1-20 Specific Heat How much heat s, in joules, is required to raise the temperature of 205g of water from 21.2oC to 91.4oC? amount of heat = (mass)(specific heat)(temperature change) amount of heat = (205g)(4.18J/goC)(91.4oC-21.2oC) = 6.02x104J (60.2kJ),Specific Heat=,(amount of heat ),(mass)(temperature change ),Exercise 58,59,60,Thermal equilibrium when two objects at different temperature are brought into contact, heat flow from the hotter to the colder body Reach to the same temperature endothermic = exothermic 吸熱 =放熱,Fig 1-23, p. 38,61,Example 1-21 Specific Heat A 588-gram chunk of iron is heated to 97.5oC. Then it is immersed in 247grams of water originally at 20.7oC. When thermal equilibrum has been reached, the water and iron are both at 36.2oC. Calculate the specific heat of iron. Temperature change of water = 36.2-20.7 = 15.5oC Temperature change of iron = 97.5-36.2 = 61.3oC Joules gained by water = Joules lost by iron Let x = specific heat of iron (247g)(4.18 J/goC)(15.5oC)=(588g)(x J/goC)(61.3oC) 16003.13 = 36044.4 x x = 0.444J/goC,Exercise 62,62,Example 1-22 Comparing Specific Heats We add the same amount of heat to 10.0grams of each of the following substances staring at 20oC: H2O(l); Hg(l); liquid Benzene,C6H6(l); and solid aluminum, Al(s). Rank the samples from lowest to highest final temperature. Refer to Appendix E fro required data. Substance specific heat H2O(l) 4.18 Hg(l) 0.138 C6H6(l) 1.74 Al(s) 0.90 amount of heat = (mass)(specific heat)(temperature change) specific heat : H2O(l) C6H6(l) Al(s) Hg(l) The ranking from the lowest to highest final temperature is H2O(l) C6H6(l) Al(s) Hg(l),Exercise 71,63,
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