专业英语,林卓佳 linzhjiamail.sysu.edu.cn,成绩：Quiz 30%，文献作业 20%，期末考试 50%,参考书： 1.化学化工专业英语 张裕平等编，化学工业出版社 2.化学化工专业英语 杨定桥等编，化学工业出版社,General Chemistry,Chapter 1,Numbers in Physical Quantities,1. Scientific Notation,The number of atoms in 12g carbon: 602,200,000,000,000,000,000,000,6.022 x 1023,N x 10n,N is a number between 1 and 10,n is a positive or negative integer,The mass of a single carbon atom in gram: 0.0000000000000000000000199,1.99 x 10-23 g,Pronounced: N times ten to the (power of) nth,32 is pronounced three squared, and 23 is two cubed.,2. Significant Figure,Significant Figures in a number include all the digits known with certainty, plus the first digit to the right that has an uncertain value.,Any digit that is not zero is significant 1.234 kg 4 significant figures Zeros between nonzero digits are significant 606 m 3 significant figures Zeros to the left of the first nonzero digit are not significant 0.08 L 1 significant figure If a number is greater than 1, then all zeros to the right of the decimal point are significant 2.0 mg 2 significant figures If a number is less than 1, then only the zeros that are at the end and in the middle of the number are significant 0.00420 g 3 significant figures,Units of Measurements,1. Systems of Measurements,2. Units of Measurements,Powers of ten are used for convenience with smaller or larger units in the SI system,Classification of Matter,Matter: anything that occupies space and has mass,Substance: a form of matter that has definite composition and distinct properties,Element: a substance that cannot be separated into simpler substances by chemical means,Compound: a substance composed of atoms of two or more elements chemically united in fixed proportions,Mixture: a combination of two or more substances in which they retain their distinct identities,Element,117 elements observed, of which 94 occur naturally on Earth Each element has a unique chemical symbol (one or two letters). Elements are building blocks of matter. The earths crust consists of 5 main elements. The human body consists mostly of 3 main elements,The next six elements are: N 3%, Ca 1.5%, P 1%, K, S, Na 0.75%,The next five elements are Na 2%, K 2%, Mg 2%, H 1%, Ti 0.5%,Periodic Table,Non-metal: Halogen and Chalcogen,Noble Gas,Rare Earth metal: Sc, Y, Ln,Elements and Their Symbols,Compounds,Most elements interact to form compounds. The proportions of elements in a compound is the same irrespective of how the compound was formed. Law of Constant Composition (Definite Proportions): all samples of a given chemical compound have the same elemental composition.,Physical and Chemical Changes,When a substance undergoes a physical change, its physical appearance changes, but its chemical nature does not. Physical changes do not result in a change of composition. When a substance changes its composition, it undergoes a chemical change.,