edexcel-as-chemistry-vocabulary

1、1 Formulae, equations and amounts of substance1.1 The foundations of chemistry1. FormulaeA chemical formula is a way of expressing information about the proportions of atoms that constitute a particular chemical compound, using a single line of chemical element symbols, numbers, and sometimes also o

2、ther symbols, such as parentheses, dashes, brackets, and plus (+) and minus () signs.2. EquationA chemical equation is the symbolic representation of a chemical reaction wherein the reactant entities are given on the left-hand side and the product entities on the right-hand side3. Amount4. Substance

3、A chemical substance is a form of matter that has constant chemical composition and characteristic properties. It cannot be separated into components by physical separation methods, i.e. without breaking chemical bonds. It can be solid, liquid, gas, or plasma.5. AtomThe atom is a basic unit of matte

4、r that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons.6. Observation Observation is the active acquisition of information from a primary source.7. Experiment An experiment is an orderly procedure carried out with the goal of verifying, refuting, or establis

5、hing the validity of a hypothesis.8. Periodic TableThe periodic table is a tabular arrangement of the chemical elements, organized on the basis of their atomic numbers (numbers of protons in the nucleus), electron configurations, and recurring chemical properties.9. NucleusThe nucleus is the very de

6、nse region consisting of protons and neutrons at the center of an atom.10. ProtonThe proton is a subatomic particle with the symbol p or p+ and a positive electric charge of 1 elementary charge.11. NeutronThe neutron is a subatomic particle that has the symbol n or n0. Neutrons have no net electric

7、charge and a mass slightly larger than that of a proton12. ElectronThe electron (symbol: e) is a subatomic particle with a negative elementary 推荐精选electric charge.13. ElementA chemical element is a pure chemical substance consisting of a single type of atom distinguished by its atomic number, which

8、is the number of protons in its atomic nucleus. Elements are divided into metals, metalloids, and nonmetals.14. Atomic numberThe atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, and therefore identical to

9、the charge number of the nucleus.15. Mass numberThe mass number (A), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus.16. SymbolA chemical symbol is a 1-, 2-, or 3-letter internationally agreed code for a

10、chemical element, usually derived from the name of the element, often in Latin. Only the first letter is capitalized.17. IsotopeIsotopes are variants of a particular chemical element such that, while all isotopes of a given element have the same number of protons in each atom, they differ in neutron

11、 number.18. PropertyProperty is that which belongs to or with something, whether as an attribute or as a component of said thing.19. StableStable means when a system is in its lowest energy state, or chemical equilibrium with its environment. 推荐精选1.2 Formulae and equations09.03.201420

12、. Ionic bonding (bond) Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions.In the simplest case, the cation is a metal atom and the anion is a nonmetal atom, but these ions can be of a more complex nature, e.g. molecular ions like NH4+

13、or SO42-21. Covalent bonding (bond)A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding.22. IonAn ion is an atom or molecule in which th

14、e total number of electrons is not equal to the total number of protons, giving the atom a net positive or negative electrical charge.23. Balanced equationOne balances a chemical equation by changing the scalar number for each chemical formula.24. Spectator ions旁观离子25. Overall ionic equation Or Net

15、ionic equation净离子方程式26. Elements:Zn: ZincH: HydrogenAl: AluminumLi: LithiumSi: Silicon Cu: CooperAg: SilverU: UraniumNa: SodiumCl: ChlorineO: OxygenMg: MagnesiumN: Nitrogen推荐精选1.3 How big and heavy are atoms? 09.10.201427. MoleculeA molecule is an electrically neutral group of two or more atoms held

16、 together by chemical bonds28. Relative atomic massThe relative atomic mass of an element is defined as the average mass of its isotopes compared with the mass of an atom of the carbon-12 isotopes29. Relative atomic mass scaleThe scale by which chemists compare the mass of all atoms to the mass of a

17、 carbon-12 isotopes.30. Weighted mean 加权平均值The weighted mean is similar to an arithmetic mean (算术平均值) (the most common type of average), where instead of each of the data points contributing equally to the final average, some data points contribute more than others.31. Elements:Br: bromineC: carbon

18、Fe: iron推荐精选1.4 The mole 09.12.201432. MoleA mole of any substance is defined as the amount of substance that contains as many particles (atoms, ions or molecules) as there are atoms in exactly 12g of carbon-12.33. Avogadro constantThe Avogadro constant has the unit particles per mole (mol-1). L or

19、NA34. Molar massMolar mass is just the numerical value of the relative atomic mass, g/mol35. SI unitThe International System of Units (abbreviated SI from French: Le Système international d'unités) is the modern form of the metric system and is the world's most widely used system o

20、f measurement, used in both everyday commerce and science.36. SI base unitThe base SI units are the metre (m), the kilogeam (kg), the second (s), the ampere (A), the Kelvin (K), the candela (cd), and the mole (mol).37. SI derived unitDerived units are formed by powers, products or quotients of the b

21、ase units and are unlimited in number. 1.5 using moles36. Relative formula massThe sum of the relative atomic masses of all the atoms in the chemical formula. 37. Relative molecular mass (Mr)Relative formula mass in covalent compounds.38. Molar massMolar mass is the relative molecular formula mass i

22、n grams per mole39. Avogadros lawEqual volumes of all gases contain equal numbers of molecules, provided that they are at the same temperature and pressure. And when the gas is in the standard temperature and pressure (STP), I mol of any gas is 24 dm3 or 24L. 40. Molar volumeOne mole of any gas must

23、 occupy the same volume under the same conditions, Vm. For example, in STP conditions. 推荐精选1.6 Calculating formulae using moles 09.17.201441. Empirical formula Simplest formula of a compound showing the whole number ratios of the atoms42. Molecular formula Formula of a compound showing how many of e

24、ach atom there are1.7 Measuring concentration43. SolutionA solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is a substance dissolved in another substance, known as a solvent.44. Concentration Measure of the amount of a solute dissolved in a solvent to form a

25、solution.45. Molar solutionA solution of concentration 1 molar (1 mol/dm3)46. Volumetric flask (量瓶)47. Methodology(方法论)48. Creatinine肌酐(creatinine，Cre)是肌肉在人体内代谢的产物，每20g肌肉代谢可产生1mg肌酐。肌酐主要由肾小球滤过排出体外。血中肌酐来自外源性和内源性两种，外源性肌酐是肉类食物在体内代谢后的产物；内源性肌酐是体内肌肉组织代谢的产物。在肉类食物摄入量稳定时身体的肌肉代谢又没有大的变化，肌酐的生成就会比较恒定。49. Urea 尿素，

26、又称碳酰胺（carbamide)，是一种白色晶体。最简单的有机化合物之一。碳酸的二酰胺，分子式为H2NCONH2（CO(NH2)2）。哺乳动物和某些鱼类体内蛋白质代谢分解的主要含氮终产物。也是目前含氮量最高的氮肥。作为一种中性肥料，尿素适用于各种土壤和植物。它易保存，使用方便，对土壤的破坏作用小，是目前使用量较大的一种化学氮肥。工业上用氨气和二氧化碳在一定条件下合成尿素。推荐精选1.7 other units of concentration 50. percentage In mathematics, a percentage is a number or ratio expressed a

27、s a fraction of 100.51. ppm: parts per millionppm (parts-per-million, 106), ppb (parts-per-billion, 109), ppt (parts-per-trillion, 1012) and ppq (parts-per-quadrillion, 10-15).1.8 more ways to calculate equations52. precipitation Precipitation is the creation of a solid in a solution or inside anoth

28、er solid during a chemical reaction or by diffusion in a solid.53. titrateTitration is a common laboratory method of quantitative chemical analysis that is used to determine the unknown concentration of an identified analyte.54. Centrifuge 离心机推荐精选2 Energetics and enthalpy changes 09.29.20142.1 Energ

29、etics and enthalpy changes2.2 Measuring energy changes enthalpy change1. EnergeticsEnergetics is the study of energy transfers between reacting chemicals and their surroundings.2. Thermochemistry热化学The study of energy transfers in chemistry3. Endothermic and exothermicA reaction that needs energy fr

30、om heating to take place is endothermicA reaction that releases energy as heat is exothermic4. Neutralization reactionsNeutralization reactions are reactions between acids and alkalis.5. Enthalpy焓The energy content of a system held at constant pressure is enthalpy, represented by the letter H.6. Pho

31、tosynthesisIt is the process by which plants make glucose (C6H12O6) and oxygen from carbon dioxide and water using energy from the sun. It is an endothermic reaction. 7. SystemSystem is where the enthalpy changes happen.8. SurroundingsOutside the system, everything else is known as the surroundings.

32、9. BoundaryBoundary separates the system from its surroundings. 10. Dissipate分散11. Principle of conservation of energyThe total energy content of the universe is constant.2.3 Measuring energy changes enthalpy change 12. Enthalpy changeThe change in the energy content of a system held at constant pre

33、ssure.13. Diagram 图标，图解推荐精选2.4 Heat capacities and calorimeters14. Heat capacity CHeat capacity of an object (or a body of liquid or air) is the amount of heat required to raise its temperature by 1K. The SI unit of heat capacity is joule per kelvin, J K-115. Specific heat capacity cIt is the amount

34、 of energy in joules (J) needed to raise the temperature of one kilogram (kg) of a particular substance by 1 kelvin (K)16. Kelvin and CelsiusT(K)=273.15+t(oC)17. CalorimeterIt is insulated container used to measure enthalpy change of a reaction. 18. Apparatus 仪器19. Thermometer温度计20. Spirit burner酒精灯

35、21. Standard enthalpy changeAn enthalpy change measured under 1 atm pressure and 298K (25oC) is called Standard Enthalpy change. Allow to compare how much energy is given out or taken in at constant pressure by different reactions. Conditions： Temperature and pressure States: Normal physical states

36、under the standard condition Amount of substance: Per mol or Where solutions are used, 1 mol dm-32.5 Important enthalpy change22. Fraction 分数23. Completely burnt 完全燃烧24. Combustion Combustion or burning is a high-temperature exothermic chemical reaction between 推荐精选a fuel an

37、d an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed smoke. 25.26. Formation reactionA formation reaction is a reaction where the one mole of product is formed.27. Atomization reaction28. Standard enthalpy change of combust

38、ionThe enthalpy change when one mole of a substance is completely burnt in oxygen under standard conditions. 29. Standard enthalpy change of formationIt is the enthalpy change when one mole of the compound is formed from its elements under standard conditions. 30. Standard enthalpy change of atomizationThe standard enthalpy change of atomisation of an element is the enthalpy change when one mole of its atoms in the gaseous state is formed from its element under standard conditions.3