湖北省IGCSE培训机构,IGCSE化学词汇整理B

　　在学习IGCSE化学课程之前，未来小编建议同学们体现学习一些基本的IGCSE化学词汇，着能够帮助我们避免很多化学学习上的障碍，并且更好的进行知识点的学习和巩固。今天未来小编为大家准备了以B开头的部分IGCSE化学词汇，一起来了解一下吧！ 　　background radiation-radiation from external sources,typically from cosmic radiation and radioisotope decay. 　　back titration-titration in which the analyte concentration is determined by reacting it with a known quantity of excess reagent. 　　balanced equation-chemical equation in which the number and type of atoms and the electric charge is the same on both the reactant and product sides of the equation. 　　Balmer series-the part of the hydrogen emission spectrum for electron transitions n=2 and n>2,There are four lines in the visible spectrum. 　　barium-alkaline earth metal with element symbol Ba and atomic number 56. 　　barometer-instrument used to measure atmospheric pressure. 　　base-chemical species that either accepts protons or else donates electrons or hydroxide ions. 　　base anhydride(basic anhydride)-a metal oxide formed from the reaction between water and a basic solution. 　　base metal-any metal besides a precious or noble metal used for jewelry or in industry. 　　basic-alkaline or having a pH>7. 　　basic solution-aqueous solution containing more hydroxide ions than hydrogen ions;solution with pH>7. 　　Beer's law(Beer-Lambert Law)-law that states the concentration of a solution is directly proportional to its light absorbance. 　　berkelium-radioactive metal with element symbol Bk and atomic number 97. 　　beryllium-alkaline earth metal with element symbol Be and atomic number 4. 　　beta decay-type of radioactive decay that results in spontaneous emission of a beta particle. 　　beta particle-an electron or positron emitted during beta decay. 　　beta radiation-ionizing radiation from beta decay in the form of an energetic electron or positron. 　　binary acid-an acidic binary compound in which one element is hydrogen and the other element is another nonmetal. 　　binary compound-a compound made up of two elements(e.g.,HF). 　　binding energy-energy needed to remove an electron from an atom or to separate a proton or neutron from the atomic nucleus. 　　biochemistry-Biochemistry is the chemistry of living things. 　　bismuth-Bismuth is the name for the element with atomic number 83 and is represented by the symbol Bi.It is a member of the metal group. 　　bitumen-natural mixture of polycyclic aromatic hydrocarbons(PAHs). 　　black light-a lamp that emits ultraviolet radiation or the invisible radiation emitted by it. 　　block copolymer-copolymer formed by repeating monomer subunits. 　　bohrium-transition metal with element symbol Bh and atomic number 107. 　　boiling-phase transition from the liquid to gas state. 　　boiling point-temperature at which a liquid's vapor pressure is equal to the external gas pressure. 　　boiling point elevation-the increase in a liquid boiling point caused by adding another compound to it. 　　bond-a chemical link formed between atoms in molecules and molecules and ions in crystals. 　　bond angle-the angle formed between two adjacent chemical bonds within the same atom. 　　bond-dissociation energy-energy required to homolytically break a chemical bond. 　　bond energy-quantity of energy needed to break one mole of molecules into component atoms. 　　bond enthalpy-enthalpy change resulting when one mole of bonds in a species are broken at 298 K. 　　bond length-the equilibrium distance between atomic nuclei or groups of nuclei that share a chemical bond. 　　bond order-a measure of the number of electrons involved in chemical bonds between two atoms in a molecule;usually equal to the number of bonds between the atoms. 　　boron-Boron is the name for the element with atomic number 5 and is represented by the symbol B.It is a member of the semimetal group. 　　Boyle's law-ideal gas law that states the volume of a gas is inversely proportional to its absolute pressure,assuming constant temperature. 　　branched chain alkane-an alkane with alkyl groups bonded to the central carbon chain.The molecules are branched,but all C-C bonds are single bonds. 　　brass-Brass is defined as an alloy of copper and zinc. 　　bromine-Bromine is the name for the element with atomic number 35 and is represented by the symbol Br.It is a member of the halogen group. 　　Bronsted-Lowry acid-species that yields hydrogen ions. 　　Bronsted-Lowry base-species that accepts hydrogen ions in a reaction. 　　bronze-Bronze is an alloy of copper,usually containing tin as its main addition. 　　buffer-either a weak acid and its salt or else a weak base and its salt that form an aqueous solution that resists pH changes.