AP化学词汇（五）

　　对于中国学生来说，一门优秀的AP成绩不仅对学生的申请有所帮助，还能为以后融入美国的学习生活打下基础。对于学习AP的同学来说，掌握词汇是至关重要的，词汇量不足将对答题速度和对标题理解都会影响。新东方在线AP盘点了各科目的词汇，今天为大家带来的是：AP化学词汇(五)，建议同学们收藏。

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　　AP化学词汇(五)

　　ideal gas constant

　　理想气体常数

　　The ideal gas constant is also known as the universal gas constant or the molar gas constant or simply the gas constant, denoted as R. The dimension

　　of the gas constant is expressed in energy per unit mole per unit temperature.The value of the gas constant in SI unit is 8.314 J mol−1 K−1. The gas constant has the same unit as of entropy and molar heat capacity.

　　Kelvin temperature

　　开尔文温度

　　The kelvin is a unit of measure for temperature based upon an absolute scale.It is one of the seven base units in the International System of Units (SI) and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all thermal motion ceases in the classical description of thermodynamics.

　　Dalton’s Law of

　　Partial Pressures

　　道尔顿分压定律

　　In chemistry and physics, Dalton's law (also called Dalton's law of partial pressures) states that in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases.

　　Non-Ideal Gases

　　非理想气体

　　An ideal gas is a theoretical idea – a gas in which there are no attractive forces between the molecules, and in which the molecules take up no space.But both of these assumptions are incorrect in the real world. All gases in the real world have molecules with diameters and which interact with each other, so there's always a bit of error involved in using any form of the Ideal Gas Law.

　　van der Waals

　　equation

　　范德华方程

　　The van der Waals equation (or van der Waals equation of state) is an equation relating the density of gases and liquids (fluids) to the pressure (p), volume (V), and temperature (T) conditions (i.e., it is a thermodynamic equation of state).

　　carbon monoxide

　　一氧化碳

　　Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air.

　　effuse

　　扩散 v.

　　Give off (a liquid, light, smell, or quality).

　　graduated cylinder

　　量筒

　　A graduated cylinder, measuring cylinder or mixing cylinder is a common piece of laboratory equipment used to measure the volume of a liquid. It has

　　a narrow cylindrical shape. Each marked line on the graduated cylinder represents the amount of liquid that has been measured.

　　absolute

　　temperature

　　绝对温度

　　A temperature measured from absolute zero in kelvins.

　　Graham’s law of

　　effusion

　　格拉汉姆气体扩散

　　定律

　　Graham's law of effusion (also called Graham's law of diffusion) was formulated by Scottish physical chemist Thomas Graham in 1848. Graham found experimentally that the rate of effusion of a gas is inversely proportional to the square root of the mass of its particles.

　　molar mass

　　摩尔质量

　　In chemistry, the molar mass M is a physical property defined as the mass of a given substance (chemical element or chemical compound) divided by its

　　amount of substance. The base SI unit for molar mass is kg/mol. However, for historical reasons, molar masses are almost always expressed in g/mol.

　　homogeneous

　　同质的 adj.

　　A Homogeneous mixture is a solid, liquid or gaseous mixture that has the same proportions of its components throughout a given sample.

　　colloid

　　胶体

　　A homogeneous noncrystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second

　　substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

　　heterogeneous

　　异质的 adj. In chemistry, a heterogeneous mixture consists of either or both of a) multiple states of matter or b) hydrophilic and hydrophobic substances in one mixture; an example of the latter would be a mixture of water,octane,and silicone grease.

　　micrometer

　　千分尺

　　A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of

　　components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial,vernier, and digital calipers.

　　chromatography

　　层析

　　Chromatography is the collective term for a set of laboratory techniques for the separation of mixtures. The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase. The various constituents of the mixture travel at different speeds, causing them to separate.

　　intermolecular force

　　分子间作用力

　　Intermolecular forces are the forces which mediate interaction between molecules, including forces of attraction or repulsion which act between

　　molecules and other types of neighboring particles, e.g., atoms or ions.Intermolecular forces are weak relative to intramolecular forces – the forces which hold a molecule together. For example, the covalent bond, involving sharing electron pairs between atoms, is much stronger than the forces present between neighboring molecules.

　　component

　　组成部分

　　A part or element of a larger whole.

　　distillation

　　蒸馏

　　Distillation is a process of separating the component substances from a liquid mixture by selective evaporation and condensation. Distillation may

　　result in essentially complete separation (nearly pure components), or it may be a partial separation that increases the concentration of selected components of the mixture.

　　condenser

　　冷凝器

　　An apparatus or container for condensing vapor.

　　permanent dipole

　　永久偶极矩

　　A permanent dipole is created in a molecule when there is an electronegative atom, such as oxygen, nitrogen or a halogen. The permanent dipole consists of regions of partial positive charge and regions of partial negative charge within the same molecule.

　　hydrogen bonding

　　氢键

　　A hydrogen bond is the electrostatic attraction between polar groups that occurs when a hydrogen (H) atom bound to a highly electronegative atom

　　such as nitrogen (N), oxygen (O) or fluorine (F) experiences attraction to some other nearby highly electronegative atom.

　　melting point

　　熔点

　　Melting point, temperature at which the solid and liquid forms of a pure substance can exist in equilibrium. As heat is applied to a solid, its

　　temperature will increase until the melting point is reached. More heat then will convert the solid into a liquid with no temperature change.

　　sublimation

　　升华

　　Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase. Sublimation is an endothermic process that occurs at temperatures and pressures below a substance's triple point in its phase diagram, which corresponds to the lowest pressure at which the substance can exist as a liquid. The reverse process of sublimation is deposition or desublimation, in which a substance passes directly from a gas to a solid phase.

　　dipole

　　偶极

　　A dipole is a separation of electrical charges. In chemistry, a dipole refers to the separation of charges within a molecule between two covalently bonded atoms.

　　London dispersion

　　force

　　伦敦色散力

　　London dispersion forces (LDF, also known as dispersion forces, London forces, instantaneous dipole–induced dipole forces, or loosely van der Waals forces) are a type of force acting between atoms and molecules. They are part of the van der Waals forces. The LDF is named after the German-American physicist Fritz London.

　　temporary dipole

　　瞬时偶极

　　Temporary dipoles are when the electron clouds' density around a nucleus shifts in density, forming temporary dipoles. This is to say that the concentration of electrons are more concentrated in one part of a molecul than anywhere else.

　　straight-chain

　　直链的

　　A chain of atoms in a molecule, usually carbon atoms, that is neither branched nor formed into a ring.

　　electronegative

　　负电性的 adj。

　　(of an element) Tending to acquire electrons and form negative ions in chemical reactions

　　three-dimensional

　　3D 立体的 Having or appearing to have length, breadth, and depth.

　　capillary action

　　毛细作用

　　Capillary action (sometimes capillarity, capillary motion, or wicking) is the ability of a liquid to flow in narrow spaces without the assistance of, or even in opposition to, external forces like gravity.

　　miscible

　　互溶的 adj.

　　(of liquids) forming a homogeneous mixture when added together

　　soluble

　　溶解的 adj.

　　(of a substance) Able to be dissolved, especially in water.

　　deviations

　　偏差

　　The amount by which a single measurement differs from a fixed value such as the mean.

　　hydrophobic

　　疏水的 adj.

　　In chemistry, hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is seemingly repelled from a mass of water.(Strictly

　　speaking, there is no repulsive force involved; it is an absence of attraction.)

　　In contrast, hydrophiles are attracted to water.

　　hydrophilic

　　亲水的 adj.

　　Tending to dissolve in, mix with, or be wetted by water: a hydrophilic colloid. The opposite of hydrophobic.

　　catalyze

　　催化 v.

　　Cause or accelerate (a reaction) by acting as a catalyst.

　　Enzyme

　　酶

　　Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life

　　covalent bonding

　　共价键

　　Covalent bond, in chemistry, the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the

　　electrostatic attraction of their nuclei for the same electrons.

　　polyatomic

　　多原子的

　　A polyatomic ion is an ion consisting of multiple atoms associated together by covalent bonds which can be considered as acting as a single unit in the context of acid/base chemistry or in the formation of salts.

　　polarity

　　极性

　　In chemistry, polarity is a separation of electric charge leading to a molecule or its chemical groups having an electric dipole or multipole moment. Polar molecules must contain polar bonds due to a difference in electronegativity between the bonded atoms.

　　electron pair

　　电子对

　　In chemistry, an electron pair or a Lewis pair consists of two electrons that occupy the same molecular orbital but have opposite spins. The electron pair concept was introduced in a 1916 paper of Gilbert N. Lewis.

　　oxidation number

　　氧化数

　　Oxidation number, also called Oxidation State, the total number of electrons that an atom either gains or loses in order to form a chemical bond with

　　another atom.

　　bond strength

　　键强度

　　In chemistry, bond energy (E) or bond enthalpy (H) is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond dissociation energies (usually at a temperature of 298 K) for all bonds of the same type within the same chemical species.

　　bond length

　　键长

　　In molecular geometry, bond length or bond distance is the average distance between nuclei of two bonded atoms in a molecule. It is a transferable

　　property of a bond between atoms of fixed types, relatively independent of the rest of the molecule.

　　bond energy

　　键能

　　In chemistry, bond energy (E) or bond enthalpy (H) is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond dissociation energies (usually at a temperature of 298 K) for all bonds of the same type within the same chemical species.

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