應(yīng)用化學(xué)專業(yè)英語(yǔ)翻譯

1、10級(jí)應(yīng)用化學(xué)（2）班 鄭祿春 B2010063224Lessen 24 Chemical ReactionsConservation of mass and energy（質(zhì)量與能量守恒）Two conservation laws（定律） apply to all chemical reactions: Energy can neither be created nor destroyed, and matter can neither be created nor destroyed. Thus the atoms taking part in a chemical reaction ma

2、y be rearranged, but all the atoms present in the reactants must also be present in the products, and the total mass of the reactants must equal the total mass of the products.化學(xué)反應(yīng)質(zhì)量守恒和能量守恒兩個(gè)守恒定律(定律)適用于所有的化學(xué)反應(yīng):能量既不能創(chuàng)造也不能消滅,物質(zhì)也不能創(chuàng)造也不能消滅。因此原子參與化學(xué)反應(yīng)可能重新安排,但所有的原子出現(xiàn)在反應(yīng)物必須包含在產(chǎn)品,反應(yīng)物的總質(zhì)量必須等于生產(chǎn)物的總質(zhì)量。What is

3、a chemical reaction?A chemical reaction occurs when substances (the reactants) collide (碰撞) with enough energy to rearrange to form different compounds (the products). The change in energy that occurs when a reaction take place is described by thermodynamics(熱力學(xué)）and the rate or speed at which a reac

4、tion occurs is described by kinetics (動(dòng)力學(xué)) . Reactions in which the reactants and products coexist are considered to be in equilibrium(處于平衡). A chemical equation consists of the chemical formula（化學(xué)式）of the reactants, and the chemical formula of the products. The two are separated by an usually read

5、as “yields” and each chemical formula is separated from others by a plus sign (加號(hào)) . Sometimes a triangle is drawn over the arrow symbol to denote energy must be added to the substances for the reaction to begin. Each chemical formula may be preceded by a scalar (數(shù)量的) coefficient indicating the prop

6、ortion (比例) of that substance necessary to produce the reaction in formula. For instance, the formula for the burning of methane(CH4 + 2O2 CO2 + 2H2O) indicates that twice as much O2 as CH4 is needed, and when they react, twice as much H2O as CO2 will be produced. This is because during the reaction

7、, each atom of carbon needs exactly two atoms of oxygen to combine with, to produce the CO2, and every two atoms of hydrogen need an atom of oxygen to combine with to produce the H2O. If the proportions of the reactants are not respected, when they are forced to react, either not all of the substanc

8、e used will participate in the reaction, or the reaction that will take place will be different from the one noted in the equation.什么是化學(xué)反應(yīng)一個(gè)化學(xué)反應(yīng)發(fā)生在物質(zhì)(反應(yīng)物)碰撞有足夠的能量去重新排列,形成不同的化合物(產(chǎn)品)。當(dāng)反應(yīng)發(fā)生時(shí)能量發(fā)生變化由熱力學(xué)描述，利率或速度進(jìn)行反應(yīng)發(fā)生是由動(dòng)力學(xué)描述。反應(yīng)中,反應(yīng)物和生成物共存被認(rèn)為是處于平衡。一個(gè)化學(xué)方程式包含反應(yīng)物的化學(xué)式和生成物的化學(xué)式。兩個(gè)化學(xué)式相距一個(gè)通常讀為“生成”,每個(gè)化學(xué)式與其它分開(kāi)是通過(guò)一個(gè)加

9、號(hào)。有時(shí)一個(gè)三角形繪制在箭頭符號(hào)上表示能量必須添加到物質(zhì)中這樣反應(yīng)才能開(kāi)始。每個(gè)化學(xué)公式可能前面有一個(gè)標(biāo)量(數(shù)量的)系數(shù)表明比例的物質(zhì)發(fā)生反應(yīng)有必要反應(yīng)在公式中。例如,這個(gè)公式燃燒甲烷(CH4 + 2O2CO2 + 2 H2O)表明兩倍的O2和一倍的CH4是必要的,而當(dāng)他們反應(yīng),兩倍的水會(huì)產(chǎn)生二氧化碳。這是因?yàn)樵诜磻?yīng)中,每個(gè)原子的碳需要完全的兩個(gè)原子氧結(jié)合,產(chǎn)生二氧化碳,每?jī)蓚€(gè)氫原子需要一個(gè)氧原子結(jié)合,產(chǎn)生水。如果反應(yīng)物的比例不受人的重視,當(dāng)他們被強(qiáng)制發(fā)生反應(yīng),要么不是所有的物質(zhì)將參與反應(yīng),那么就是發(fā)生的反應(yīng)不同于所標(biāo)記的化學(xué)反應(yīng)式。Balancing chemical equations（配

10、平化學(xué)方程式）A chemical equation must be balanced. That is, it must be written with the correct coefficients for each species participating so that for each element, the number of atoms in the reactants is the same as the number in the products. To balance an equation, it is often easiest to begin with at

11、oms that appear in only one formula on each side of the equation. It is also best to begin with the most complicated form The law of conservation of mass dictates the quantity of each element does notchange in a chemical reaction. Thus, each side of the chemical equation must represent the same quan

12、tity of any particular element Similarly, the charge is conserved in a chemical reaction. Therefore, the same charge must be present on both sides of the balanced equation.配平化學(xué)方程式一個(gè)化學(xué)方程式必須平衡。也就是說(shuō),它必須是書面上的系數(shù)符合每個(gè)物質(zhì)參與的反應(yīng),以便為每個(gè)元素的原子數(shù)的反應(yīng)物和生成物是一樣的數(shù)量。為了平衡方程,最簡(jiǎn)單的通常是從出現(xiàn)在只有一個(gè)公式兩邊的原子開(kāi)始。最好也是從結(jié)構(gòu)復(fù)雜的式子開(kāi)始。物質(zhì)守恒定律規(guī)定每

13、個(gè)元素的數(shù)量并不改變一個(gè)化學(xué)反應(yīng)。因此,兩邊的化學(xué)方程式必須代表相同數(shù)量的任何特定元素。同樣,電荷保存在一個(gè)化學(xué)反應(yīng)。因此,相同的電荷必須出現(xiàn)在平衡方程的兩邊。 One balances a chemical equation by changing the scalar number for each molecular formula. Simple chemical equations can be balanced by inspection, that is, by trial and error(通過(guò)反復(fù)試驗(yàn)).Another technique involves solving

14、a system of linear equations(線性方程).Example：Na+O2Na2O （1）對(duì)于每個(gè)分子公式平衡化學(xué)方程是通過(guò)改變標(biāo)量值。簡(jiǎn)單的化學(xué)方程式可以通過(guò)檢驗(yàn)得到平衡,也就是說(shuō),通過(guò)反復(fù)試驗(yàn)可以得到平衡。另一個(gè)技術(shù)包括求解一個(gè)線性方程組(線性方程)。例如:Na + O2Na2OIn order (for this equations)to be balanced, here must be an equal amount of Na on the left hand side as on the right hand side. As it stands now,

15、there is 1 Na on the left but 2 Nas on the right . This is solved by putting a 2 in front of the Na on the left hand side :2Na+O2Na2O （2）為了(對(duì)于這個(gè)方程)是平衡的,這里必須等量的Na在左邊和右邊。目前,有1 Na在左邊但2 Na在右邊。這是解決了通過(guò)將2在前面的Na左邊:2 Na + O2Na2OIn this case there are 2 Na atoms on the left and 2 Na atoms on the right .In the

16、 next step the oxygen atoms are balanced as well. On the left hand side there are 2 O atoms and the right hand side only has one . This is still an unbalanced equation .To fix this a 2 is added in front of the Na2O on the right hand side .Now the equation reads: 2Na+O22Na2O （3）在這種情況下,有2 Na原子在左邊和右邊2

17、Na原子。在下一步中,氧原子也是要平衡。左邊有2 O原子而右邊只有一個(gè)。這仍然是一個(gè)不平衡方程。要修復(fù)這個(gè)2添加在前面的Na2O右邊?，F(xiàn)在,方程式寫著:2 Na + O2 2Na2ONotice that the 2 on the right hand side is“distributed” to both the Na2 and the O .Currently the left hand side of the equation has 2 Na atoms and 2 O atoms .The right hand side has 4Na total and 2 O . There

18、must be an equal amount of each chemical on both sides . To fix this 2 more Na are added on the right left side . the equation will now look like this ：4Na+O22Na2O （4）注意,2在右手邊的是“分配”Na和O的。目前左側(cè)的方程有2個(gè)Na原子和2個(gè)O原子。右邊有4個(gè)Na和2個(gè)O。必須有等量的每個(gè)化學(xué)兩邊。要修復(fù)這個(gè)2個(gè)Na被添加在右邊的左邊。這個(gè)方程,將現(xiàn)在看起來(lái)像這樣: 4Na +O22Na2OThis equation is a b

19、alanced equation because there is an equal number of atoms of each element on the left and right hand sides of the equation .Example:P4+O22P2O5 （5）This equation is not balanced because there is an unequal amount of o on both sides of the equation . The left hand side has 4 P and the right hand side

20、has 4 P .So the P atoms are balanced . the left hand side has 2 O and the right hand side has 10 O.這個(gè)方程是一個(gè)平衡方程,因?yàn)橛型葦?shù)量的每個(gè)元素的原子在方程的左邊和右邊。例如:P4 + O22P205這個(gè)方程是不平衡的,因?yàn)橛幸粋€(gè)不平等的數(shù)量的O在方程的兩邊。左手邊有4 p而右邊有4 p。所以p原子是平衡的。左手邊有2個(gè)O而右邊有10個(gè)O。To fix this unbalanced equation a 5 in front of the O2 on the left hand side i

21、s added to make 10 O on both sides resulting in P4+5O22P2O5 （6）The equation is now balanced because there is an equal amount of substances on the left and the right hand side of the equation .要修復(fù)這個(gè)不平衡方程O2前面的5是左邊的補(bǔ)充,使兩邊都有10個(gè)O則有P4 + 5O22 P2O5這個(gè)方程現(xiàn)在平衡,因?yàn)橛械攘康奈镔|(zhì)在方程的左邊和右邊。The balancing of chemical equatio

22、ns is a common exercise in elementary stoichiometry(基礎(chǔ)化學(xué)計(jì)量法). It is not always appreciated ,however, that some chemical equations are ambiguous(不明確的) in that they can be balanced in more than one way . Consider, for example, H+ +ClO3- +Cl-Cl2+ClO2+H2O,where the dashed arrow signifies an unbalanced e

23、quation. It may be balanced as follows:4H+ +2ClO3- +2Cl-Cl2+2ClO2+2H2O在基本化學(xué)計(jì)量學(xué)平衡化學(xué)方程式是一種常見(jiàn)的操作 。它并不總是,然而,一些化學(xué)方程不明確的,它們可以平衡的方法不止一種?？紤],例如,H+ + ClO3- +Cl-Cl2 +ClO2+H2O,虛線箭頭表示一個(gè)不平衡方程。它可以平衡如下:4H+ + 2ClO3- +2Cl-Cl2+2ClO2+2H2OBoth sides of this equation have four H-atoms, six O-atoms, four CL-atoms, and a t

24、otal charge of zero . It can also be balanced as:16H+ + 4CLO3- +12CL- = 7CL2 + 2CLO2 + 8H2O (8)Here both sides have 16 H-atoms, 12O-atoms, 16 Cl-atoms , and a total charge of zero. How can both equations balance ,and which is correct? To answer the first question, many equations can be written as th

25、e sum of two or more component reactions .In this case the following related reaction can be used:8H+ + 2ClO2 +8Cl- = 5Cl2 +4H2O (9)Deciding which equation is “correct” is often difficult because one of many competing pathways may take precedence (優(yōu)先) in a reaction, depending on the energy requireme

26、nts of the system(the thermodynamic limitations) and the speed of the reactions (the kinetics of the system).In the example above ,analysis shows that equation(7) is thermodynamically unfavorable at room temperature while equation(8) is favorable.這兩方面的平衡有4個(gè)氫原子,6個(gè)氧原子,4個(gè)氯原子,且總電荷為零。它也可以這樣平衡:16H+ + 4ClO

27、3- + 12Cl- = 7CL2 + 2CLO2 + 8H20,這里雙方都有16個(gè)氫原子,12 氧原子,16 氯原子,和總電荷為零。如何平衡兩邊的化學(xué)式,哪個(gè)是正確的呢?回答第一個(gè)問(wèn)題,許多方程可以寫成兩個(gè)或多個(gè)的組成反應(yīng)。在這種情況下,可以使用以下相關(guān)反應(yīng):8H+ + 2ClO2+ 8cl- = 5Cl2 + 4H2O決定哪些方程是“正確的”通常是困難的,因?yàn)樵谝粋€(gè)反應(yīng)許多相互競(jìng)爭(zhēng)的途徑之一可能需要優(yōu)先,這取決于系統(tǒng)的能量需求(熱力學(xué)限制)和反應(yīng)的速度(動(dòng)力學(xué)的系統(tǒng))。在上面的例子中,分析表明,方程(7)是在室溫不宜加熱。Some types of chemical reactions (

28、化學(xué)反應(yīng)的幾個(gè)類型)In a combination reaction (化合反應(yīng)), two reactants combine to give a single product , i . e ,A + BAB.Example: 2H2O+O22H2O; C+O2CO2.When two elements react ,a combination reaction occurs producing a binary compound(二元化合物)（that is, one consisting of only two types of atoms）.If a metal and a non

29、metal react, the product is ionic with a formula determined by the charges on the ions the elements form. If two nonmetals react ,the product is a molecule with polar covalent bonds, with a formula consistent with the normal valences of the atoms involved.化學(xué)反應(yīng)的幾個(gè)類型在一個(gè)組合反應(yīng)(化合反應(yīng)),兩個(gè)反應(yīng)物的結(jié)合給予一個(gè)單一產(chǎn)品,比如，A

30、 + BAB。例如:2H2+O22H2O;C+O2CO2。當(dāng)兩個(gè)元素發(fā)生反應(yīng),結(jié)合反應(yīng)發(fā)生產(chǎn)生一個(gè)二元化合物(一個(gè)只有兩種類型的原子)。如果一個(gè)金屬和非金屬反應(yīng),該產(chǎn)品的離子方程式?jīng)Q定于離子形式的元素。如果兩個(gè)非金屬反應(yīng),該產(chǎn)品是一種分子極性共價(jià)鍵,用一個(gè)公式符合正常的原子的特征有關(guān)。In a decomposition reaction (分解反應(yīng)),a single compound breaks down to give two or more other substances. i.e, ABA+BExample:2H2O2H2+O2; 2HgO2Hg+O2Reaction of a

31、metal oxide with water produces a metal hydroxide;that is ,a strong base. Reaction of a nonmetal oxide with water produces an oxyacid(含氧酸)in which the nonmetal is in the same oxidation state as in the oxide you started with.在分解反應(yīng),單個(gè)化合物分解給兩個(gè)或兩個(gè)以上的其他物質(zhì)。如,ABA + B例如:2 H2O2H2 + O2;2HgO2Hg + O2反應(yīng)的金屬氧化物與水產(chǎn)

32、生一個(gè)金屬氫氧化物;那就是強(qiáng)堿。反應(yīng)的非金屬氧化物與水產(chǎn)生一種含氧酸,非金屬是在同一個(gè)氧化態(tài)的氧化物開(kāi)始。Both of these are combination reactions, and both can be reversed by heating the products. Metal hydroxides decompose on heating to give the metal oxide and water. Oxyacids decompose on heating to give water and the nonmetal oxide in the appropria

33、te oxidation state.這兩種是結(jié)合反應(yīng),都是可以逆轉(zhuǎn)的加熱的產(chǎn)物。金屬氫氧化物加熱分解成金屬氧化物和水。含氧酸在適當(dāng)?shù)难趸瘧B(tài)加熱分解成水和非金屬氧化物。In a displacement reaction（置換反應(yīng)）,atoms or ions of one substance replace other atoms or ions in a compound (A+BCAC+B).Metals can be arranged in an activity series based on their ability to displace hydrogen from water

34、 or acids and their ability to displace hydrogen from water or acids and their ability to displace each other in soluble ionic compounds. Zinc metal reacts with aqueous hydrochloric acid to happen a displacement reaction.Zn(s)+HCl(aq)ZnCl2+H2(g)在一個(gè)置換反應(yīng),原子或離子的其中一個(gè)物質(zhì)取代其他的化合物的原子或離子 (A+BCAC+B)。金屬可以安排在一個(gè)

35、活動(dòng)系列基于他們從水或酸取代氫的能力和他們?cè)谌茈x子化合物互相取代的能力。鋅金屬與鹽酸水溶液反應(yīng)發(fā)生一個(gè)位移反應(yīng)。Zn(s)+ HCl(aq)ZnCl2 + H2(g)Partner exchange(double decomposition, double displacement, and metathesis)reaction (復(fù)分解反應(yīng))have the general form AC+BDAD+BC. Often such reactions occur between ionic compounds in solution when one product is an insolu

36、ble solid ,known as a precipitate.Example:AgNO3(aq)+NaCL(s)AgCL(s)+NaNO3(aq)復(fù)分解反應(yīng)有這樣的通式AC+BDAD+BC，當(dāng)一個(gè)產(chǎn)品是一種不溶性固體通常這種反應(yīng)發(fā)生在溶液中離子化合物之間,稱為沉淀。例如:AgNO3(aq)+NaCl(s)AgCL(s)+ NaNO3(aq)Acid-base reactions(酸堿反應(yīng))The Bronsted-Lowry definition describes acids as proton donors and bases as proton acceptors. Acids a

37、nd bases can react with water and also react together . An acid in water will dissociate and a base will undergo hydrolysis (水解) ,which means that it splits a water molecule. The acid dissociation and base hydrolysis reactions are described in the acid-base equilibrium document.The reaction of an ac

38、id and a base is called a neutralization (中和) reaction. Mixing acids and bases results in neutralization because the base will accept the proton that the acid donates. What remains when an acid and base react depends on the relative amounts of the acid and base.The following example shows neutraliza

39、tion of equal molar quantities of a strong acid and a strong base.HNO3+NaOHH2O(l)+Na(aq)+NO3(aq)The spectator ions are usually left out of the reaction and the “net” reaction is:H+(aq)+OH-(aq)H2O(l)酸堿反應(yīng)布侖斯惕lowry的定義描述了酸作為質(zhì)子供體和堿作為質(zhì)子受體。酸和堿可以與水反應(yīng)也能反應(yīng)在一起。一個(gè)酸在水中會(huì)分離而一個(gè)堿將進(jìn)行水解,這意味著它可以將一個(gè)水分子分離。在分解文檔中把酸堿分解反應(yīng)歸在

40、酸堿平衡。酸和堿的反應(yīng)稱為中和反應(yīng)。將酸和堿混合會(huì)發(fā)生中和因?yàn)閴A將接受質(zhì)子,酸提供質(zhì)子。剩下的,酸和堿的反應(yīng)取決于相對(duì)數(shù)量的酸和堿。下面的例子顯示了中和同等的摩爾量的強(qiáng)酸和強(qiáng)堿。HNO3+NaOHH2O(l)+ Na+(aq)+ NO3-(aq)沒(méi)有參與反應(yīng)的離子通常排除在反應(yīng)外，“中心”反應(yīng)是:H+(aq)+OH-(aq)H2O(l)Precipitation reaction(沉淀反應(yīng))Many compounds have limited solubility in aqueous(water)solution. When the concentrations of the ions i

41、n a solution rise above the solubility limit, the ions combine to form solid particles that precipitate from solution. The concentrations of the ions remaining in solution are governed by the equilibrium constant,Ksp, which is called the solubility product.Example: When chloride is added to a silver

42、 solution, solid silver chloride precipitates from solution. The resulting equilibrium is always written in the direction of the solid dissolving:AgCL(s)=Ag+(aq)+Cl-(s)沉淀反應(yīng)許多化合物的溶解度有限于水的。當(dāng)濃度的離子在溶液中溶解度超越極限,離子結(jié)合,形成固體顆粒沉淀,從解決方案。剩余的離子的濃度在解決方案是由平衡常數(shù),生長(zhǎng)稱為溶度積。例如:當(dāng)氯添加到一個(gè)銀溶液,固體氯化銀沉淀物從解決方案。由此產(chǎn)生的平衡總是寫在固體溶解的方向:

43、AgCL(s)= Ag+(aq)+ Cl-(s)Complexation reactions(配位反應(yīng))Metal ions in solution can bind with ligands to form soluble complexes. These reactions are always described by the equilibrium expression written in the direction of complex formation. The equilibrium constant, Kf, is called the formation constant

44、.Example: When ethylenediaminetetraacetic acid(EDTA)is added to a solution containing calcium ion a calcium(EDTA) complex forms in solution:Ca2+(aq)+EDTA(aq)=Ca(EDTA)(aq)配位反應(yīng)金屬離子在溶液中可以綁定與配體形成可溶性復(fù)合物。這些反應(yīng)總是描述平衡表達(dá)式寫在復(fù)雜地層的方向。平衡常數(shù)、Kf,稱為形成常數(shù)。例如:當(dāng)乙二胺四乙酸(EDTA)添加到一個(gè)解決方案包含鈣離子鈣(EDTA)復(fù)雜的形式在解決方案:Ca(aq)+ EDTA(aq)

45、= Ca(EDTA)(aq)Redox reactions (氧化還原反應(yīng))Reduction-oxidation(redox) reactions involve the transfer of electrons from one species to another. One species will be oxidized and the other will be reduced.Example: Zn(s)+Cu(aq)Zn(aq)+Cu(s)In this reaction two electrons are transferred from each znic atom to

46、each copper ion. The zinc metal is oxidized to zinc ions and the copper ions are reduced to copper metal.氧化還原反應(yīng)還原氧化(氧化還原反應(yīng))涉及電子從一個(gè)物種轉(zhuǎn)移到另一個(gè)。一個(gè)物種將氧化而其他將減少。例如:鋅(s)+銅(aq)鋅(aq)+銅(s)在這兩個(gè)電子轉(zhuǎn)移反應(yīng)從每個(gè)Zn原子到每Cu離子。鋅金屬被氧化成鋅離子而銅離子被還原成銅金屬。Net ionic equations(離子方程)Ions that are present during a reaction in aqueous so

47、lution but undergo no chemical change are called spectator ions. A net ionic equation shows only the species involved in a chemical change, excluding spectator ions. In such an equation charge must always be conserved; the sum of the charges on the left must equal the sum of the charges on the right

48、. An ionic equation is a chemical equation in which electrolytes are written as dissociated ions. Ionic equations are used for single and double displacement reactions which occur in aqueous solutions. For example in the following precipitation reactions:CaCL2(aq)+2AgNO3(aq)Ca(NO3)2(aq)+2AgCL(s)The full ionic equation would be:Ca2+ +2CL- +2Ag+ +2NO3-Ca2+ +2NO3- +2AgCL(s)And the