Chapter 14 Chemical Equilibrium

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1 Chapter 14 Chemical Equilibrium
Chemistry English 99-2 Semester

2 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
Vocabulary and Phrase 字與詞 Equilibrium Equilibria Chemical Equilibrium Physical Equilibrium 平衡 平衡 (複數) 化學平衡 物理平衡

3 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
Definition and Reading 定義與例句閱讀 Chemical Equilibrium 化學平衡 Chemical equilibrium is achieved when the rates of the forward and reverse reactions are equal and the concentrations of the reactants and products remain constant.

4 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
Chemical equilibrium is achieved when the rates of the forward and reverse reactions are equal and the concentrations of the reactants and products remain constant. achieve forward reverse remain 達到 正向的 逆向的 保持 中譯: 當正反應與逆反應的速率相等而反應物濃度與產物濃度不再變化時即達到化學平衡(的狀態) 。

5 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
Definition and Reading 定義與例句閱讀 Physical Equilibrium 物理平衡 Equilibrium between two phases of the same substance is called physical equilibrium because the changes that occur are physical processes.

6 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
Equilibrium between two phases of the same substance is called physical equilibrium because the changes that occur are physical processes. phase between occur process(es) 相 在…之間 發生 程序 中譯: 相同物質兩個相之間的平衡稱為物理平衡，因為所發生的變化是物理程序。

7 The Equilibrium Constant Law of mass action Reversible reaction
14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數 Vocabulary and Phrase 字與詞 The Equilibrium Constant Law of mass action Reversible reaction 平衡常數 質量作用定律 可逆反應

8 The Equilibrium Constant
14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數 Definition and Reading 定義與例句閱讀 The Equilibrium Constant 平衡常數 For a reversible reaction at equilibrium and a constant temperature, a certain ratio of reactant and product concentrations has a constant value, K (the equilibrium constant)

9 14.1 The Concept of Equilibrium and the Equilibrium Constant 平衡的觀念與平衡常數
For a reversible reaction at equilibrium and a constant temperature, a certain ratio of reactant and product concentrations has a constant value, K (the equilibrium constant) reversible reaction constant temperature ratio value 可逆反應 固定溫度 比例 數值 中譯: 當一個可逆反應在固定溫度下達到平衡時，反應物濃度和產物濃度的比值是一個固定的數值K, 稱為平衡常數。

10 14.2 Writing Equilibrium Constant Expression
Vocabulary and Phrase 字與詞 Homogeneous Equilibria Heterogeneous Equilibria Multiple Equilibria 均勻相平衡 非均勻相平衡 複合平衡, 多重平衡 Concentration Pressure Intensive Properties Extensive Properties 濃度 壓力 示強性質 如:密度、溫 度 示量性質 如:重量

11 14.2 Writing Equilibrium Constant Expression
Definition and Reading 定義與例句閱讀 Homogeneous Equilibria 均勻相平衡 The term homogeneous equilibria apply to reactions in which all reacting species are in the same phase.

12 14.2 Writing Equilibrium Constant Expression
The term homogeneous equilibria apply to reactions in which all reacting species are in the same phase. term apply to species 名詞, 術語 應用於 物種 中譯: 均勻相平衡一詞應用於反應中個反應物種均為同一相。

13 14.2 Writing Equilibrium Constant Expression
The subscript in Kc indicates that the concentrations of the reacting species are expressed in molarity or mole per liter. subscript indicate be expressed in 下標 指出, 表明 以…(單位)表示　 molarity mole per liter 體積莫耳濃度 每升幾莫耳　 中譯: Kc中的下標表明反應物的濃度以體積莫耳濃度或是每升幾莫耳來表示。

14 14.2 Writing Equilibrium Constant Expression
The concentrations of reactants and products in gaseous reaction can also be expressed in terms of their partial pressures. in terms of 依據　 Partial pressure 分壓　 中譯: 氣體反應中反應物及產物的濃度也可依據它們的分壓來表示。

15 14.2 Writing Equilibrium Constant Expression
The subscript in Kp tells us that the equilibrium concentrations are expressed in terms of pressure. 中譯: Kp中的下標告訴我們平衡時的濃度以壓力表示。

16 14.2 Writing Equilibrium Constant Expression
In general, Kc is not equal to Kp, because the partial pressures of reactants and products are not equal to their concentrations expressed in mole per liter. in general be equal to be not equal to 一般來說 等於 不等於　 中譯: 一般而言，Kc不等於Kp因為反應物和產物的分壓與以體積莫耳濃度所表示的濃度並不相等。

17 14.2 Writing Equilibrium Constant Expression
In general, Kc is not equal to Kp except in the special case in which Dn=0. except special case 除了 特例, 特殊情況　 中譯: 一般而言，Kc不等於Kp ，除非在Dn=0的特殊情況之下。

18 14.2 Writing Equilibrium Constant Expression
Definition and Reading 定義與例句閱讀 Heterogeneous Equilibria 非均勻相平衡 A heterogeneous equilibrium results from a reversible reaction involving reactants and products that are in different phases.

19 14.2 Writing Equilibrium Constant Expression
A heterogeneous equilibrium results from a reversible reaction involving reactants and products that are in different phases. result from involve (involving) 起因於, 源自… 包含, 牽涉 中譯: 所謂非均勻相平衡源自於包含有不同相態的反應物與產物的可逆反應。

20 14.2 Writing Equilibrium Constant Expression
The ‘concentration’ of a solid, like its density, is an intensive property and does not depend on how much of the substance is present. be (not) depend on be present (不)受影響 存在的, 在場的 中譯: 固體的所謂「濃度」，如同其密度，是一種示強性質，不受物質存在的多少所影響。

21 14.2 Writing Equilibrium Constant Expression
If a reaction can be expressed as the sum of two or more reactions, the equilibrium constant for the overall reaction is given by the product of the equilibrium constants of the individual reactions. be expressed as Individual product 以…表示 個別的 乘積　(相乘的結果) 中譯: 如果一個反應可以用兩個以上的反應的相加來表示，總反應的平衡常數是個別反應平衡常數的乘積(相乘) 。

22 14.2 Writing Equilibrium Constant Expression
Summary of Guidelines for Writing Equilibrium Constant Expressions 寫平衡常數公式的重點摘要 1.The concentrations of the reacting species in the condensed phase are expressed in mol/L; in the gaseous phase, the concentrations can be expressed in mol/L or in atm. Kc is related to Kp by a simple equation. condensed phase be expressed in (unit) be related to equation 凝相 (液相和固相的總稱) 以…(單位)表示 關聯 方程式, 等式 中譯: 凝像反應物的濃度以莫耳/升表示，氣相之濃度則以莫耳/升或是大氣壓力(atm) 表示， Kc 與 Kp 可以用簡單的等式相互關聯。

23 14.2 Writing Equilibrium Constant Expression
Summary of Guidelines for Writing Equilibrium Constant Expressions 寫平衡常數公式的重點摘要 2.The concentrations of pure solids, pure liquids (in heterogeneous equilibria), and solvents (in homogeneous equilibria) do not appear in the equilibrium constant expressions. pure appear in 純的 出現在…之中 中譯: (非均勻相的平衡裡)純固態或液態，(均勻相平衡裡的)溶劑的濃度是不出現在平衡常數的表達式中的。

24 14.2 Writing Equilibrium Constant Expression
Summary of Guidelines for Writing Equilibrium Constant Expressions 寫平衡常數公式的重點摘要 3. The equilibrium constant (Kc or Kp) is a dimensionless quantity. dimensionless quantity 無單位的 量, 數量 中譯: 平衡常數(Kc 或 Kp)是一個不具單位的數量。

25 14.2 Writing Equilibrium Constant Expression
Summary of Guidelines for Writing Equilibrium Constant Expressions 寫平衡常數公式的重點摘要 4.In quoting a value for the equilibrium constant, we must specify the balanced equation and the temperature. quote specify Balanced equation 引用, 摘錄 具體說明 已經平衡的(化學)方程式 中譯: 引用平衡常數數值時須具體說明其平衡式及溫度。

26 14.2 Writing Equilibrium Constant Expression
Summary of Guidelines for Writing Equilibrium Constant Expressions 寫平衡常數公式的重點摘要 5. If a reaction can be expressed as the sum of two or more reactions, the equilibrium constant for the overall reaction is given by the product of the equilibrium constants of the individual reactions. product 通常是結果或產物的意思, 但此處是乘積(相乘的結果) 中譯: 如果一個反應可以表達為兩個以上反應的總合，總反應的平衡常數可以用個別反應平衡常數的乘積表示。

27 14.3 The relationship Between Chemical Kinetics and Chemical Equilibrium 化學動力學與化學平衡的關係
In summary, we see that in terms of chemical kinetics, the equilibrium constant of a reaction can be expressed as a ratio of the rate constants of the forward and reverse reactions. in summary forward reaction reverse reaction 總之 正反應 逆反應 中譯: 總之, 我們從化學動力學來看, 反應的平衡常數可以用正反應與逆反應速率常數的比值表示。

28 14.4 What Does Equilibrium Constant Tell Us? 平衡常數能告訴我們甚麼?
We obtain the reaction quotient (Qc) by substituting the initial concentrations into the equilibrium constant expression. quotient substituting 商值 (比值) 取代 中譯: 將初始濃度帶入平衡常數的公式中我們可以得到反應商值。

29 14.4 What Does Equilibrium Constant Tell Us? 平衡常數能告訴我們甚麼?
Qc < Kc The ratio of initial concentrations of products to reactants is too small. To reach equilibrium, reactants must be converted to products. The system proceed from left to right (consuming reactants, forming products) to reach equilibrium. Qc < Kc 反應物初始濃度對反應物初始濃度的比值太小。 要達到平衡反應物必須轉換為產物。 系統從左至右進行(消耗反應物, 形成產物)以達到平衡。

30 14.4 What Does Equilibrium Constant Tell Us? 平衡常數能告訴我們甚麼?
Qc = Kc The initial concentrations are equilibrium concentrations. The system is at equilibrium. Qc = Kc 初始濃度已是平衡濃度。 系統在平衡狀態。

31 14.4 What Does Equilibrium Constant Tell Us? 平衡常數能告訴我們甚麼?
Qc > Kc The ratio of initial concentrations of products to reactants is too large. To reach equilibrium products must be converted to reactants. The system proceeds from right to left (consuming product, forming reactants) to reach equilibrium. Qc > Kc 反應物初始濃度對反應物初始濃度的比值太大。 要達到平衡產物必須轉換為反應物。 系統從右至左進行(消耗產物, 形成反應物)以達到平衡。

32 14.5 Factors That Affect Chemical Equilibrium 影響平衡常數的因素
Le Ch telier Principle states that if an external stress is applies to a system at equilibrium, the system adjusts in such a way that the stress is partially offset as the system reaches a new equilibrium position. external stress be applied to adjust 外在的 壓力,壓迫 施加於 調整 中譯: 勒沙特列原理說明如果一個外力施加於一個平衡系統, 系統會以部分抵銷該外力的方式進行調整以達到新的平衡。

33 14.5 Factors That Affect Chemical Equilibrium 影響平衡常數的因素
A temperature increase favors an endothermic reaction, and a temperature decrease favors an exothermic reaction. favor endothermic reaction exothermic reaction increase decrease 有利於, 偏向於 吸熱反應 放熱反應 增加 減少 中譯: 溫度增加有利於吸熱反應 , 溫度降低有利於放熱反應。

34 14.5 Factors That Affect Chemical Equilibrium 影響平衡常數的因素
Only a change in temperature changes the value of the equilibrium constant. value 數值 中譯: 只有溫度改變時平衡常數的數值才會改變。

35 14.5 Factors That Affect Chemical Equilibrium 影響平衡常數的因素
A catalyst can speed up the process, but it has no effect on the equilibrium constant and on the equilibrium concentrations of the reacting species. speed up effect 加速 影響 中譯: 催化劑能加速(反應)程序,隊反應平衡常數及反應物種平衡時的濃度並無影響。