平衡常数与自由能有什么关系？
How are the equilibrium constant and free energy related?
在恒温下，标准反应自由能变与平衡常数 K 满足 ΔrG° = –RT ln K。K 很大时 ΔG° 为负，平衡强烈偏向产物；K 很小则偏向反应物。这一关系把热力学（可能性）与平衡位置直接联系起来。
At constant temperature, the standard reaction free energy and equilibrium constant obey ΔrG° = –RT ln K. A large K means negative ΔG° and products strongly favored; a small K favors reactants. This links thermodynamics (feasibility) directly to equilibrium position.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
傅献彩 等,《物理化学》第5版,高等教育出版社,2005
Fu Xiancai et al., Physical Chemistry, 5th ed., Higher Education Press, 2005
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9787040167696（按标识回读: 物理化学(第五版)上册）
#平衡常数 #自由能 #范特霍夫
玻恩-哈伯循环如何求离子化合物的晶格能？
How does a Born-Haber cycle determine lattice energy of an ionic compound?
将固体盐的形成分解为升华、电离、解离、电子亲和及晶格形成等步骤，利用 Hess 定律：由元素生成化合物的标准焓变等于各步焓变之和，从而解出无法直接测定的晶格能。
The formation of a solid salt is broken into sublimation, ionization, dissociation, electron affinity, and lattice formation steps; Hess's law states the net formation enthalpy equals their sum, letting you solve for the otherwise unmeasurable lattice energy.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#玻恩-哈伯 #晶格能 #离子化合物
什么是标准生成焓？
What is standard enthalpy of formation?
标准生成焓（ΔfH°）是在标准状态（通常 100 kPa、指定温度）下，由最稳定单质生成 1 摩尔化合物时的焓变。稳定单质的生成焓定义为零。利用各物质的标准生成焓可计算反应的焓变：ΔrH° = ΣΔfH°(产物) – ΣΔfH°(反应物)。
Standard enthalpy of formation (ΔfH°) is the enthalpy change when one mole of a compound forms from its most stable elements in their standard states (usually 100 kPa at a specified temperature). The most stable elements are assigned zero. Reaction enthalpy is ΔrH° = ΣΔfH°(products) – ΣΔfH°(reactants).
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
傅献彩 等,《物理化学》第5版,高等教育出版社,2005
Fu Xiancai et al., Physical Chemistry, 5th ed., Higher Education Press, 2005
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9787040167696（按标识回读: 物理化学(第五版)上册）
#标准生成焓 #标准状态 #焓变
热力学第二定律的常见表述是什么？
What is a common statement of the second law of thermodynamics?
第二定律有多种等价表述，克劳修斯表述为热量不能自发从低温物体传到高温物体。它宣告了过程的不可逆性，并引出熵增原理：孤立体系的熵总是趋向最大。这解释了为什么混合、扩散等过程不可逆。
The second law has several equivalent forms; Clausius stated that heat cannot spontaneously flow from a colder to a hotter body. It declares the irreversibility of processes and leads to the entropy-increase principle: an isolated system's entropy tends toward a maximum. This explains why mixing and diffusion are irreversible.
难度 专业 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
傅献彩 等,《物理化学》第5版,高等教育出版社,2005
Fu Xiancai et al., Physical Chemistry, 5th ed., Higher Education Press, 2005
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9787040167696（按标识回读: 物理化学(第五版)上册）
#热力学第二定律 #克劳修斯 #熵增
平均键焓与标准生成焓有何区别？
How do average bond enthalpies differ from standard enthalpies of formation?
平均键焓是某类化学键在不同分子中键能的平均值，与分子环境无关；标准生成焓是针对特定化合物由其元素生成的精确值。用键焓估算 ΔH 仅是近似，因实际键能随结构变化。
Average bond enthalpy is a mean bond energy for a bond type across molecules, independent of context; standard enthalpy of formation is an exact value for a specific compound from its elements. Bond-enthalpy estimates of ΔH are approximate because real bond energies vary with structure.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#键焓 #生成焓 #估算
盖斯定律是什么？有什么用处？
What is Hess's law and what is it useful for?
盖斯定律指出，化学反应的热效应只与始态和终态有关，与反应途径无关。因此可以把多个已知反应热的方程式相加，间接求得难以直接测量的反应焓变。它在热化学计算和工业过程设计中非常实用。
Hess's law states that the heat of a reaction depends only on initial and final states, not the pathway. Thus one can add equations with known reaction heats to find an enthalpy change that is hard to measure directly. It is practical in thermochemical calculations and industrial process design.
难度 进阶 · 适合 高中(15-18)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
傅献彩 等,《物理化学》第5版,高等教育出版社,2005
Fu Xiancai et al., Physical Chemistry, 5th ed., Higher Education Press, 2005
独立核验依据 · Independent verification: 核验依据 2 DOUBAN ISBN 标识 9787040167696（按标识回读: 物理化学(第五版)上册）
#盖斯定律 #反应热 #热化学
热力学中的“标准状态”指什么？
What does 'standard state' mean in thermodynamics?
标准状态指物质在 1 bar 压力下的最稳定形态（溶液为 1 mol/L 的理想状态），温度可另指定（常取 298.15 K）。标准焓、熵、自由能都相对于此参照态定义。
The standard state is a substance's most stable form at 1 bar pressure (1 mol/L ideal solution for solutes), with temperature specified separately (often 298.15 K). Standard enthalpy, entropy, and free energy are all defined relative to this reference.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#标准状态 #参考态 #热力学
盖斯定律（Hess's law）的原理是什么？
What is the principle behind Hess's law?
因为焓是状态函数，反应总焓变只取决于始态和终态，与路径无关。因此可把已知反应相加减，间接求出难以直接测量的反应焓。
Because enthalpy is a state function, the total enthalpy change depends only on initial and final states, not the path. Known reactions can thus be combined to find enthalpies that are hard to measure directly.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#盖斯定律 #焓 #状态函数
公式 q = mcΔT 中各量代表什么？
What do the terms in q = mcΔT represent?
q 是吸收或放出的热量，m 是物质质量，c 是比热容（单位质量升高 1℃ 所需热量），ΔT 是温度变化。量热法用它测定反应热。
q is heat absorbed or released, m is mass, c is specific heat capacity (heat per unit mass per 1°C rise), and ΔT is the temperature change. Calorimetry uses this to measure reaction heats.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-08-23 · 2 条独立证据
来源 · Source
Atkins, de Paula, Keeler,《Atkins' Physical Chemistry》第11版,Oxford University Press,2018
P. Atkins, J. de Paula and J. Keeler, Atkins' Physical Chemistry, 11th ed., Oxford University Press, 2018
独立核验依据 · Independent verification: 核验依据 2 ISBN 978-0-19-884781-6 (11th ed., Oxford University Pres
#量热 #比热容 #热量