缓冲溶液的有效范围是如何界定的？
How is the effective range of a buffer defined?
有效缓冲范围约为 pKa ± 1，对应 [A⁻]/[HA] 在 0.1 至 10 之间；超出此范围某一组分过少，难以中和外加酸碱。因此选缓冲剂须使其 pKa 接近目标 pH。
The effective buffer range is roughly pKa ± 1, where [A⁻]/[HA] lies between 0.1 and 10; beyond it one component is too scarce to neutralize added acid/base. Thus a buffer is chosen so its pKa is near the target pH.
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）
#缓冲范围 #pKa #比例
弱酸-强碱滴定曲线为何在半等当点出现 pH = pKa？
Why does pH = pKa at the half-equivalence point in a weak acid–strong base titration?
半等当点时一半弱酸被中和，[HA] = [A⁻]，代入亨德森方程得 pH = pKa。该点恰为缓冲容量最大处，曲线最平坦；由此可直接在半等当点读出弱酸的 pKa。
At half-equivalence, half the weak acid is neutralized, so [HA] = [A⁻], and Henderson-Hasselbalch gives pH = pKa. This is also where buffer capacity peaks and the curve is flattest, so pKa can be read off directly at the half-equivalence point.
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）
#滴定曲线 #半等当点 #pKa
血液中的主要缓冲系统是什么？
What is the main buffer system in blood?
主要是碳酸/碳酸氢盐系统（H₂CO₃/HCO₃⁻），由肺调节 CO₂、肾调节 HCO₃⁻ 共同维持 pH≈7.4。血红蛋白也缓冲运输中产生的 H⁺，三者协同保证生理 pH 稳定。
The main system is the carbonic acid/bicarbonate pair (H₂CO₃/HCO₃⁻), with the lungs regulating CO₂ and kidneys regulating HCO₃⁻ to keep pH≈7.4. Hemoglobin also buffers H⁺ from CO₂ transport, together stabilizing physiological pH.
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
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）
#血液缓冲 #碳酸氢盐 #pH
同离子效应如何影响弱酸与难溶盐？
How does the common-ion effect influence weak acids and sparingly soluble salts?
加入含相同离子的物质会使平衡向左移动：在弱酸中抑制解离（pH 升高），在难溶盐中降低溶解度。这是缓冲与沉淀分离的理论基础。
Adding a species with a common ion shifts equilibrium leftward: in a weak acid it suppresses dissociation (raising pH), and in a sparingly soluble salt it lowers solubility. This underlies buffers and precipitation separations.
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
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）
#同离子效应 #解离 #沉淀
配制指定 pH 缓冲液的一般步骤是什么？
What are the general steps to prepare a buffer at a target pH?
先选 pKa 最接近目标 pH 的弱酸/碱对，由亨德森方程算出 [A⁻]/[HA] 比，再用相近浓度的酸与共轭碱（或其盐）按计量混合，最后用 pH 计校准。常用方法包括半中和法与混盐法。
Pick a weak acid/base pair whose pKa is closest to the target pH, use Henderson-Hasselbalch to get the [A⁻]/[HA] ratio, mix the acid and its conjugate base (or salt) at matching concentration accordingly, then calibrate with a pH meter. Common routes are partial neutralization and salt-mixing.
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
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）
#缓冲配制 #pKa #校准
pKa 与缓冲能力有什么关系？
How is pKa related to buffering ability?
pKa 是酸解离一半时的 pH，也是该共轭对缓冲能力最强的点。缓冲只在 pH 接近 pKa 时有效，偏离越远，溶液对加酸或加碱越敏感。因此 pKa 是选择缓冲剂的判据。
pKa is the pH where the acid is half dissociated and where its conjugate pair buffers best. Buffering is effective only near pKa; the farther away, the more sensitive the solution is to added acid or base. Hence pKa guides buffer choice.
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
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）
#pKa #缓冲 #解离
什么是缓冲容量？受什么影响？
What is buffer capacity, and what affects it?
缓冲容量是使 pH 改变一个单位所需加入的强酸/强碱量。它随总浓度增大而增大，并在 [A⁻] ≈ [HA]（pH ≈ pKa）时最大，偏离此比例或浓度过低时缓冲能力急剧下降。
Buffer capacity is the amount of strong acid/base needed to change pH by one unit. It grows with total concentration and is maximal when [A⁻] ≈ [HA] (pH ≈ pKa);deviating from that ratio or low concentration sharply weakens buffering.
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
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）
#缓冲容量 #浓度 #pKa
为什么电池需要电解质？
Why do batteries need an electrolyte?
电解质在两极间传导离子，让电子只能走外电路形成电流。
The electrolyte carries ions between electrodes so electrons flow through the wire as current.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#电解质 #离子 #电池
为什么胃会分泌胃酸？
Why does the stomach make acid?
胃酸(盐酸)帮助分解食物并杀灭部分细菌。
Stomach acid (HCl) helps digest food and kills some bacteria.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#胃酸 #盐酸 #消化
为什么肥皂通常是碱性的？
Why is soap usually alkaline?
皂化反应用碱把油脂变成肥皂，成品略带碱性更易去油。
Saponification uses alkali to turn fat into soap, leaving it slightly alkaline to cut grease.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#肥皂 #皂化 #碱性
亨德森-哈塞尔巴尔赫方程用来做什么？
What is the Henderson-Hasselbalch equation used for?
pH = pKa + log([A⁻]/[HA]) 由弱酸及其共轭碱的浓度比直接估算缓冲溶液 pH。当 [A⁻] = [HA] 时 pH = pKa，是缓冲设计的核心关系。
pH = pKa + log([A⁻]/[HA]) estimates buffer pH from the conjugate base-to-acid ratio. When [A⁻] = [HA], pH = pKa—the central relation for buffer design.
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
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）
#缓冲 #pH #pKa
酚酞为什么在碱里变红、在酸里无色？
Why does phenolphthalein turn red in base but colorless in acid?
碱性下内酯开环成醌式离子而显粉红；酸性时回到无色的内酯形式。
In base the lactone opens to a quinonoid ion that is pink; in acid it returns to the colorless lactone form.
难度 进阶 · 适合 大众
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）
#酚酞 #指示剂 #变色
选择酸碱指示剂的依据是什么？
On what basis is an acid-base indicator chosen?
指示剂的变色范围（约 pKa ±1）应落在滴定突跃区间内。强酸强碱滴定突跃宽，多数指示剂可用；弱酸弱碱滴定突跃窄，需选变色范围匹配且靠近等当点 pH 的指示剂。
An indicator's color-change range (about pKa ±1) should fall within the titration's steep jump. Strong acid-base titrations have a wide jump so most indicators work; weak acid/base titrations need a narrow-jump indicator matching the equivalence-point pH.
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
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）
#指示剂 #pH #突跃
为什么酸雨会腐蚀建筑？
Why does acid rain corrode buildings?
酸雨里的硫酸、硝酸与石灰石和金属反应，慢慢侵蚀表面。
Acid rain's sulfuric/nitric acids react with limestone and metals, slowly eroding them.
难度 进阶 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸雨 #腐蚀 #石灰石
为什么白醋能除去水壶里的水垢？
Why does white vinegar remove limescale from kettles?
水垢主要是碳酸钙，醋里的醋酸能把它溶解成可溶的醋酸钙、水和二氧化碳。
Limescale is mostly calcium carbonate; acetic acid in vinegar dissolves it into soluble calcium acetate, water and CO2.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#醋酸 #水垢 #酸碱
缓冲溶液为什么能抵抗 pH 变化？
Why can a buffer resist pH changes?
缓冲溶液含弱酸及其共轭碱（或弱碱及其共轭酸）：加入酸时被共轭碱中和，加入碱时被弱酸中和，使 pH 仅小幅变动。它像“酸碱海绵”吸收外来的 H⁺ 或 OH⁻。
A buffer contains a weak acid and its conjugate base (or weak base and conjugate acid): added acid is consumed by the base, added base by the acid, so pH shifts only slightly. It acts like a sponge soaking up incoming H⁺ or OH⁻.
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
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）
#缓冲 #共轭 #中和
石蕊试纸怎么判断酸碱性？
How does litmus paper show acid or base?
石蕊在酸性变红、碱性变蓝，把试纸沾一点溶液就能粗略判断酸碱性。
Litmus turns red in acid and blue in base, giving a quick rough pH check.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#酸碱 #试纸 #指示剂
pH试纸为什么遇酸变红、遇碱变蓝？
Why does pH paper turn red in acid and blue in base?
试纸上浸了酸碱指示剂，这种染料在不同pH下分子结构改变、吸收的光不同，于是显出不同颜色。
The paper carries an indicator dye whose structure—and thus the light it absorbs—changes with pH, showing different colors.
难度 入门 · 适合 大众
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#pH试纸 #指示剂 #颜色
紫甘蓝汁为什么能当酸碱指示剂？
Why can red-cabbage juice be an acid-base indicator?
它含花青素，随 pH 改变结构而从红变紫再变绿，是天然的指示剂。
It contains anthocyanins that shift structure and color from red to purple to green with pH, acting as a natural indicator.
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
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）
#指示剂 #花青素 #紫甘蓝
为什么醋能除异味？
Why does vinegar remove odors?
醋的酸能中和碱性异味分子，也能溶解部分污垢。
Vinegar's acid neutralizes basic odor molecules and dissolves some grime.
难度 入门 · 适合 小学高段(9-12)
CC BY 4.0 · 已核验 · Verified 2026-08-23
来源 · Source
Brown, LeMay 等,《Chemistry: The Central Science》第14版,Pearson,2017
T. L. Brown et al., Chemistry: The Central Science, 14th ed., Pearson, 2017
#醋 #中和 #异味