为什么泡打粉遇水又遇热都会产气？
Why does baking powder release gas both with water and with heat?
泡打粉是碳酸氢钠加两种酸性盐（如焦磷酸二氢钠、磷酸铝钠等）的混合物：遇水时一部分酸先反应放出二氧化碳，加热时另一部分酸再反应继续产气。这种双重作用让面团在搅拌和烘烤两阶段都膨松。
Baking powder mixes sodium bicarbonate with two kinds of acid salts (e.g., sodium acid pyrophosphate, sodium aluminum phosphate): one reacts with water to release CO2 during mixing, and another reacts on heating to release more during baking. This double-acting leavening lifts the dough in both stages.
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）
#泡打粉 #双重作用 #膨松
什么是强酸和弱酸？
What are strong and weak acids?
强酸在水中几乎完全电离，如盐酸、硫酸和硝酸。弱酸只部分电离，如醋酸和碳酸，因此相同浓度下酸性较弱。
Strong acids ionize almost completely in water, such as hydrochloric, sulfuric, and nitric acids. Weak acids only partially ionize, such as acetic and carbonic acids, so they are less acidic at the same concentration.
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）
#强酸 #弱酸 #电离
为什么雨水有时候是弱酸性的（酸雨）？
Why is rain sometimes weakly acidic (acid rain)?
正常雨水因溶有二氧化碳本就微酸（pH约5.6）。工业排放的二氧化硫、氮氧化物在空气中氧化成硫酸、硝酸，随雨落下使pH更低，形成酸雨，会腐蚀建筑和伤害植物。控制排放是治理关键。
Even normal rain is slightly acidic (pH about 5.6) from dissolved carbon dioxide. Industrial sulfur dioxide and nitrogen oxides oxidize in air to sulfuric and nitric acids that fall with rain, lowering pH into acid rain, which corrodes buildings and harms plants. Cutting emissions is the key fix.
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）
#酸雨 #二氧化硫 #环境
为什么叫碱性电池，它和普通电池有何不同？
Why is it called an alkaline battery and how does it differ?
碱性电池以氢氧化钾等强碱为电解液，而传统锌锰干电池用氯化铵等中性或弱酸电解质。碱性环境让锌负极反应更高效、内阻更低、容量和放电更优。但它不能充电，且漏液有腐蚀性碱。
An alkaline battery uses a strong base like potassium hydroxide as electrolyte, whereas traditional zinc-carbon cells use neutral or weakly acidic ammonium chloride. The alkaline medium lets the zinc anode react more efficiently with lower internal resistance, giving better capacity and discharge. It is not rechargeable, and leaks are corrosive alkali.
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）
#碱性电池 #电解液 #电化学
路易斯酸碱理论与布朗斯特酸碱理论有什么不同？为什么说 BF₃ 是酸却不含氢？
How does Lewis acid–base theory differ from Brønsted–Lowry theory, and why is BF₃ called an acid despite having no hydrogen?
布朗斯特酸碱以"质子（H⁺）的给受"来定义，而路易斯酸碱以"电子对的给受"来定义：路易斯酸是电子对受体。BF₃ 中的硼有空的 p 轨道可接受电子对，所以是路易斯酸，但它本身既不能给出也不含可被给出的质子。
Brønsted–Lowry theory defines acids and bases by proton donation and acceptance, whereas Lewis theory uses electron-pair donation and acceptance—a Lewis acid is an electron-pair acceptor. BF₃ has an empty orbital on boron that accepts an electron pair, making it a Lewis acid even though it contains no proton to donate.
难度 专业 · 适合 高中(15-18)
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
#路易斯酸碱 #布朗斯特酸碱 #电子对受体 #BF3
什么是中和反应？
What is a neutralization reaction?
中和反应是酸和碱反应生成盐和水的反应，本质是氢离子与氢氧根结合成水。中和反应通常放热，常用于调节土壤酸度和处理胃酸。
A neutralization reaction is the reaction of an acid and a base to form a salt and water, essentially hydrogen ions combining with hydroxide ions to make water. It is usually exothermic and is used to adjust soil acidity and treat stomach acid.
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）
#中和反应 #盐 #水
为什么氨水（或含氨玻璃水）能去油又擦亮玻璃？
Why does ammonia (or ammonia glass cleaner) cut grease and shine glass?
氨是碱性，能皂化油脂并帮助乳化污垢，所以去油力强。它挥发快、残留少，擦玻璃后不易留痕、显得透亮。但氨有刺激性气味，使用时要通风、避免和漂白剂混用。
Ammonia is alkaline, so it saponifies fats and helps emulsify grime, giving strong degreasing. It evaporates fast with little residue, so glass looks clear without streaks. But ammonia is irritant—ventilate and never mix it with bleach.
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）
#氨水 #碱性 #去油
为什么柠檬是酸的？
Why is a lemon sour?
柠檬含有柠檬酸等有机酸，这些酸在水中释放出氢离子，刺激舌头产生酸味。柠檬汁的pH大约只有2到3，属于强酸性。
Lemons contain organic acids such as citric acid, which release hydrogen ions in water and stimulate the tongue to produce a sour taste. Lemon juice has a pH of about 2 to 3, making it strongly acidic.
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）
#柠檬酸 #酸味 #pH
为什么吃太酸或太甜会反酸、烧心？
Why do very acidic or very sweet foods cause heartburn?
过酸食物直接刺激、过甜和高脂食物会松弛食管下括约肌，使胃酸反流到食管，产生烧心感。胃内酸度高时症状更明显。少食多餐、饭后不立刻平躺有助于缓解。
Acidic foods irritate directly, while sweet or fatty ones relax the lower esophageal sphincter, letting stomach acid reflux into the esophagus and burn. Symptoms worsen when gastric acidity is high. Smaller meals and not lying down right after eating help.
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）
#反酸 #食管 #胃酸
什么是酸雨？
What is acid rain?
酸雨是pH低于约5.6的降水，主要由二氧化硫和氮氧化物在大气中转化为硫酸和硝酸造成。它会酸化土壤和湖泊，损害森林和建筑物。
Acid rain is precipitation with a pH below about 5.6, mainly caused by sulfur dioxide and nitrogen oxides turning into sulfuric and nitric acids in the atmosphere. It acidifies soil and lakes and damages forests and buildings.
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）
#酸雨 #二氧化硫 #污染
胃酸是什么，它有什么作用？
What is stomach acid and what does it do?
胃酸主要成分是盐酸，pH约为1.5到3.5，能帮助消化蛋白质并杀灭进入胃里的细菌。胃酸分泌过多会引起烧心或胃溃疡。
Stomach acid is mainly hydrochloric acid with a pH of about 1.5 to 3.5, helping digest proteins and kill bacteria entering the stomach. Too much acid can cause heartburn or ulcers.
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）
#胃酸 #盐酸 #消化
为什么柠檬酸也能除水垢，和醋比如何？
Why does citric acid also remove scale, and how does it compare with vinegar?
柠檬酸是有机酸，能像醋酸一样与碳酸钙等水垢反应生成可溶盐，但酸性更强、用量更少、无味。它常做成除垢剂用于咖啡机、电水壶。除垢后同样要冲洗干净。
Citric acid is an organic acid that, like acetic acid, reacts with scale such as calcium carbonate into soluble salts, but it is stronger, needs less, and is odorless. It is often sold as descaler for coffee makers and kettles. Rinse well afterward, just the same.
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）
#柠檬酸 #除垢 #有机酸
缓冲溶液为什么能抵抗 pH 变化？它的缓冲能力为什么是有限的？
Why can a buffer solution resist pH change, and why is its capacity limited?
缓冲对（如醋酸/醋酸根）中，加入少量酸时被其共轭碱中和，加入少量碱时被弱酸中和，使 pH 基本不变。但缓冲组分的总量是有限的，一旦被外加酸碱大量消耗或比例失衡（通常超出 1:10–10:1 范围），缓冲能力就会急剧下降。
In a buffer pair (e.g., acetic acid/acetate), added acid is consumed by the conjugate base and added base by the weak acid, keeping pH nearly constant. The total amount of buffer components is finite, however, so once they are largely consumed or the ratio leaves the ~1:10–10:1 range, buffering collapses.
难度 进阶 · 适合 初中(12-15)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
Brown, LeMay & Bursten《化学：中心科学》（第14版），第17章
Brown, LeMay & Bursten, "Chemistry: The Central Science" (14th ed.), Ch.17
独立核验依据 · Independent verification: 核验依据 1 ARCHIVE 标识 studentlectureno00theo：Chemistry, the central
#缓冲溶液 #共轭酸碱 #缓冲容量 #pH
为什么小苏打能缓解胃酸过多？
Why does baking soda relieve excess stomach acid?
小苏打（碳酸氢钠）是弱碱，能与胃酸（盐酸）发生中和反应，生成氯化钠、水和二氧化碳，从而暂时降低胃内酸度。产生的气体可能让人打嗝。它只能临时救急，长期用会反跳性产酸，且钠含量高。
Baking soda (sodium bicarbonate) is a weak base that neutralizes stomach acid (HCl) into sodium chloride, water, and carbon dioxide, temporarily lowering acidity. The gas may make you burp. It is only a short-term fix; long use causes rebound acid and adds sodium.
难度 入门 · 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）
#小苏打 #中和 #胃酸
pH 是什么？它如何表示酸碱强弱？
What is pH and how does it express acidity or basicity?
pH 是溶液中氢离子活度负对数的度量：pH = –log a(H⁺)。pH<7 为酸性、=7 为中性、>7 为碱性（25℃）。它用对数压缩了巨大的浓度跨度，使强酸弱酸的差别一目了然。pH 计和试纸是常用测量工具。
pH is the negative logarithm of hydrogen-ion activity: pH = –log a(H⁺). Below 7 is acidic, 7 neutral, above 7 basic (at 25°C). The logarithm compresses a huge concentration range so strong and weak acids are easy to compare. pH meters and papers are common tools.
难度 入门 · 适合 幼儿(3-6)
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 #氢离子 #酸碱度
为什么纯水的中性点在 pH=7，而且这个"7"只有在常温（约25°C）下才算中性？
Why is pH = 7 considered neutral only at room temperature, not under all conditions?
中性指 [H⁺] = [OH⁻]，而水的离子积 Kw 随温度升高而增大。25°C 时 Kw≈10⁻¹⁴，中性 pH=7；当升温到 100°C 时 Kw≈10⁻¹²，中性 pH 降到约 6，此时 pH=7 反而偏碱。
Neutrality means [H⁺] = [OH⁻], but water's ion product Kw grows with temperature. At 25°C, Kw ≈ 10⁻¹⁴ so neutral pH is 7; at 100°C, Kw ≈ 10⁻¹² and neutral pH falls to about 6, so pH 7 would actually be basic.
难度 入门 · 适合 小学低段(6-8)
CC BY 4.0 · 已核验 · Verified 2026-11-03
来源 · Source
IUPAC 金色手册（Gold Book）"pH"词条；Atkins & de Paula《物理化学》第9章
IUPAC Gold Book — definition of pH; Atkins & de Paula, "Physical Chemistry," Ch.9
独立核验依据 · Independent verification: 核验依据 1 OPENLIBRARY 标识 /works/OL1907523W：Physical chemistry（首版 1
#水的离子积 #中性 #pH #温度
为什么pH试纸遇酸碱会变色？
Why does pH paper change color in acid or base?
pH试纸浸有混合酸碱指示剂，这些染料分子在不同氢离子浓度下结构改变，吸收的光颜色随之变化。对照标准色卡就能读出大致pH值。它是实验室和生活中快速测酸碱的方便工具。
pH paper is soaked with a mix of acid-base indicators whose dye molecules change structure at different hydrogen-ion concentrations, shifting the color of absorbed light. Comparing with a standard chart gives an approximate pH. It is a handy quick test in labs and daily life.
难度 入门 · 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）
#pH试纸 #指示剂 #变色
为什么我们的胃酸是盐酸？
Why is our stomach acid hydrochloric acid?
胃壁细胞分泌盐酸，使胃内pH降到1.5至3.5，既能激活消化酶分解蛋白质，又能杀灭随食物进入的细菌。酸性环境还能帮助铁、钙等矿物质溶解吸收。但分泌过多会反酸、伤胃黏膜。
Stomach lining cells secrete hydrochloric acid, dropping gastric pH to 1.5–3.5 so digestive enzymes can break down protein and kill bacteria entering with food. The acid also helps dissolve and absorb minerals like iron and calcium. Too much, though, causes reflux and harms the mucosa.
难度 入门 · 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）
#胃酸 #盐酸 #消化
为什么醋是酸性的？
Why is vinegar acidic?
醋是粮食或水果发酵产生的，主要酸性成分是乙酸（约3%至5%）。乙酸电离出氢离子，所以pH偏低、尝起来酸。不同醋还含乳酸、苹果酸等，带来各自风味。
Vinegar comes from fermenting grains or fruit, and its main acid is acetic acid at about 3%–5%. Acetic acid releases hydrogen ions, so the pH is low and it tastes sour. Other acids like lactic or malic add distinctive flavors.
难度 入门 · 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）
#醋 #乙酸 #酸性
酸和碱混合会发生什么？
What happens when an acid and a base are mixed?
酸和碱混合会发生中和反应，生成盐和水，溶液的酸碱性会减弱。比如小苏打（碱）可以用来减轻胃酸过多带来的不适。
When an acid and a base are mixed they undergo neutralization, forming a salt and water, and the solution becomes less acidic or basic. For example, baking soda, a base, can relieve discomfort from excess stomach acid.
难度 入门 · 适合 小学高段(9-12)
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）
#中和 #盐 #水
酸和碱有什么不同？
What is the difference between an acid and a base?
酸是尝起来发酸、能使蓝色石蕊变红的物质，如醋里的醋酸。碱多有滑腻感、能使红色石蕊变蓝，如肥皂里的成分。
An acid tastes sour and turns blue litmus red, such as acetic acid in vinegar. A base feels slippery and turns red litmus blue, such as the ingredients in soap.
难度 入门 · 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）
#酸 #碱 #石蕊
用石蕊试纸怎么分辨酸和碱？
How do you use litmus paper to tell acids from bases?
把试纸浸入溶液，若变红说明是酸性，若变蓝说明是碱性，颜色不变则接近中性。石蕊是一种常用的酸碱指示剂。
Dip the paper into the solution: red means acidic, blue means basic, and no change means nearly neutral. Litmus is a common acid-base indicator.
难度 入门 · 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）
#石蕊 #指示剂 #酸碱