| 核心内容 | 补充内容 |
|---|---|
| 1 为测量时间、温度、质量和体积命名适当的仪器，包括：(a) 秒表 (b) 温度计 (c) 天平 (d) 滴定管 (e) 移液管 (f) 量筒 (g) 气体注射器 | |
| 2 建议实验方法和仪器的优缺点 | |
| 3 描述以下概念：(a) 溶剂作为能溶解溶质的物质 (b) 溶质作为被溶剂溶解的物质 (c) 溶液作为一种或多种溶质溶解在溶剂中形成的混合物 (d) 饱和溶液作为在特定温度下含有该溶质最大浓度的溶液 (e) 残留物作为蒸发、蒸馏、过滤或任何类似过程后剩余的物质 (f) 滤液作为通过过滤器后的液体或溶液 |
实验技术与化学分析
IGCSE 化学 · 知识点 12
13:26
实验技术
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英语旁白 · 英中内嵌字幕
12.1
实验设计
教学大纲
来源：Cambridge International 教学大纲
English
Apparatus
You should know which piece of apparatus to use for each measurement:
| Measurement | Apparatus |
|---|---|
| time | stop-watch 秒表 |
| temperature | thermometer 温度计 |
| mass | balance 天平 |
| volume (accurate) | burette 滴定管 or volumetric pipette 移液管 |
| volume (rough) | measuring cylinder 量筒 |
| volume of a gas | gas syringe 注射器 |
Key words
These words are used throughout practical chemistry:
- A solvent 溶剂 is a substance that dissolves a solute.
- A solute 溶质 is the substance that dissolves in the solvent.
- A solution 溶液 is a mixture of one or more solutes dissolved in a solvent.
- A saturated solution 饱和溶液 holds the maximum amount of solute that will dissolve at a given temperature.
- A residue 残渣 is the substance left behind after evaporation, distillation or filtration.
- A filtrate 滤液 is the liquid that has passed through a filter.
探索
实验设计路径
遵循公平测试从问题到可靠结论的流程。
词汇
训练
| English | 中文 | 拼音 |
|---|---|---|
| stop-watch/stɒp wɒtʃ/ | 秒表 | miǎo biǎo |
| thermometer/θɜːˈmɒmɪtə/ | 温度计 | wēn dù jì |
| balance/ˈbæləns/ | 天平 | tiān píng |
| burette/bjʊəˈret/ | 滴定管 | dī dìng guǎn |
| volumetric pipette/ˌvɒljuːˈmetrɪk pɪˈpet/ | 移液管 | yí yè guǎn |
| measuring cylinder/ˈmeʒərɪŋ ˈsɪlɪndə/ | 量筒 | liáng tǒng |
| gas syringe/ɡæs sɪˈrɪndʒ/ | 注射器 | zhù shè qì |
| solvent/ˈsɒlvənt/ | 溶剂 | róng jì |
| solute/ˈsɒljuːt/ | 溶质 | róng zhì |
| solution/səˈluːʃn/ | 溶液 | róng yè |
| saturated solution/ˈsætʃəreɪtɪd səˈluːʃn/ | 饱和溶液 | bǎo hé róng yè |
| residue/ˈresɪdjuː/ | 残渣 | cán zhā |
| filtrate/ˈfɪltreɪt/ | 滤液 | lǜ yè |
12.2
酸碱滴定
教学大纲
| 核心 | 补充 |
|---|---|
| 1 描述酸碱滴定过程，包括使用：(a) 滴定管 (b) 移液管 (c) 合适的指示剂 | |
| 2 描述如何利用指示剂确定滴定的终点 |
来源：Cambridge International 教学大纲
English
A titration 滴定 measures the volume of one solution needed to react with a measured amount of another.
- Use a volumetric pipette to measure a fixed volume of one solution into a flask.
- Add a few drops of a suitable indicator 指示剂.
- Add the other solution from a burette, slowly, until the colour just changes.
The end-point 终点 is the observed indicator colour change. Choose a suitable indicator so this occurs close to the equivalence point, where the reactants have combined in the required ratio. The two points need not be exactly identical. Read the burette to find the volume added.
探索
酸碱滴定
pH 在等当点跃升
随着碱被加入追踪 pH——它在等当点跃过中性。
词汇
训练
| English | 中文 | 拼音 |
|---|---|---|
| titration/taɪˈtreɪʃn/ | 滴定 | dī dìng |
| indicator/ˈɪndɪkeɪtə/ | 指示剂 | zhǐ shì jì |
| end-point/end pɔɪnt/ | 终点 | zhōng diǎn |
12.3
色谱法
教学大纲
| 核心 | 补充 |
|---|---|
| 1 描述如何使用合适的溶剂，通过纸色谱法分离可溶性有色物质的混合物 | 3 描述如何使用合适的溶剂和显色剂，通过纸色谱法分离可溶性无色物质的混合物（无需了解具体显色剂的种类） |
| 2 解读简单的色谱图以识别：(a) 通过与已知物质比较来鉴定未知物质；(b) 纯净物和混合物 | 4 陈述并运用 $R_{\text{f}}$ 值的方程： $$R_{\text{f}} = \frac{\text{物质移动的距离}}{\text{溶剂移动的距离}}$$ |
来源：Cambridge International 教学大纲
English
Paper chromatography 纸色谱法 separates a mixture of soluble substances. You put a spot of the mixture near the bottom of the paper, then stand the paper in a solvent. As the solvent rises up the paper, the substances move different distances, so they separate.
- For coloured substances you can see the spots directly.
- For colourless substances you must spray a locating agent 显色剂 to make the spots show up.
The finished paper is a chromatogram 色谱图. You can use it to:
- identify an unknown substance by comparing it with known substances;
- tell if a substance is pure (a pure substance gives only one spot).
You can also calculate the $R_{\text{f}}$ value of a spot:
$$R_{\text{f}} = \frac{\text{distance moved by the substance}}{\text{distance moved by the solvent}}$$
Worked example. On a chromatogram the solvent front has risen 8.0 cm from the baseline, and a spot has moved 6.0 cm. Find its $R_{\text{f}}$ value.
$$R_{\text{f}} = \frac{6.0}{8.0} = 0.75$$
Both distances are measured from the baseline (the pencil line), and the spot's distance is taken to the centre of the spot. An $R_{\text{f}}$ has no unit, and it is always less than 1, because a spot can never travel further than the solvent carrying it - an answer above 1 means the two distances have been divided the wrong way round.
探索
色谱法路径
观察混合溶剂前沿移动时混合物的分离情况。
词汇
训练
| English | 中文 | 拼音 |
|---|---|---|
| paper chromatography/ˈpeɪpə krəʊməˈtɒɡrəfi/ | 纸色谱法 | zhǐ sè pǔ fǎ |
| locating agent/ləʊˈkeɪtɪŋ ˈeɪdʒənt/ | 显色剂 | xiǎn sè jì |
| chromatogram/krəʊˈmætəɡræm/ | 色谱图 | sè pǔ tú |
12.4
分离与提纯
教学大纲
| 核心内容 | 补充内容 |
|---|---|
| 1 描述并解释使用以下方法进行分离和提纯的原理：(a) 合适的溶剂 (b) 过滤 (c) 结晶 (d) 简单蒸馏 (e) 分馏 | |
| 2 根据所给物质的信息，建议合适的分离和提纯技术 | |
| 3 利用熔点和沸点数据鉴定物质并评估其纯度 |
来源：Cambridge International 教学大纲
English
You choose a method based on the mixture:
| Method | Used to separate |
|---|---|
| dissolving in a suitable solvent, then filtration 过滤 | an insoluble solid from a liquid |
| crystallisation 结晶 | a soluble solid from its solution |
| simple distillation 蒸馏 | a solvent (the liquid) from a solution |
| fractional distillation 分馏 | two or more liquids with different boiling points |
You can check the purity of a substance using its melting point 熔点 and boiling point 沸点: a pure substance melts and boils at sharp, fixed temperatures, while impurities lower the melting point and raise the boiling point.
探索
分离方法实验室
选择与混合物相匹配的方法。
词汇
训练
| English | 中文 | 拼音 |
|---|---|---|
| filtration/fɪlˈtreɪʃn/ | 过滤 | guò lǜ |
| crystallisation/ˌkrɪstəlaɪˈzeɪʃn/ | 结晶 | jié jīng |
| simple distillation/ˈsɪmpl dɪstɪˈleɪʃn/ | 蒸馏 | zhēng liú |
| fractional distillation/ˈfrækʃənl dɪstɪˈleɪʃn/ | 分馏 | fēn liú |
| melting point/ˈmeltɪŋ pɔɪnt/ | 熔点 | róng diǎn |
| boiling point/ˈbɔɪlɪŋ pɔɪnt/ | 沸点 | fèi diǎn |
12.5
离子与气体的鉴定
教学大纲
| 核心内容 | 补充内容 |
|---|---|
| 1 描述用于鉴定以下阴离子的测试方法：(a) 碳酸根离子 $\text{CO}_3^{2-}$，通过与稀酸反应并随后检验二氧化碳气体；(b) 氯离子 $\text{Cl}^-$、溴离子 $\text{Br}^-$ 和碘离子 $\text{I}^-$，通过用稀硝酸酸化后加入硝酸银溶液；(c) 硝酸根离子 $\text{NO}_3^-$，使用铝箔与氢氧化钠溶液进行还原反应，随后检验氨气；(d) 硫酸根离子 $\text{SO}_4^{2-}$，通过用稀硝酸酸化后加入硝酸钡溶液；(e) 亚硫酸根离子 $\text{SO}_3^{2-}$，通过与酸化的酸性高锰酸钾(VII)溶液反应 | |
| 2 描述使用氢氧化钠溶液和氨水来鉴定以下水合阳离子的测试方法：(a) 铝离子 $Al^{3+}$ (b) 铵根离子 $NH_4^+$ (c) 钙离子 $Ca^{2+}$ (d) 铬(III)离子 $Cr^{3+}$ (e) 铜(II)离子 $Cu^{2+}$ (f) 铁(II)离子 $Fe^{2+}$ (g) 铁(III)离子 $Fe^{3+}$ (h) 锌离子 $Zn^{2+}$ | |
| 3 描述用于鉴定以下气体的测试方法：(a) 氨气 $NH_3$，使用湿润的红色石蕊试纸；(b) 二氧化碳 $CO_2$，使用澄清石灰水；(c) 氯气 $Cl_2$，使用湿润的石蕊试纸；(d) 氢气 $H_2$，使用燃着的木条；(e) 氧气 $O_2$，使用带火星的木条；(f) 二氧化硫 $SO_2$，使用酸化的酸性高锰酸钾(VII)溶液 | |
| 4 描述利用焰色反应来鉴定以下阳离子的方法：(a) 锂离子 $Li^+$ (b) 钠离子 $Na^+$ (c) 钾离子 $K^+$ (d) 钙离子 $Ca^{2+}$ (e) 钡离子 $Ba^{2+}$ (f) 铜(II)离子 $Cu^{2+}$ |
来源：Cambridge International 教学大纲
English
Tests for anions
An anion 阴离子 is a negative ion.
| Anion | Test | Result |
|---|---|---|
| carbonate 碳酸根离子 ($\text{CO}_3^{2-}$) | add dilute acid | fizzes; the gas turns limewater milky (carbon dioxide 二氧化碳) |
| chloride 氯离子 ($\text{Cl}^-$) | add dilute nitric acid 硝酸, then silver nitrate 硝酸银 | white precipitate |
| bromide 溴离子 ($\text{Br}^-$) | add dilute nitric acid, then silver nitrate | cream precipitate |
| iodide 碘离子 ($\text{I}^-$) | add dilute nitric acid, then silver nitrate | yellow precipitate |
| nitrate 硝酸根离子 ($\text{NO}_3^-$) | add aluminium 铝 foil and sodium hydroxide 氢氧化钠, warm | ammonia 氨气 gas given off |
| sulfate 硫酸根离子 ($\text{SO}_4^{2-}$) | add dilute nitric acid, then barium nitrate 硝酸钡 | white precipitate |
| sulfite 亚硫酸根离子 ($\text{SO}_3^{2-}$) | add acidified potassium manganate(VII) 高锰酸钾 | purple colour fades |
Tests for cations
A cation 阳离子 is a positive ion. Add aqueous sodium hydroxide, or aqueous ammonia, and look at the precipitate 沉淀 formed.
| Cation | With sodium hydroxide | With aqueous ammonia |
|---|---|---|
| aluminium ($\text{Al}^{3+}$) | white, dissolves in excess | white, stays |
| ammonium 铵 ($\text{NH}_4^+$) | ammonia gas when warmed | — |
| calcium 钙 ($\text{Ca}^{2+}$) | white, stays | no precipitate |
| chromium(III) 铬 ($\text{Cr}^{3+}$) | green, dissolves in excess | green, stays |
| copper(II) 铜 ($\text{Cu}^{2+}$) | light blue, stays | light blue, dissolves to deep blue |
| iron(II) 铁 ($\text{Fe}^{2+}$) | green, stays | green, stays |
| iron(III) ($\text{Fe}^{3+}$) | red-brown, stays | red-brown, stays |
| zinc 锌 ($\text{Zn}^{2+}$) | white, dissolves in excess | white, dissolves in excess |
Tests for gases
| Gas | Test | Result |
|---|---|---|
| ammonia ($\text{NH}_3$) | damp red litmus 石蕊 paper | turns blue |
| carbon dioxide ($\text{CO}_2$) | bubble through limewater 石灰水 | turns milky |
| chlorine 氯气 ($\text{Cl}_2$) | damp litmus paper | bleached white |
| hydrogen 氢气 ($\text{H}_2$) | a lighted splint | burns with a squeaky pop |
| oxygen 氧气 ($\text{O}_2$) | a glowing splint | relights |
| sulfur dioxide ($\text{SO}_2$) | acidified potassium manganate(VII) | purple colour fades |
Flame tests
A flame test 焰色试验 identifies some metal cations by the colour they give to a flame:
| Cation | Flame colour |
|---|---|
| lithium 锂 ($\text{Li}^+$) | red |
| sodium 钠 ($\text{Na}^+$) | yellow |
| potassium 钾 ($\text{K}^+$) | lilac (purple) |
| calcium ($\text{Ca}^{2+}$) | orange-red |
| barium 钡 ($\text{Ba}^{2+}$) | light green |
| copper(II) ($\text{Cu}^{2+}$) | blue-green |
探索
离子和气体测试实验
将测试观察结果与存在的离子或气体匹配。
词汇
训练
| English | 中文 | 拼音 |
|---|---|---|
| anion/ˈænaɪən/ | 阴离子 | yīn lí zǐ |
| carbonate/ˈkɑːbəneɪt/ | 碳酸根离子 | tàn suān gēn lí zǐ |
| carbon dioxide/ˈkɑːbən daɪˈɒksaɪd/ | 二氧化碳 | èr yǎng huà tàn |
| chloride/ˈklɔːraɪd/ | 氯离子 | lǜ lí zǐ |
| nitric acid/ˈnaɪtrɪk ˈæsɪd/ | 硝酸 | xiāo suān |
| silver nitrate/ˈsɪlvə ˈnaɪtreɪt/ | 硝酸银 | xiāo suān yín |
| bromide/ˈbrəʊmaɪd/ | 溴离子 | xiù lí zǐ |
| iodide/ˈaɪədaɪd/ | 碘离子 | diǎn lí zǐ |
| nitrate/ˈnaɪtreɪt/ | 硝酸根离子 | xiāo suān gēn lí zǐ |
| aluminium/ˌæljʊˈmɪnɪəm/ | 铝 | lǚ |
| sodium hydroxide/ˈsəʊdɪəm haɪˈdrɒksaɪd/ | 氢氧化钠 | qīng yǎng huà nà |
| ammonia/æˈməʊnɪə/ | 氨气 | ān qì |
| sulfate/ˈsʌlfeɪt/ | 硫酸根离子 | liú suān gēn lí zǐ |
| barium nitrate/ˈbeərɪəm ˈnaɪtreɪt/ | 硝酸钡 | xiāo suān bèi |
| sulfite/ˈsʌlfaɪt/ | 亚硫酸根离子 | yà liú suān gēn lí zǐ |
| potassium manganate(VII)/pəˈtæsɪəm ˈmæŋɡəneɪt/ | 高锰酸钾 | gāo měng suān jiǎ |
| cation/ˈkætaɪən/ | 阳离子 | yáng lí zǐ |
| precipitate/prɪˈsɪpɪteɪt/ | 沉淀 | chén diàn |
| ammonium/æˈməʊnɪəm/ | 铵 | ǎn |
| calcium/ˈkælsɪəm/ | 钙 | gài |
| chromium/ˈkrəʊmɪəm/ | 铬 | gè |
| copper/ˈkɒpə/ | 铜 | tóng |
| iron/ˈaɪən/ | 铁 | tiě |
| zinc/zɪŋk/ | 锌 | xīn |
| litmus/ˈlɪtməs/ | 石蕊 | shí ruǐ |
| limewater/ˈlaɪmwɔːtə/ | 石灰水 | shí huī shuǐ |
| chlorine/ˈklɔːriːn/ | 氯气 | lǜ qì |
| hydrogen/ˈhaɪdrədʒn/ | 氢气 | qīng qì |
| oxygen/ˈɒksɪdʒn/ | 氧气 | yǎng qì |
| flame test/fleɪm test/ | 焰色试验 | yàn sè shì yàn |
| lithium/ˈlɪθɪəm/ | 锂 | lǐ |
| sodium/ˈsəʊdɪəm/ | 钠 | nà |
| potassium/pəˈtæsɪəm/ | 钾 | jiǎ |
| barium/ˈbeərɪəm/ | 钡 | bèi |
12.5
考试技巧
English
- Pick apparatus by the measurement: a burette or pipette for accurate volumes, a measuring cylinder for a rough volume, a gas syringe for a gas volume, a balance for mass.
- $R_f = \dfrac{\text{distance moved by the substance}}{\text{distance moved by the solvent}}$, so it is always less than 1. A pure substance gives a single spot.
- Learn the anion tests: a carbonate fizzes and the gas turns limewater milky; halides with silver nitrate give a chloride white, bromide cream, iodide yellow precipitate; a sulfate gives a white precipitate with barium nitrate.
- Learn the gas tests: hydrogen gives a squeaky pop, oxygen relights a glowing splint, carbon dioxide turns limewater milky, chlorine bleaches damp litmus, ammonia turns damp red litmus blue.
- For cations, add sodium hydroxide and read the precipitate colour: copper(II) light blue, iron(II) green, iron(III) red-brown.
该知识点的互动课程
逐步完成，配合即时检查练习。