AS AQA A-level Chemistry Unit 5 Past Paper Insert January 2019 | AS AQA A-level化学 Unit 5 2019年1月试卷插页解析

📚 AS AQA A-level Chemistry Unit 5 Past Paper Insert January 2019 | AS AQA A-level化学 Unit 5 2019年1月试卷插页解析

The January 2019 Unit 5 insert for AQA A-level Chemistry is more than just a periodic table – it is a carefully selected set of data designed to support your calculations and reasoning across many topics. In this article, we break down every component of the insert, explain exactly how to use each piece of data, and highlight common pitfalls that students encounter.

2019年1月AQA A-level化学Unit 5试卷的插页不仅仅是一张周期表，它是一组精心选择的数据，旨在支持你在许多主题上的计算与推理。在本文中，我们将分解插页的每一个组成部分，解释如何使用每一组数据，并指出学生经常遇到的陷阱。

1. What Is the Insert? | 插页是什么？

The insert is an official AQA document provided with the examination paper. It contains the periodic table, physical constants, and additional data tables that vary by paper. For Unit 5 (January 2019), the insert focuses on data relevant to thermodynamics, redox chemistry, and transition metal chemistry.

插页是AQA随试卷提供的官方文件。它包含周期表、物理常数以及随试卷而变化的附加数据表。对于Unit 5（2019年1月），插页侧重于热力学、氧化还原化学和过渡金属化学相关的数据。

You are allowed to refer to the insert throughout the exam. Do not memorise the data – instead, learn how to locate and apply it quickly.

考试期间你可以随时查看插页。不要死记数据，而是学会快速定位并应用它们。

2. The Periodic Table: Layout and Key Numerical Data | 周期表：布局与关键数值数据

The periodic table on the insert shows atomic numbers, relative atomic masses, and electron configurations for each element. For transition metals, the atomic masses are given in square brackets, indicating the most stable isotope.

插页上的周期表显示了每个元素的原子序数、相对原子质量和电子构型。对于过渡金属，相对原子质量用方括号给出，表示最稳定的同位素。

For example, iron (Fe) has a relative atomic mass of 55.8 and an electronic configuration of [Ar] 3d⁶4s². In exam questions, use the provided atomic masses rather than your memory, as values may be rounded differently.

例如，铁（Fe）的相对原子质量为55.8，电子构型为[Ar] 3d⁶4s²。在考试题目中，请使用提供的原子质量，而不是凭记忆，因为数值可能有不同的舍入。

The table includes elements up to Z=119, but only those needed for the syllabus are highlighted.

表中包括至Z=119的元素，但仅突出显示教学大纲所需的元素。
For transition metals, the 3d and 4s orbitals are both shown. Remember that 4s is filled before 3d, but ionisation removes 4s electrons first.

对于过渡金属，同时显示了3d和4s轨道。记住4s先于3d填充，但电离时先失去4s电子。

3. Physical Constants and Unit Conversions | 物理常数与单位换算

The insert provides constants such as Avogadro’s constant (L = 6.022 × 10²³ mol⁻¹) and the ideal gas equation constant (R = 8.31 J K⁻¹ mol⁻¹). These are essential for mole calculations and gas law problems.

插页提供了诸如阿伏加德罗常数（L = 6.022 × 10²³ mol⁻¹）和理想气体方程常数（R = 8.31 J K⁻¹ mol⁻¹）等常数。这些对于摩尔计算和气体定律问题至关重要。

Always check units. Energies in thermodynamics are given in kJ mol⁻¹, but gas constant R is in J K⁻¹ mol⁻¹. Convert kJ to J or divide by 1000 before using in equations.

始终检查单位。热力学中的能量单位是kJ mol⁻¹，但气体常数R的单位是J K⁻¹ mol⁻¹。在代入方程前，需将kJ转换为J，或除以1000。

pV = nRT → n = pV / RT

In the Jan 2019 paper, a question asked students to calculate the volume of gas produced using R = 8.31. Many students forgot to convert cm³ to m³, losing method marks.

在2019年1月的试卷中，有一题要求学生使用R = 8.31计算产生的气体体积。许多学生忘记将cm³转换为m³，从而损失了方法分。

4. Ionisation Energies and Periodic Trends | 电离能及其周期性趋势

The insert includes a table of successive ionisation energies for a few selected elements, but more commonly, the periodic table itself is used to predict trends in first ionisation energy.

插页包含几个选定元素的逐级电离能表格，但更常见的是，利用周期表本身预测第一电离能的趋势。

First ionisation energy increases across a period due to increasing nuclear charge, and decreases down a group due to increasing atomic radius and electron shielding.

第一电离能在一个周期内随核电荷增加而增大，在一个族内随原子半径和电子屏蔽增加而减小。

When a sudden jump in successive ionisation energies appears, it indicates that electrons are being removed from a stable, filled shell. For example, aluminium has ionisation energies: 578, 1817, 2745, 11577 kJ mol⁻¹. The large jump from 2745 to 11577 shows removal of a core electron from the n=2 shell.

当逐级电离能出现突然跃升时，表明电子正从稳定的填充壳层中移除。例如，铝的电离能为：578、1817、2745、11577 kJ mol⁻¹。从2745到11577的巨大跃升表明核心电子从n=2壳层被移除。

Use the data on the insert to deduce the group of an element from its successive ionisation energies.

使用插页上的数据，通过逐级电离能推断元素所在的族。
Remember that second ionisation energy is alway higher than the first because the electron is removed from a positive ion.

记住，第二电离能总是高于第一电离能，因为电子是从正离子中移除的。

5. Electronegativity and Bonding | 电负性与成键

Although electronegativity values are not always printed on the insert, the periodic table allows you to compare electronegativity trends. Assign values: fluorine (4.0), oxygen (3.5), nitrogen (3.0), carbon (2.5).

虽然电负性数值不总是印在插页上，但周期表允许你比较电负性趋势。赋予数值：氟（4.0）、氧（3.5）、氮（3.0）、碳（2.5）。

In the Jan 2019 insert, a diagram of the periodic table shaded by electronegativity was provided. This supported a question on bond polarity in organic compounds.

在2019年1月的插页中，提供了一张按电负性深浅着色的周期表。这支持了关于有机化合物中键极性的一道题目。

The difference in electronegativity (Δχ) between two atoms determines whether the bond is covalent (Δχ < 0.4), polar covalent (0.4 – 1.7), or ionic (Δχ > 1.7). Use this rule when asked to classify bonding.

两个原子之间的电负性差（Δχ）决定键是共价键（Δχ < 0.4）、极性共价键（0.4 – 1.7）还是离子键（Δχ > 1.7）。在要求分类键合类型时，使用这条规则。

Δχ = χ₂ − χ₁

6. Standard Electrode Potentials | 标准电极电势

For Unit 5, the insert provides a table of standard electrode potentials (Eθ) for common half-reactions. These are listed in alphabetical order of element, not by electrochemical series. You must learn to sort them by numerical value when constructing cell diagrams.

对于Unit 5，插页提供了常见半反应的标准电极电势（Eθ）表。这些按元素字母顺序排列，而不是按电化学序列。在构建电池图时，你必须学会按数值大小排序。

The most negative Eθ values are stronger reducing agents, while the most positive are stronger oxidising agents. Electrons flow from the negative electrode (anode) to the positive electrode (cathode).

最负的Eθ值是更强的还原剂，而最正的是更强的氧化剂。电子从负电极（阳极）流向正电极（阴极）。

To calculate the cell potential, use: Eθcell = Eθ(reduction) − Eθ(oxidation) or, equivalently, the more positive electrode potential minus the more negative.

计算电池电势用：Eθcell = Eθ(还原) − Eθ(氧化)，或等价于更正的电势减去更负的电势。

Half-reaction	Eθ / V
Cl₂ + 2e⁻ → 2Cl⁻	+1.36
Fe³⁺ + e⁻ → Fe²⁺	+0.77
Zn²⁺ + 2e⁻ → Zn	−0.76

In the Jan 2019 exam, students were asked to combine Fe³⁺/Fe²⁺ and Cl₂/Cl⁻ half-cells. The cell potential is 1.36 − 0.77 = +0.59 V, indicating a spontaneous reaction.

在2019年1月的考试中，学生被要求组合Fe³⁺/Fe²⁺和Cl₂/Cl⁻半电池。电池电势为1.36 − 0.77 = +0.59 V，表明反应自发进行。

7. Thermodynamic Data: Enthalpies and Entropies | 热力学数据：焓与熵

The insert includes a table of standard enthalpies of formation (ΔfHθ) and standard molar entropies (Sθ) for selected substances. This data is crucial for calculating ΔHθ, ΔSθ, and ΔGθ.

插页包含选定物质的标準生成焓（ΔfHθ）和标準摩尔熵（Sθ）表。这些数据对于计算ΔHθ、ΔSθ和ΔGθ至关重要。

The key equations are:

关键方程是：

ΔHθ = ΣΔfHθ(products) − ΣΔfHθ(reactants)

ΔSθ = ΣSθ(products) − ΣSθ(reactants)

ΔGθ = ΔHθ − TΔSθ

Remember to convert ΔSθ from J K⁻¹ mol⁻¹ to kJ K⁻¹ mol⁻¹ by dividing by 1000 before using in Gibbs equation, since ΔHθ is in kJ.

记住，在吉布斯方程中使用前，将ΔSθ从J K⁻¹ mol⁻¹转换为kJ K⁻¹ mol⁻¹，即除以1000，因为ΔHθ的单位是kJ。

For a reaction to be feasible, ΔGθ must be negative. In Jan 2019, a question examined the thermal decomposition of limestone (CaCO₃). Using the insert data, students calculated ΔHθ and ΔSθ and then found the temperature above which ΔGθ becomes negative.

要使反应可行，ΔGθ必须为负。在2019年1月，一道题考查了石灰石（CaCO₃）的热分解。使用插页数据，学生计算了ΔHθ和ΔSθ，然后找到了ΔGθ变为负值所需的温度。

8. Using the Insert in Redox Titration Calculations | 在氧化还原滴定计算中使用插页

Redox titrations often require you to balance half-equations. The electrode potential table on the insert provides the half-equations and their standard potentials. For example, MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O is shown with Eθ = +1.51 V.

氧化还原滴定通常需要你配平半反应。插页中的电极电势表提供了半反应及其标准电势。例如，MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O，其Eθ = +1.51 V。

In a titration, you use mole ratios from the balanced equation. If the insert gives you the half-equation, you still need to combine two half-equations and cancel electrons to get the overall equation.

在滴定中，你使用配平方程中的摩尔比。如果插页给你半反应，你仍然需要将两个半反应结合并消去电子，得到总方程。

A typical Jan 2019 question involved the titration of Fe²⁺ with acidified KMnO₄. The half-equations from the insert are:

一个典型的2019年1月题目涉及用酸化的KMnO₄滴定Fe²⁺。来自插页的半反应为：

MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O

Fe³⁺ + e⁻ → Fe²⁺

Multiply the iron half-equation by 5 and add to the manganate half-equation to obtain the overall ionic equation.

将铁半反应乘以5，并与高锰酸根半反应相加，得到总离子方程式。

9. Common Pitfalls When Using the Insert | 使用插页时的常见错误

Even with the insert in front of you, students make avoidable errors. Here is a list of the most frequent pitfalls, with advice on how to avoid them.

即使插页就在眼前，学生们也会犯一些可避免的错误。以下是常见错误的列表及避免建议。

Using atomic masses rounded to whole numbers instead of the precise values given on the insert. Always use the exact value shown.

使用四舍五入到整数的原子质量，而不是插页上给出的精确值。始终使用显示的精确值。
Forgetting to convert units when using the ideal gas equation or Gibbs free energy. Check whether the data is in J or kJ.

在使用理想气体方程或吉布斯自由能时忘记转换单位。检查数据单位是J还是kJ。
Misreading the electrode potential table because the half-reactions are alphabetical, not electrochemical. You must sort them by Eθ value when calculating cell EMF.

因为电极电势表按字母顺序而非电化学顺序排列而误读。在计算电池电动势时，必须按Eθ值排序。
Using ΔHθ instead of ΔSθ when calculating entropy change. Read the table headings carefully.

在计算熵变时误用了ΔHθ而不是ΔSθ。仔细阅读表头。
Ignoring state symbols in enthalpy calculations, which affect the values of ΔHθ.

在焓计算中忽略状态符号，这会影响ΔHθ的值。

10. Worked Example: Jan 2019 Unit 5 Insert Question | 例题解析：2019年1月Unit 5插页题目

Let us reconstruct a typical question based on the January 2019 insert. The insert provided the following standard entropies: Sθ (C(s)) = 5.7 J K⁻¹ mol⁻¹, Sθ (O₂(g)) = 205.1 J K⁻¹ mol⁻¹, Sθ (CO₂(g)) = 213.7 J K⁻¹ mol⁻¹. Also, ΔfHθ (CO₂) = −393.5 kJ mol⁻¹.

让我们重建一道基于2019年1月插页的典型题目。插页提供了以下标准熵：Sθ（C(s)）= 5.7 J K⁻¹ mol⁻¹，Sθ（O₂(g)）= 205.1 J K⁻¹ mol⁻¹，Sθ（CO₂(g)）= 213.7 J K⁻¹ mol⁻¹。另外，ΔfHθ（CO₂）= −393.5 kJ mol⁻¹。

Question: Calculate ΔSθ for the combustion of carbon at 298 K, and then determine ΔGθ for the same reaction.

题目：在298 K下计算碳燃烧的ΔSθ，然后确定同一反应的ΔGθ。

Solution:

解答：

ΔSθ = Sθ(CO₂) − [Sθ(C) + Sθ(O₂)] = 213.7 − (5.7 + 205.1) = 2.9 J K⁻¹ mol⁻¹

The entropy change is small and positive because one molecule of gas produces one molecule of gas, but the molar entropy of CO₂ is higher than O₂ due to its larger molecular size.

熵变很小且为正，因为一分子气体产生一分子气体，但CO₂的摩尔熵高于O₂，因为其分子尺寸更大。

Now use ΔGθ = ΔHθ − TΔSθ. Convert ΔSθ to kJ: 2.9 / 1000 = 0.0029 kJ K⁻¹ mol⁻¹.

现在使用ΔGθ = ΔHθ − TΔSθ。将ΔSθ转换为kJ：2.9 / 1000 = 0.0029 kJ K⁻¹ mol⁻¹。

ΔGθ = −393.5 − 298 × 0.0029 = −393.5 − 0.864 = −394.4 kJ mol⁻¹

The very negative ΔGθ confirms the combustion of carbon is strongly spontaneous at room temperature.

非常负的ΔGθ证实碳在室温下的燃烧是高度自发的。

This exact style of calculation appears frequently in Unit 5. The insert provided all necessary data; you simply need to read the correct values and apply the equations.

这种风格的题目在Unit 5中经常出现。插页提供了所有必要的数据；你只需读出正确的值并应用方程即可。

11. Final Strategy for Exam Day | 考试日的最终策略

Before the exam, familiarise yourself with the layout of the insert. In the first five minutes, scan the data tables so you know exactly where each type of information is located.

考试前，熟悉插页的布局。在头五分钟内，扫描数据表，以便确切知道每种信息的位置。

When answering a question that requires a numerical value, underline the data on the insert you intend to use. This prevents careless transcription errors and shows the examiner a clear method.

回答需要数值的题目时，在插页上划出你打算使用的数据。这可以防止粗心的抄写错误，并向考官展示清晰的方法。

Practice with past papers from the same series. The January 2019 insert, like all others, rewards students who can move quickly between the periodic table, electrode potentials, and thermodynamic tables.

用同系列的真题练习。2019年1月的插页与其他一样，奖励那些能在周期表、电极电势和热力学表之间快速切换的学生。

Finally, remember that the insert is a tool, not a test of memory. You do not need to memorise any constant or electrode potential. Your job is to interpret and apply the data within the time limit.

最后，记住插页是工具，不是记忆测试。你不需要记住任何常数或电极电势。你的任务是在时限内解读和应用数据。

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AS AQA A-level Chemistry Unit 5 Past Paper Insert January 2019 | AS AQA A-level化学 Unit 5 2019年1月试卷插页解析