📚 Year 7 WJEC Chemistry: Exam Technique and Mark Schemes | Year 7 WJEC 化学答题技巧与评分标准
Mastering exam technique is just as important as knowing the science. In Year 7 WJEC Chemistry, marks are awarded not only for correct answers but also for how you present them. This guide explains key command words, mark scheme secrets, and practical strategies to help you achieve your best grade.
掌握答题技巧与掌握科学知识同样重要。在 Year 7 WJEC 化学考试中，得分不仅取决于答案正确，还取决于如何呈现答案。本指南将解释关键的指令词、评分标准的秘密以及实用的应试策略，帮助你取得最佳成绩。
1. Understanding Command Words | 理解指令词
WJEC exam questions use specific command words like 'state', 'describe', 'explain', and 'compare'. Knowing what each means is the first step to scoring full marks.
WJEC 考试题目使用特定的指令词，如“陈述”、“描述”、“解释”和“比较”。了解每个词的含义是获得满分的第一步。
'State' asks for a short, factual answer without reasoning. For example, 'State the colour of chlorine gas.' Answer: 'Green-yellow.'
“陈述”要求给出简短的事实性答案，无需推理。例如，“陈述氯气的颜色。”答案：“黄绿色。”
'Describe' requires you to say what you see or what happens, often in a sequence. It never asks 'why'. Example: 'Describe the changes when ice melts.' Answer: 'The solid turns into a liquid. The temperature stays at 0°C until all ice has melted.'
“描述”要求说出你看到什么或发生了什么，通常按顺序。它从不问“为什么”。示例：“描述冰融化时的变化。”答案：“固体变成液体。温度保持在 0°C 直到所有冰融化。”
'Explain' means give scientific reasons – you must use 'because'. If you see 'explain', always aim to write a cause-and-effect sentence. Example: 'Explain why iron rusts faster in salt water.' Answer: 'Salt water contains ions that speed up the flow of electrons, so rusting occurs more quickly.'
“解释”意味着给出科学原因——必须使用“因为”。如果看到“解释”，始终要写出因果句。示例：“解释为什么铁在盐水中生锈更快。”答案：“盐水含有离子，可以加速电子流动，因此生锈更快。”
'Compare' asks you to identify similarities and differences. Use linking words such as 'whereas' or 'both'. Example: 'Compare graphite and diamond.' Answer: 'Both are made of carbon atoms, but in graphite atoms are arranged in layers, making it soft, whereas diamond has a rigid structure, making it hard.'
“比较”要求找出相同点和不同点。使用“而”、“两者都”等连接词。示例：“比较石墨和金刚石。”答案：“两者都由碳原子组成，但石墨的原子分层排列，质地柔软，而金刚石结构坚固，质地坚硬。”
2. Reading the Question and Extracting Key Information | 阅读题目与提取关键信息
Always highlight the command word and any numbers, units, or data given in the question. A common mistake is to ignore small words like 'not' or 'only'.
始终标亮指令词以及题目中给出的任何数字、单位或数据。一个常见错误是忽略如“不”或“仅”等小词。
If the question provides a table or graph, read the axes and units carefully. Point your finger to the exact data point before answering. For example: 'What was the temperature after 30 seconds?' – trace up from 30 s on the time axis to the curve.
如果题目提供了表格或图表，请仔细阅读坐标轴和单位。在回答之前，用手指指向确切的数据点。例如：“30 秒后的温度是多少？”——从时间轴上 30 秒处向上追踪到曲线。
Look out for 'give one reason' or 'name two substances'. The number tells you how many points to include. WJEC mark schemes award one mark per correct point; if you list three but the question asks for two, only the first two might be marked.
注意“给出一个理由”或“写出两种物质”。数字提示你需要包含多少个要点。WJEC 评分标准每个正确点给一分；如果问题要求两个而你列出了三个，可能只批阅前两个。
3. Using Scientific Terminology Accurately | 准确使用科学术语
Chemistry has precise language. Avoid everyday words when a scientific term is expected. For instance, say 'evaporation' not 'drying up', and 'dissolve' not 'melt away'.
化学有精确的语言。当期望使用科学术语时，避免使用日常词语。例如，说“蒸发”而不是“变干”，说“溶解”而不是“融化掉”。
Be careful with element symbols: cobalt is Co (capital C, small o), but carbon monoxide is CO (both capitals). Writing 'co' can lose marks because it is not a recognised symbol.
注意元素符号：钴是 Co（大写 C，小写 o），但一氧化碳是 CO（两个大写）。写成 “co” 会失分，因为它不是可识别的符号。
Use correct state symbols when describing changes of state: solid (s), liquid (l), gas (g), and aqueous (aq). Even in Year 7, you might be asked to label a diagram showing 'liquid water (l)' or 'steam (g)'.
在描述状态变化时使用正确的状态符号：固体 (s)、液体 (l)、气体 (g) 和水溶液 (aq)。即使在 Year 7，你也可能被要求标注示意图，显示“液态水 (l)”或“水蒸气 (g)”。
4. Describing Chemical Reactions | 描述化学反应
Many marks are earned by describing what is observed. Use all your senses – colour change, fizzing, heat given out, precipitate formed.
许多分数是通过描述观察到的现象获得的。动用所有感官——颜色变化、嘶嘶声、放热、形成沉淀。
You may need to write word equations. For example:
magnesium + oxygen → magnesium oxide
Use arrow (→), not equals sign. Always write the reactants first, then products.
你可能需要书写文字方程式。例如：
镁 + 氧气 → 氧化镁
使用箭头 (→)，而不是等号。始终先写反应物，然后写生成物。
If the question asks 'What is the difference between a physical and chemical change?' – a physical change is reversible and no new substance is made (e.g., melting), whereas a chemical change is usually irreversible and new substances are formed (e.g., rusting).
如果问题问“物理变化和化学变化的区别是什么？”——物理变化是可逆的，没有新物质生成（如融化），而化学变化通常是不可逆的，生成了新物质（如生锈）。
For heating or mixing, using proper terms: 'filtrate' not 'the water that came through', 'residue' for the solid left on filter paper. These terms appear in mark schemes.
对于加热或混合，使用恰当的术语：“滤液”而不是“流过来的水”，留在滤纸上的固体叫“残渣”。这些术语会出现在评分标准中。
5. Drawing Diagrams and Presenting Data in Tables | 绘制图表与用表格呈现数据
When drawing apparatus, use a sharp pencil and a ruler. Diagrams should be 2D, not 3D sketches, with clear labels on straight guidelines. Mark schemes often give a mark for a fully labelled diagram.
绘制仪器图时，使用削尖的铅笔和尺子。图表应为二维，而非三维草图，并在笔直的指引线上标注清晰。评分标准通常会对完全标注的图表给分。
Tables must have a title, and column headings must include units in brackets, e.g., 'Time (s)' and 'Temperature (°C)'. Never write units inside the data cells – only in the heading.
表格必须有标题，列标题必须包含括号中的单位，例如“时间 (s)”和“温度 (°C)”。切勿在数据单元格内写入单位——只在标题中写单位。
Use the correct scale for graphs; the plotted points should take up more than half the grid paper. Join points with a ruler or a smooth curve as appropriate. Label axes with quantity and unit.
图表要使用正确的比例；绘制的点应占据网格纸的一半以上。用尺子或光滑曲线适当连接各点。坐标轴上标注数量和单位。
6. Experimental Design: Variables and Fair Testing | 实验设计：变量与公平测试
You must identify independent, dependent, and control variables. Independent is what you change, dependent is what you measure, and controls are kept the same.
你必须识别自变量、因变量和控制变量。自变量是你改变的量，因变量是你测量的量，控制变量是保持不变的量。
Example: Investigating how temperature affects dissolving speed. Independent: temperature of water (20°C, 40°C, 60°C). Dependent: time for sugar to dissolve. Controls: mass of sugar, volume of water, stirring speed.
示例：研究温度如何影响溶解速度。自变量：水的温度（20°C, 40°C, 60°C）。因变量：糖溶解所需的时间。控制变量：糖的质量、水的体积、搅拌速度。
A fair test changes only one variable. WJEC mark schemes often reward the phrase 'to make it a fair test' or 'to ensure valid results'. Also, you might need to explain how to improve reliability: repeat the experiment and calculate a mean.
公平测试只改变一个变量。WJEC 评分标准经常会奖励“使其成为公平测试”或“确保结果有效”这样的表述。此外，你可能需要解释如何提高可靠性：重复实验并计算平均值。
7. Common Mistakes and How to Avoid Them | 常见错误与如何避免
Mistake 1: Not reading the question fully. Students often answer what they expect to see, not what is actually asked. Remedy: underline key terms and check after writing.
错误 1：没有全面阅读题目。学生常按预想作答，而非根据实际提问。对策：划出关键词，写完后核对。
Mistake 2: Missing units or using wrong ones. If you calculate a mass, always add g or kg. Volume: cm³ or mL. Temperature: °C. If the question provides units, use the same ones in your answer.
错误 2：遗漏单位或使用错误的单位。如果计算质量，务必添加 g 或 kg。体积：cm³ 或 mL。温度：°C。如果题目给出了单位，在你的答案中使用相同的单位。
Mistake 3: Not linking explanation to the specific context. If a question is about burning wood, do not talk about metal; use the substances given. Use 'it' clearly to refer back.
错误 3：解释没有与具体情境关联。如果问题关于燃烧木头，不要提到金属；使用给出的物质。清楚地使用“它”来回指。
Mistake 4: Confusing 'energy' with 'temperature'. Temperature is a measure of hotness, while energy is what is transferred. In mark schemes, saying 'heat energy' may be accepted, but avoid 'hot temperature'.
错误 4：混淆“能量”与
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