I scored 4A* for my AS Level in October 2013 and for my A Level in May 2014. One of the 4 subjects I took was Chemistry. My percentage uniform mark for Chemistry was 96% in AS Level and 93% in A Level. Here, I am sharing the tips for AS and A Level Chemistry. These tips are intended for students who are sitting for Cambridge International AS or A Level.
Tips for other Cambridge International AS and A Level subjects can be found here:
1. Studying tips
- When your teacher is teaching in class, pay attention to what your teacher says. Make sure you understand everything taught by your teacher. If you do not understand anything, ask your teacher or friends.
- You need notes or reference books that are complete. I recommend you to use my notes. You can download my notes here:
- When studying a chapter, read through all the explanations in my notes or in the reference book sentence by sentence. Make sure that you truly understand each sentence before moving on to the next sentence. Certain topics may require understanding of earlier topics, so make sure you understand those topics. You should also try to relate them to what your teacher had taught in college or school.
- You should be actively involved in all experiments carried out in college or school because this can help improve your practical skills which are essential for Paper 3 and Paper 5.
- Then, you have to remember everything that you understood. You can memorise the sentences in my notes or in the reference book, or you can also create your own sentences that have the same meaning and memorise them. If you create your own sentences, make sure that you do not change the original meaning, do not leave out any important points and do not change the important keywords and scientific terms. However, do not just memorise without understanding. Once you have understood, it will be quite easy to remember and you will be unlikely to forget any of the points.
- For certain facts, there may be no explanation for them so it is not possible to understand them. In that case, you have to remember and memorise those facts.
- For the calculations, you need to know how to apply what you have learnt and use the correct formula to solve the questions. Go through all the example questions in my notes or in the reference book. Make sure that you understand how every question is solved.
- You have to regularly revise every topics again and again. When revising, go through all the explanation, facts and examples for calculation questions in my notes or in the reference book. Make sure that you do not forget anything that you have understood previously. Regular and repeated revision will help you to remember all the explanation and facts for a long time.
- When you have understood all topics, you have to do past year A Level questions. After doing the questions, refer to the mark scheme and do self marking. Past year questions and mark schemes are available here:
- You should understand how the mark schemes are used. In the mark schemes for Chemistry, most marks are independent of any other marks, which means that they can be scored without other marks also being scored, unless otherwise stated by the mark scheme. If any scientific term is underlined or highlighted, it means that the exact term must be used in the answer and no other term is acceptable even if the meaning is the same, but grammatical variants of the term is accepted. If any non-scientific term is underlined or highlighted, it means that either the exact term or other terms with the same meaning must be used in the answer. If any words are placed in brackets, it means that the words need not be present in the answer for the mark to be scored. In the mark schemes, A means accept, I means ignore while R means reject.
- When doing revision before exam, you should first go through the subtopics that you think is more difficult or that you may have forgotten. Then, go through other topics as well if possible.
- To prepare for Chemistry Paper 3 and Paper 5, you should go through all the past year questions and the mark schemes. Find out how every question is marked and which points need to be included in the answers. The pattern of questions set is similar for every year and you should familiarise yourself with the pattern. Usually, the same type of questions will have similar mark scheme, so this can help you when answering exam questions. You should remember the answers for questions that are common.
2. Paper 1
- Read the question and all the options carefully. Write any rough workings on the question paper if you need to. Cancel off the options that you consider as definitely wrong. Then, choose the most suitable answer among the options.
3. Paper 2 and Paper 4
- When answering, read the question and all information given carefully. Make sure that you know what the question is asking for. Answer the questions based on your knowledge and understanding on the relevant topic in Chemistry. Certain questions may test you on more than one topics. For some questions, you may have to apply what you have learnt in Chemistry in order to answer them. You have to think carefully and relate the question to what you have learnt. You may also be asked to give your own opinions.
- When writing your answer, you can use the same or similar words or sentences as those in my notes or in the reference books if possible. However, sometimes you may need to make some changes in order to suit the question. You can also answer in your own sentences that have the same meaning. If the question asks on something that is not in my notes and the reference books (the question requires you to apply what you have learnt in Chemistry or give your own opinion), then you have to answer in your own sentences. For all questions, your answer must be specific and not too general. Give the most suitable answer according to the question.
- You should use the correct scientific terms in your answer. Do not replace them with other terms that are inappropriate, even if their meaning are the same. You should spell all scientific terms correctly. If you can't do so, try to spell it in such a way where it sounds the same as the actual term when read out. Marks are usually not deducted for spelling errors in scientific terms as long as it still sounds the same and that it is not easily confused with other terms. If you spell a non-scientific term wrongly or if you make grammatical errors in your answer, marks will not be deducted as long as the examiner can understand what you are writing. You are allowed to use suitable short forms in your answer, such as formula for chemical substances and symbols for units of physical quantities.
- It is not compulsory to answer in continuous writing form. You are allowed to answer in table form, point form or other suitable forms. In suitable cases, you can also use diagrams, equations or graphs in your answer.
- When answering questions on calculation, you should show all workings. You should not skip any important steps. You must also write the correct unit for the final answer if it is not provided. You are advised to write down the formula used to solve the question, even though it is not compulsory to do so. The number of marks allocated for the question usually shows the amount of working needed. 1 mark will be given for each important step and the final answer. Correct answer without working usually scores only 1 mark. If your final answer is wrong but some of your working is correct, you may still be given some marks. You are not allowed to write extra solutions or answers. If you do so and any of the answers or solutions is wrong, marks will be deducted. When copying figures from the question or from your answer for the previous part of the question, be careful not to copy wrongly. For a calculation question which requires you to use your answer from the previous question, even if your answer for the previous question is wrong and you use it for this question causing your answer for this question to be wrong, usually you will still get full marks for this question as long as your calculation for this question is correct. This is known as 'error carried forward'.
- Usually, you should give the final answer to 3 significant figures. Do not write your final answer as a fraction or in surd form. However, if the question asks you to give your answer to a specific number of significant figures, then you must follow the instruction, or if the question states that you must give your answer to a suitable number of significant figures, then the number of significant figures of your answer should be equal to the number of significant figures of the raw value used in the calculation with the least number of significant figures.
- For questions that require explanation or description, your answer must be very detailed. You are advised to answer in complete sentences so that your answer can be easily understood. The number of marks allocated for the question usually shows the number of points needed in your answer. 1 mark is given for each correct point. Do not miss out any important points in your answer. You are allowed to write extra points in your answer, but you must be careful not to write any points with wrong facts. Marks will only be given for the correct points. For points that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for points that contain wrong facts, marks may be deducted.
- For questions that do not require explanation or description, write the answer straight away. You need not answer in complete sentences. The number of marks allocated for the question usually shows the number of answers needed. If the question states the number of answers you have to write, then you are not allowed to write extra answers. If you do so, marks may not be given for the extra answers, and marks may be deducted if any of them is wrong. If the question does not state the number of answers you have to write, you are allowed to write extra answers, but you must be careful not to write any answer with wrong facts. Marks will only be given for the correct answers. For answers that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for answers that contain wrong facts, marks may be deducted.
- When drawing diagrams, make sure that all important details are included in the diagram you draw. You have to label correctly all parts in the diagram. Your diagram should be clear and neat.
4. Paper 3
- During the test, read the question and all information given carefully. Make sure that you understand the experiment given. Certain parts of the question require you to record the readings from the experiment in a table. You should draw the tables before carrying out the experiment so that you can record your readings in the table straight away during the experiment. Then, carry out the experiment by following the steps given in the question exactly. You need to apply your Chemistry practical skills when carrying out the experiment.
- Certain questions may require your knowledge and understanding in Chemistry to answer them. You may also need to give your own opinions. Your answer must be specific and not too general. Give the most suitable answer according to the question.
- When recording readings from an measuring instrument, the number of decimal places used should be equal to half of the smallest division of scale of the instrument (For example, if the instrument's smallest division of scale is 0.1, you should record the reading to the nearest 0.05, which is 2 decimal places.) For digital instruments (except digital stopwatch), the number of decimal places used should be the same as that shown on the display. The reading should be recorded to the nearest 1s for stopwatch (both analogue and digital). In all cases, do not give more or less number of decimal places. You must also write the correct units.
- For questions on titration, you should first perform a rough titration, then perform 2 accurate titrations. Record the initial burette reading and final burette reading for each titration, then calculate the titre. You should record everything in a table. All readings should be recorded to 2 decimal places. The titre for the 2 accurate titrations should not differ by more than 0.10cm3. Then, calculate the mean titre for the 2 accurate titrations. The mean should be given to 2 decimal places.
- When plotting graph, draw both the horizontal and vertical axis on the graph paper correctly. Label both axis correctly and state the unit (if any). Use a suitable scale for both axis and do not use any odd scales such as 3:10. Both the x-axis and y-axis need not start from 0 (unless otherwise stated by the question). The scales should be chosen such that the points plotted on graph cover at least half of the graph paper. Plot all points on the graph accurately. The points should be accurate to half a small square. For all the points, their diameter should not be larger than half a small square. Then, draw the correct straight line or curve. When drawing the straight line or curve, it should pass through all points on the graph if possible. If this is not possible, the line or curve should pass through as many points on the graph as possible, all the points should be close to it and the number of points above and below the line or curve should be almost equal. When determining the gradient of a straight-line graph, choose 2 points on the line and draw a triangle. The distance between the 2 points chosen should be at least half the length of the line.
- For questions on qualitative analysis, for each chemical test, you should use about 1cm depth or 2cm3 of each solution unless otherwise stated by the question. You have to record the full observations. State if there is any colour change or if precipitate forms. For any colour change, indicate both the initial and final colour, as well as the stage in which the change occurs if more than one reagents are added. If precipitate forms, state the colour of precipitate and whether it is soluble in excess of the reagent added, and if it is soluble state the colour of the solution formed. If you see any bubbles formed, it means that gas is released, and you should carry out gas tests to determine what the gas is. Only gas tests in the Qualitative Analysis Notes at the last page of question paper should be carried out. The gas can be any one of the 6 gases, but based on the type of reagents added and your experience in doing Chemistry practical work, you may be able to predict the type of gas released and thus choose the appropriate gas test to be carried out (For example, if a metal is added to an unknown solution and gas is released, it is likely that the solution is an acid and thus hydrogen gas is released, so you should carry out the gas test for hydrogen). State that effervescence occurs and state the observations of the gas test which is positive and the type of gas released. When determining the type of an unknown chemical, it should be based on your observations of the chemical tests carried out and refer to the Qualitative Analysis Notes at the last page of question paper.
- For any questions involving calculation, the number of significant figures of your answer should be equal to or one more than the number of significant figures of the raw value used in the calculation with the least number of significant figures. You should show all workings and do not skip any important steps. You must also write the correct unit for the final answer if it is not provided. You are not allowed to write extra solutions or answers. If you do so and any of the answers or solutions is wrong, marks will be deducted. For a calculation question which requires you to use your answer from the previous question, even if your answer for the previous question is wrong and you use it for this question causing your answer for this question to be wrong, usually you will still get full marks for this question as long as your calculation for this question is correct. This is known as 'error carried forward'.
- For questions that require explanation or description, your answer must be very detailed. You are advised to answer in complete sentences so that your answer can be easily understood. The number of marks allocated for the question usually shows the number of points needed in your answer. 1 mark is given for each correct point. Do not miss out any important points in your answer. You are allowed to write extra points in your answer, but you must be careful not to write any points with wrong facts. Marks will only be given for the correct points. For points that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for points that contain wrong facts, marks may be deducted.
- For questions that do not require explanation or description, write the answer straight away. You need not answer in complete sentences. The number of marks allocated for the question usually shows the number of answers needed. If the question states the number of answers you have to write, then you are not allowed to write extra answers. If you do so, marks may not be given for the extra answers, and marks may be deducted if any of them is wrong. If the question does not state the number of answers you have to write, you are allowed to write extra answers, but you must be careful not to write any answer with wrong facts. Marks will only be given for the correct answers. For answers that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for answers that contain wrong facts, marks may be deducted.
- When drawing diagrams, make sure that all important details are included in the diagram you draw. You have to label correctly all parts in the diagram. Your diagram should be clear and neat.
- For all questions, you should use the correct practical and scientific terms in your answer. Do not replace them with other terms that are inappropriate, even if their meaning are the same. You should spell all practical and scientific terms correctly. If you can't do so, try to spell it in such a way where it sounds the same as the actual term when read out. Marks are usually not deducted for spelling errors in practical and scientific terms as long as it still sounds the same and that it is not easily confused with other terms. If you spell other terms wrongly or if you make grammatical errors in your answer, marks will not be deducted for as long as the examiner can understand what you are writing. You are allowed to use suitable short forms in your answer, such as formula for chemical substances and symbols for units of physical quantities.
5. Paper 5
- When answering, read the question and all information given carefully. Make sure that you understand the experiment given and know what the question is asking for. Answer the questions based on the experiment and its observations and results. You may need to apply your Chemistry practical skills to answer some questions. Certain questions may require your knowledge and understanding in Chemistry to answer them. You may also need to give your own opinions. For all questions, your answer must be specific and not too general. Give the most suitable answer according to the question.
- You should use the correct practical and scientific terms in your answer. Do not replace them with other terms that are inappropriate, even if their meaning are the same. You should spell all practical and scientific terms correctly. If you can't do so, try to spell it in such a way where it sounds the same as the actual term when read out. Marks are usually not deducted for spelling errors in practical and scientific terms as long as it still sounds the same and that it is not easily confused with other terms. If you spell other terms wrongly or if you make grammatical errors in your answer, marks will not be deducted for as long as the examiner can understand what you are writing. You are allowed to use suitable short forms in your answer, such as formula for chemical substances and symbols for units of physical quantities.
- It is not compulsory to answer in continuous writing form. You are allowed to answer in table form, point form or other suitable forms. In suitable cases, you can also use diagrams, equations or graphs in your answer.
- For any questions involving calculation, the number of significant figures of your answer should be equal to or one more than the number of significant figures of the raw value used in the calculation with the least number of significant figures. If you are in doubt, give your answer to 3 significant figures. You should show all workings and do not skip any important steps. You must also write the correct unit for the final answer if it is not provided. You are not allowed to write extra solutions or answers. If you do so and any of the answers or solutions is wrong, marks will be deducted. For a calculation question which requires you to use your answer from the previous question, even if your answer for the previous question is wrong and you use it for this question causing your answer for this question to be wrong, usually you will still get full marks for this question as long as your calculation for this question is correct. This is known as 'error carried forward'.
- For questions that require explanation or description, your answer must be very detailed. You are advised to answer in complete sentences so that your answer can be easily understood. The number of marks allocated for the question usually shows the number of points needed in your answer. 1 mark is given for each correct point. Do not miss out any important points in your answer. You are allowed to write extra points in your answer, but you must be careful not to write any points with wrong facts. Marks will only be given for the correct points. For points that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for points that contain wrong facts, marks may be deducted.
- For questions that do not require explanation or description, write the answer straight away. You need not answer in complete sentences. The number of marks allocated for the question usually shows the number of answers needed. If the question states the number of answers you have to write, then you are not allowed to write extra answers. If you do so, marks may not be given for the extra answers, and marks may be deducted if any of them is wrong. If the question does not state the number of answers you have to write, you are allowed to write extra answers, but you must be careful not to write any answer with wrong facts. Marks will only be given for the correct answers. For answers that are irrelevant but does not contain wrong facts, no mark will be given or deducted. However, for answers that contain wrong facts, marks may be deducted.
- When drawing diagrams, make sure that all important details are included in the diagram you draw. You have to label correctly all parts in the diagram. Your diagram should be clear and neat.
- When plotting graph, draw both the horizontal and vertical axis on the graph paper correctly. Label both axis correctly and state the unit (if any). Use a suitable scale for both axis and do not use any odd scales such as 3:10. Both the x-axis and y-axis need not start from 0 (unless otherwise stated by the question). The scales should be chosen such that the points plotted on graph cover at least half of the graph paper. Plot all points on the graph accurately. The points should be accurate to half a small square. For all the points, their diameter should not be larger than half a small square. Then, draw the correct straight line or curve. When drawing the straight line or curve, it should pass through as many points on the graph as possible, all the points should be close to it and the number of points above and below the line or curve should be almost equal. However, usually one or more points on the graph are anomalous, which should be ignored when drawing the straight line or curve. The line or curve should not be deviated to accommodate them.
- For the question which asks you to suggest the reason for the anomalous points on the graph, common reasons are that a particular measurement is done before or after the moment it should be done, the actual value of a quantity is higher or lower than the measured value, incomplete oxidation/reduction, incomplete decomposition, loss of water/chemical, a compound has decomposed or other similar reasons. Note that these are only the general answers, but you have to give more specific answers based on the question.
Tips for other Cambridge International AS and A Level subjects can be found here: