chemistry

• CSEC® Chemistry


  Caribbean Secondary Education Certificate examination in Chemistry

  
• This book is a concise revision course for students studying for the CSEC® Chemistry examination

  
• The CSEC® Chemistry syllabus is available online at http://cxc-store.com
• Sections covered in this book

  • Chapters 1 to 13: Principles of Chemistry
  • Chapters 14 to 17: Organic Chemistry
  • Chapters 18 to 24: Inorganic Chemistry
• At the end of each chapter or section, there are revision questions to test knowledge and understanding
• At the end of Chapters 13, 17 and 24, there are exam-style questions to help prepare for the examination
• Paper 01


  1 1/2 hour multiple choice paper with 60 questions, each worth 1 mark
• Paper 02


  2 1/2 hour structured and extended-response paper, divided into Sections A and B
• Sections in Paper 02

  • Section A: 3 compulsory structured questions
  • Section B: 3 compulsory extended-response questions
• Paper 02 is worth a total of 100 marks
• The examination evaluates performance using 3 profiles: Knowledge and comprehension, Use of knowledge, Experimental skills
• The second part will possibly test your knowledge of tests to identify cations, anions and gases, and there may be a third part which tests your planning and designing skills
• Questions 2 and 3

  • Each worth 15 marks
  • Begin with some kind of stimulus material, such as a diagram or a table, which you will be asked questions about
• Section B


  • Consists of three compulsory extended-response questions, each worth 15 marks
  • Require a greater element of essay writing in their answers than those in Section A
• A total of 100 marks is available for Paper 02 and the time allowed is 150 minutes
• Successful revision


  1. Begin your revision early

  2. Plan a revision timetable to cover this period

  3. Revise in the evenings, at weekends, during the Easter vacation and during study leave

  4. Study during two of the three sessions of the day, do something non-academic and relaxing during the third

  5. Revise every topic in the syllabus

  6. Learn the topics in order

  7. Revise in a quiet location without any form of distraction

  8. Sit up to revise, preferably at a table
• Methods to learn your work


  • Read the topic several times, then close the book and try to write down the main points
  • Summarise the main points of each topic on flash cards
  • Draw simple diagrams with annotations, flow charts and spider diagrams
  • Practise drawing and labelling simple line diagrams of apparatus
  • Practise writing equations
• Memory aids


  • Acronyms
  • Mnemonics
  • Associations between words
• Successful examination technique


  1. Read the instructions at the start of each paper very carefully

  2. Read through the entire paper before you begin to answer any of the questions

  3. Read each question at least twice before beginning your answer

  4. Underline the important words in each question

  5. Re-read the question when you are part way through your answer

  6. Give precise and factual answers

  7. Use correct scientific terminology

  8. Balance all chemical equations and ensure that you give the correct state symbols

  9. Show all working and give clear statements when answering questions that require calculations

  10. Give every numerical answer the appropriate unit

  11. Use bullets to make each separate point clear

  12. Watch the time as you work

  13. Check over your answers when you have completed all the questions

  14. Remain in the examination room until the end of the examination
• Key terms used on examination papers

  • Account for
  • Calculate
  • Compare
  • Construct
  • Contrast
  • Deduce
  • Define
  • Describe
  • Determine
  • Discuss
  • Distinguish between or among
  • Evaluate
  • Explain
  • Illustrate
  • Justify
  • Outline
  • Predict
  • Relate
  • State or list
  • Suggest
  • Tabulate
• Drawing tables


  • Neatly enclose the table and draw vertical and horizontal lines
  • Give the correct column headings and units
  • Give the appropriate number of decimal places
  • Give the table an appropriate title
• Drawing graphs


  • Plot the manipulated variable on the x-axis and the responding variable on the y-axis
  • Choose appropriate scales and use as much of the graph paper as possible
  • Enter numbers along the axes and label each axis, including relevant units
  • Use a small dot surrounded by a small circle to plot each point
  • Plot each point accurately
  • Draw a smooth curve or straight line of best fit
  • Give the graph an appropriate title
• School-Based Assessment (SBA) is an integral part of your CSEC® examination and is worth 20% of your final examination mark
• SBA assessments


  • Carried out in your school by your teacher during Terms 1 to 5 of your two-year programme
  • Carried out during normal practical classes and not under examination conditions
  • Assessments will be made of Manipulation and Measurement, Observation, Recording and Reporting, Planning and Designing, and Analysis and Interpretation
• You will be required to keep a practical workbook in which you record all of your practical work and this may then be moderated externally by CXC
• Gases diffuse


  1. Ammonia particles

  2. Hydrogen chloride particles

  3. Diffuse very quickly

  4. Particles diffuse quickly

  5. Along the lube

  6. Along the tube
• Cotion wool


  • Soaked in concentrated ammonia
  • Soaked in concentrated hydrochloric acid
• Potassium manganate(VII) crystal


  When placed in water, it dissolves to produce a uniformly purple solution
• Dissolving of potassium manganate(VII) crystal


  Particles separate from each other and diffuse through the spaces between the water particles until they are evenly distributed
• Osmosis


  The movement of water molecules through a differentially permeable membrane from a solution containing a lot of water molecules, e.g. a dilute solution (or water), to a solution containing fewer water molecules, e.g. a concentrated solution
• Osmosis explained


  1. Water particles diffuse through the pores in the membrane into the concentrated solution causing its volume to increase

  2. Sucrose particles try to diffuse through the membrane into the dilute solution, but they are unable to pass through the pores

  3. The level of the concentrated solution rises due to its increased volume
• The membranes of living cells are differentially permeable and the cytoplasm inside the cells contains about 80% water
• Effect of water on living tissue

  1. When a strip of living tissue (such as paw-paw) is placed in water, water molecules move into the cells by osmosis. Each cell swells slightly, and the strip increases in length and becomes rigid.

  2. When the strip is placed in a concentrated sodium chloride solution, water molecules move out of the cells by osmosis. Each cell shrinks slightly, and the strip decreases in length and becomes softer.
• Uses of osmosis


  • To control garden pests
  • To preserve food
• How salt controls garden pests

  When salt (sodium chloride) is sprinkled on slugs and snails, it dissolves in the moisture around their bodies forming a concentrated solution. Water inside their bodies then moves out by osmosis and into the solution. The slugs and snails die from dehydration if their bodies lose more water than they can tolerate.
• How salt and sugar preserve food

  1. They draw water out of the cells of the food by osmosis. This prevents the food from decaying because there is no water available in the cells for the chemical reactions which cause the decay.

  2. They draw water out of microorganisms (bacteria and fungi) by osmosis. This prevents the food from decaying because it inhibits the growth of the microorganisms that cause the decay.
• Types of particles that make up matter

  • Atoms
  • Molecules
  • Ions
• Atom


  The smallest units of a chemical element which have all the characteristics of the element
• Molecule


  Groups of two or more atoms bonded together and which can exist on their own
• Ion


  Electrically charged particles, which may be formed from a single atom or from groups of two or more atoms bonded together