HKCE Chemistry Presented by 6B Law Sze Yeung

Exam Format Two papers Paper I – Long Questions (64%) Time allowed: 1hr 45mins 7-8 short questions (1 essay), 3-4 long questions (1 essay)

Paper II – Multiple-Choice Questions (36%) Time allowed: 1hr 50 questions

Time allocation Paper 1 1 hr and mins for answering questions, mins for checking. Paper 2 45 mins for answering questions, 15 mins for checking

Things to be memorized Definitions of some chemical terms Color of ions Properties of groups in the periodic table Different uses and properties of metals Different methods of extracting metals Metal reactivity series Solubility of ionic compounds

Things to be memorized E.C.S Uses and properties of chlorine and sulphur dioxide Principle of fractional distillation Monomers and usage of different polymers Uses and properties of detergents Separation and tests for chemicals

Green Chemistry Memorize : – different renewable energy resources Pros and cons – different measures to reduce pollution Pros and cons

Definitions are always worth remembering. Try memorising them ALL, since these marks are easy enough to secure

Experiment Pay attention on practical skills – know the steps of experiments (especially for volumetric analysis) – know how to draw experimental setup – know how to suggest and explain experimental precautions

Experiment Do not make stupid mistakes: – Closed system in heating or heating under reflux – Stopper completely inserted into the mouth of conical flask – Heating flammable chemicals directly under bunsen flame with no water bath or oil bath – Unreasonable position of water level and test tube when collecting gases – Delivery tube in wrong position – Drawing lines that are nonsense, etc. You should also be familiarized with the reason WHY they are wrong as they are frequently asked.

Calculation Recite formulas if you cannot handle chemical calculations well How to solve questions that are paragraph long? – Write all chemical equations related – Start at the back of the question and calculate backward

Essay Chemical bonding and structures uses and properties of different chemicals (Comparison) e.g.(Cl, H2SO4, organic compounds, detergents) procedure and precaution of experiment Environmental protection Detection and separation

Essay Paragraphing is important 6 marks for content – E.g. 3 main pts, then 2 marks each Spend at most 10 minutes for answering 1 essay

Other important points PLEASE recite the solubility of ionic compounds!!!!!!!!!!!!!! Be sensitive to color changes Ionic equations Physical states must be written Solids cannot be written as ions For instance, the correct ionic equation for the reaction between Ag+(aq) and Cl-(aq) is: Ag+ (aq) + Cl- (aq) → AgCl(s)

Other important points Meaning of reversible reactions Difference between strength and concentration Carbon atoms have 4 bonds – You should count each of them to ensure that you have drawn the correct structure of the molecule

Other important points Chlorine and concentrated sulphuric acid are oxidising agents, while sulphur dioxide is a reducing agent Difference between chlorine bleach and chlorine water – Chlorine water is acidic while chlorine bleach is alkaline ＋ / － signs in oxidation number Opposite polarities between electrodes – For chemical cell, cathode is ＋ while anode is － ; and as for electrolytic cell, cathode is － while anode is ＋

Past Paper Start working on past exam questions NOW!!!!!!!!!!! Complete the past exam questions from 1990 to 2002 by topic at least ONCE before the end of January – For conventional questions, you NEED NOT write out the answer, just organise it in you mind and read it out and check your answer.

Past Paper Redo the questions that you answered incorrectly before for the second time For the third time, just read the questions and think how to answer it. Finish (by year) during your study leave

Do not count on and recite the marking scheme blindly Although they are precise and accurate, some of the requirements in the questions you face may be different from the one you memorised Read the instructions and questions carefully during your examination, or you may lose so many marks that cost a grade!

Start your revision NOW