1. GUIDELINES FOR ANSWERING PAPER 3

2. Structure Question 1or 2 to test the mastery of 11 Scientific Skills 1. Observing 2. Classifying 3. Inferring 4. Measuring (burette, stopwatch, thermometer, voltmeter) 5. Predicting 6. Communicating( e.g construct table and draw graph) 7. Space-Time Relationship 8. Interpreting Data 9. Defining Operationally 10. Controlling Variables 11. Hypothesizing

3. Operational definition is a statement that contains: 1. what you do/procedure 2. what you see/observation

4. Operational definition Example: 1. When acid is added into latex, white solid is formed. When acid is added into latex, latex coagulated.- wrong 2. When the higher the concentration sodium thiosulphate solution is added into sulphuric acid, time taken for `X~ mark to disappear from sight is shorter.

5. Operational definition Example: 3. When iron nail is coiled with copper and immersed into jelly mixed with potassium hexacyanoferrate(III) and phenolphthalein solution, blue spot/colouration is formed.

6. Operational definition for What you do What is observed 1.Rusting of iron - When an iron nail coiled with a less electropositive metal is immersed in hot agar- agar added with potassium hexacyanoferrate (III) solution, Blue spots are formed 2. Coagulation of latex - When acid is added to latex White solid is formed

7. Operational definition for What you do What is observed 3. Reactivity of Group 1 elements When a metal which is lower in Group 1 is put in a basin half filled with water Brighter flame is formed 4. Precipitation of silver chloride When silver nitrate solution is added to sodium chloride solution White solid is formed 5. Voltaic cell When two different metals are dipped into an electrolyte The needle of the voltmeter deflects//Voltmeter shows a reading

8. Operational definition for What you do What is observed 6. An acid When a blue litmus paper is dipped into a substance which is dissolved in water, Blue litmus paper turns red 7. Heat of combustion When 1 mol of fuel is burnt in excess oxygen Temperature rises//Thermometer reading increases

9. Operational definition for What you do What is observed 8. Hardness of alloy When a weight is dropped on a steel ball bearing taped on an alloy block Diameter of dent formed is smaller

10. Hypothesis: Statement that relates the manipulated variable followed by responding variable with direction. Example: 1.The higher temperature of the reactant the higher the rate of reaction – 3 marks 2. Hexene decolourised brown bromine water but hexane does not decolourised brown bromine water.

11. Hypothesis: Statement that relates the manipulated variable followed by responding variable with direction. Example: 3. When acid is added into latex, latex coagulates, when ammonia is added into latex, latex cannot coagulates 4. Question 3 (essay) Test the Mastery of Planning Experiment.

12. ExperimentMVRVHypothesis (MV→RV) Electrolysis of solution with different concentrati on using carbon electrodes Size of calcium carbonate Rate of reaction When size of calcium carbonate is smaller, the rate of reaction increases

13. Experime nt MVRVHypothesis (MV→RV) To differenti ate between hexene and hexane Hexene and hexane Decolo urised brown bromi ne water When hexene is added to bromine water, brown bromine decolorized, but when hexene is added to bromine water, brown bromine remains unchanged

14. Experime nt MVRVHypothesis (MV→RV) Heat of combusti on of different types of alcohols Types of alcohol s Heat of combu stion When the number of atoms per molecule alcohol increases, the heat of combustion increase

15. Experime nt MVRVHypothesis (MV→RV) Coagulati on of latex Acid and ammo nia solutio n Coagul ation of latex When acid is added to latex, coagulation of latex occurs, but when ammonia solution is added to latex, coagulation of latex does not occur.

16. Now your turn to answer the questions