Operational Definition for spm chemistry

How about "operational definition"? Please remember... It consists of "what to do?" and "what is observed?" and sometimes "the direction".... Example 1: State the operational definition for the hardness of alloy. What to do: 1 kg weight is dropped on steel ball bearing attached to alloy block What is observe: the diameter of dent formed is small Direction: the alloy is harder Suggested answer: When 1 kg weight is dropped on steel ball bearing attached to bronze block, the diameter of dent formed is small shows that the bronze is harder. Example 2: State the operational definition for the rusting of iron. What to do: iron nail is coiled with copper strip placed in hot jelly containing phenolphthalein and potassium hexacyanoferrate(III) What is observe: dark blue spots are formed Direction: the iron rust Suggested answer: When iron nail coiled with copper strip is placed in hot jelly containing phenolphthalein and potassium hexacyanoferrate(III) solution, dark blue spots are formed shows that the iron rust. Example 3: State the operational definition for the end point of titration between acid and alkali. What to do: acid is added slowly into alkali solution mixed with indicator What is observe: the colour of indicator changed Direction: the mixture has neutralised Suggested answer: When hydrochloric acid is added slowly into sodium hydroxide solution mixed with phenolphthalein, the pink solution turns colourless shows that the mixture has neutralised Example 4: State the operational definition for the reactivity of alkali metal when react with water. What to do: alkali metal is placed on the surface of water What is observe: the metal move very rapidly and randomly Direction: the metal is more reactive Suggested answer: When sodium is placed on the surface of water, sodium moves very rapidly and randomly shows that sodium is more reactive metal. Example 5: State the operational definition for the rate of reaction ( factor temperature-reaction of sodium thiosilphate and sulphuruc acid) What to do: heat sodium thiosulphate to the temperature of 50 C and add sulphuric acid What is observe: the time taken for the "X" mark to disappear is short Direction: the rate of reaction is high

Suggested answer: When sodium thiosulphate solution is heated to the temperature of 50 C and sulphuric acid solution is then added, the time taken for the "X" mark to disappear is short shows that the rate of reaction is high.