Tips Edited by Mr. Chai and Yati 2016 PDF
Tips Edited by Mr. Chai and Yati 2016 PDF
Tips Edited by Mr. Chai and Yati 2016 PDF
1)Explain the diffusion of bromine particles throughout the two gas jar.
- Bromine gas consist of tiny and discrete particles.
- When cover is removed, the bromine molecules move randomly from higher concentration region to lower
concentration region
Stoichiometric calculation
Step 1:
Convert a given quantity (mass / volume ; given molarity& volume) into number of moles.
Step 2:
Write a balanced equation
Step 3:
Based on the mole ratio, determine the number of moles of the unknown quantity.
Step 4:
Convert the calculated number of moles into required quantity ( mass ; volume; molarity ).
3. Describe an experiment to determine empirical formula of magnesium oxide – Not in Essay section before!
- Include a labelled diagram
- procedures
- Data
- Show the calculation in table form to determine the empirical formula of magnesium oxide
4. Experiment to determine the melting point of substance X (Only Asked once in SPM 1997)
Substance X
Practice all the balanced chemical equations for all the reactions in group 1 and group17
Group 1 + water Group 17 + water
2Na + 2H2O 2 NaOH + H2 Cl2 + H2O HCl + HOCl
Group 1 + oxygen Group 17 + NaOH
4Li + O2 2Li2O Cl2 + 2NaOH NaCl + NaOCl + H2O
Group 1 + halogen Group 17 + iron
2K + 2Cl2 2 KCl 3Cl2 + 2Fe 2 FeCl3
Must able to explain the difference reactivity of elements when going down the group 1 and 17
COMPARE THE REACTIVITY OF SODIUM AND POTASSIUM
• Atomic size of potassium atom is bigger than sodium atom
• Distance between nucleus and valence electron of potassium atom is further than sodium atom
• The forces of attraction between nucleus and valence electron of potassium atom is weaker than
sodium atom
• Potassium atom is easier to release its valence electron than sodium atom
• Hence potassium atom is more reactive than sodium atom
Explain the formation of ionic bond and covalent bond + draw the electron arrangement
FORMATION OF MAGNESIUM CHLORIDE FORMATION OF CARBON DIOXIDE
Pt1: The electron arrangement of Magnesium atom is 2.8.2 Pt1 : Electron arrangement of atom D is 2.4.
Pt2 : The electron arrangement of chlorine atom is 2.8.7 Pt2 : Electron arrangement of atom E is 2.6.
Pt3 : In order to achieve a stable octet electron arrangement Pt3 : In order to achieve a stable octet electron arrangement,
Pt4 : A Magnesium atom donates 2 electrons to form a Pt4 : An atom D contribute 4 electrons for sharing
positive ion , Mg2+ . Pt5 : Each of two atom E contribute 2 electrons for sharing
Pt5 : Each of the two chlorine atom receives 1 electron to Pt6 : Atom D share electrons with 2 atoms E to form
form negative ion , Cl- . covalent bond
Pt6 : Mg2+ and Cl- are attracted together by strong Pt7 : Covalent compound, DE2 is formed.
electrostatic force Pt 8 & Pt 9 :
Pt7 : to form an ionic compound, MgCl2
Pt8 & Pt9 :
Explain the differences of physical property of ionic compound and covalent compoundfrom aspect electrical condu
ctivity and the melting point
Ionic compound ions Covalent compound -molecules
HIGH MELTING AND BOILING POINT LOW MELTING AND BOILING POINT
-The ions are attracted together by strong electrostatic -The molecules are attracted together by weak Van Der
force Waals force
-More heat energy is required to overcome the forces of -Less heat energy is required to overcome the forces of
attraction between the ions attraction between the molecules
CAN CONDUCT ELECTRICITY IN MOLTEN OR CANNOT CONDUCT ELECTRICITY IN ANY STATE
AQUEOUS STATE - consists only neutral molecules
-the ions can move freely - No freely moving ions are present
Compound M N
Observation The white solid remains The white solid N dissolves
unchanged in the water. and a colourless solution is
formed.
Table 9
The student carried out another experiment to study the electrical conductivity of compounds M and N in the solid
and molten states.
By using a suitable examples of compound M an compound N, describe an experiment how you can differentiate
compound M and compound N based on their electrical conductivity in the solid and molten states. [10 marks]
Pt1 : Compound M : _____________________________________________________________________
Pt2 : Compund N : ________________________________________________________________________
[reject : polyatomic ion, eg : sodium sulphate / sodium hydroxide]
Pt3 - pt8 : Writing the procedures to conduct the experiment .
Describe an experiment to prove chemical energy can be converted into electrical energy
V
Pt1 & Pt2 : Draw a labelled diagram for the set-up of apparatus
Pt 3 - Pt6 : Describe the procedures for conducting the experiment
Pt7 & pt8 : Observation : 1. Voltmeter shows reading
2. Observation at the positive and negative terminal
Pt9 & Pt10 : Half equation at the positive terminal and negative terminal
Displacement reaction
The arrangement of four metals in decreasing order of their electropositivity is shown below.
W, X, Y, Z
Decreasing order of electropositivity
You are provided with strips of metals W, X, Y and Z and nitrate solution of W, X, Y and Z respectively.
Describe an experiment to verify the arrangement of these metals.
Pt1 - Pt5 : Able to describe the procedures for conducting the experiment.
Pt6 : Tabulation of the result
Pt7 - pt9 : Interpreting data - Describe how the arrangement is derived from the result
Pt10 : Conclusion
Based on the above situation, plan a laboratory experiment to electroplate an iron spoon with silver metal and copper metal
using the electrolysis process.
You are given silver nitrate solution and copper (II) nitrate solution.
Your planning must include the following items:
(a) Problem statement
(b) All the variables
(c) Statement of the hypothesis
(d) List of materials and apparatus
(e) Procedure of the experiment
(f) Tabulation of data
Able to compare and contrast chemical cell and electrolytic cell (essay part)
Copper Zinc
Copper Zink
Kuprum Kuprum
Diagram 8.2
Type of cell
The energy change
Ions presence in the electrolyte
The anode and cathode of the cells
Half equations for both electrodes
Observation at the anode of each cell [10 marks/markah]
Cell A Cell B
Sel A Sel B
Type of cell Electrolytic cell Voltaic cell / Chemical cel
Energy change Electrical energy to chemical energy Chemical energy to electrical energy
Ions presence in
the electrolyte Cu2+, H+, SO42-and OH-
13.Planning experiment paper 3 : Effect of Type of position of ions in the electrochemical series /
type of electrode / effect of concentration of electrolyte
[Refer to the planning experiment]
Form 4 Chapter 7 (Acid and Bases & Form 4 Chapter 8 (SALTS) Spot in structure!!
[2015 : Essay section B : Different pH value between strong acid and weak acid + titration + electrical conductivity and
acidic property of hydrogen chloride in solvent X and solvent Y]
[2015 : Essay Section C : Preparation of soluble salt and insoluble salt in the laboratory]
a) able to define the meaning of salt
[Common mistake by students : Chemical compound formed from the neutralisation between acid and base]
c) Able to describe a chemical test to identify all the anion (CO32-, Cl-, SO42-, and NO3-)
(Use RODA IMPIAN To memorize all the chemical reagents)
Haber Process
a) Able to state conditions required to produce higher percentage of ammonia
b) Able to write a balanced chemical equation for the reaction occured in Haber Process
Ammonium Sulphate is the product formed by Contact Process and Haber Process.
a) Able to state the use of ammonium sulphate
b) Able to calculate the percentage of nitrogen by mass of given fertilizers and able to choose the best fertilizer.
Alloy + Glass + Ceramic + Polymer + Composite materials - structure / essay
a) Able to explain the difference in the hardness of pure copper and bronze
b) Able to state the specific properties of the use of alloy/glass/ polymers/composite materials
Examples 2 :
Marble reacts with dilute acid to liberate carbon dioxide gas.
By using one of the acid in 10 (a) (i), describe how to carry out an experiment to determine the rate of liberation of
carbon dioxide gas at 60 seconds.
Your answer should include the method to calculate the rate of reaction at 60 seconds.
Pt1 - Pt6 : Able to describe procedures to conduct the experiment.
Pt7 : Tabulation of data
Pt8 : Able to sketch a graph of volume of gas against time + Titles of axis with unit
Pt9 : Able to draw tangent (line AB) at 60 seconds
Pt 10 : Able to calculate the gradient of the tangent AB
Volume of CO2
V1
V2
t1 60 t2
PAPER 3
MASTER 12 SCIENCE PROCESS SKILLS
Reactivity of group 1 element with oxygen gas: What is the operational definition for the reactivity of
group 1 element with oxygen gas?
ANSWER : The brighter the flame produced when alkali metals burns in oxygen gas, the more reactive the
metal is.
Reactivity of group 17 elements with hot iron wool : What is the operational definition for the reactivity
of group 17 elements with hot iron wool?
ANSWER : Iron wool ignites with a brighter flame shows halogen is a more reactive when halogen gas is
passed over hot iron wool.
Displacement of metal // Displacement of halogen: What is the operational definition of displacement
of metal?
ANSWER : Change of colour in the solution or deposition of solid metal in the solution shows displacement
of metal occurs when[ more electropositive metal] is added into the [solution contain less electropositive
metal ion].
Hardness between alloy and pure metal : what is the operation definition for the hardness of the
materials?
ANSWER : The smaller diameter of dent created when 1 kg weight is dropped into a steel ball bearing that
taped on the metal block, the material is harder.
Effectiveness of the cleansing action of soap and detergent in hard water : What is the operational
definition of the effectiveness of the cleaning agent?
ANSWER : Cleaning agent which can remove the oily stains on the cloth/ does not form scum when the
cleaning agent is added into hard water indicates that the cleaning agent is more effective.
(Planning Experiment)
Asked in the previous year :
Form 4 : To construct ES based on potential difference // experiment to compare hardness of alloy and pure
metal // reactivity of group 1 elements with water // Experiment continuous variation method // To study
affect of different concentration of acid on pH value // To study the role of water in showing the property of an
alkali // Solubility of sulphate salt in water
Form 5 : Elasticity of vulcanized and unvulcanised rubber // Esterification // effect of concentration of acid on
rate of reaction // Effect of catalyst on r.o.r between metal and acid //To differentiate hydrocarbon X (hexane)
and hydrocarbon Y(hexene) // To study the effect of more electropositive metal and less electropositive metal
on rusting
Form 4
1. To study the acid and base properties of aluminium oxide, sodium oxide and phosphorus pentoxide
2. Experiment to construct ES based on displacement of metals
3. To study the factor of position ions/concentration ions/type of electrode on the products of electrolysis
// Electroplating of metal
4. To compare the rate of rusting between iron, steel and stainless steel
Form 5
1. Experiment to identify exothermic and endothermic for the reaction between solid sodium hydroxide in
water and reaction between ammonium chloride in water.
2. Experiment to compare the heat of neutralisation between strong acid and weak acid with strong alkali.
3. Heat of Combustion
4. Experiment to study the factor of concentration / temperature of sodium thiosulphate on r.o.r
5. Experiment to study the effect of amount of catalyst on the rate of decomposition of hydrogen peroxide
6. Experiment to study the effectiveness of soap and detergent in hard water
THE END