Determing Melting Point

Example of Essay Question:
Solid Z has a melting point of 65^oC.  Describe a laboratory experiment to determine the melting point of Z. Your answer should show how the melting point of Z is determined.

Requirement of the Question 

a) Procedure and diagram
b) A table showing time and temperature.
c) Sketch a graph temperature of substance Z against time.
d) Show how melting point of substance can be obtained from the graph.

Cave of Giant Crystals, Mexico

The crystals in the cave are made of selenite, a form of the common mineral gysum.  Slelenite is translucent & soft.  Research carried out by the scientist through uranium-thorium dating suggests the larget crystals are about 600 000 years old.

For more details, visit http://www.crystalinks.com/mexicocrystals.html

Question Analsysis Paper 2 Section B & C Trial Chemistry SPM 2010 from All the States

This is quoted from Mr Yeoh blog http://spmchem.blogspot.com/ for your reference.

Perfect Score Chemistry Module Year 2010

Perfect Score Chemistry Year 2010 compiles common questions for Paper 2 & 3 SPM into 4 set. 

Set 1: Chapter 2, 3, 4, & 5 in Form 4
Set 2: Chapter 6 in Form 4 & Chapter 3 in Form 5
Set 3: Chapter 7 & 8 in Form 4; Chapter 1 & 4 in Form 5
Set 4 : Chapter 2 & 5 in Form 5, Chapter 9 in Form 4

To download,

• Question
• Answer Scheme

This set is helpful especially to know better common questions in Paper 2 & 3 SPM.

Trial SPM Wilayah Persekutuan Chemistry Paper 3 2010

Yesterday, my students sat for the exam. There are only two questions.

1. Determining heat of displacement of copper by different metals.
2. Planning an experiment to determine the position of carbon based on it ability to reduce metal oxies.

The first question were somehow the same like one of the past year question(heat of neutralisation).  My both classses did carry out this experiment. But I wonder whether they can answer the question with high score. Best of luck to all of them which is going to sit for Chemistry Trial SPM Paper 1 & Paper 2 tomorrow!

Question Analysis Chemistry Trial SPM Paper 3 2010 from Different States

States	Question 1	Question 2	Question 3
SBP	Reactivity of alkali metals towards oxygen	Effect of metals on iron rusting	Effect of size of zinc on the rate of reaction
Terengganu	Heat of combustion of various alcohols	Reactivity of alkali metals towards oxygen	Effect of catalyst on the rate of decomposition of hydrogen peroxide
Kedah	Reactivity of alkali metals with oxygen	Effect of quantity of catalyst on the rate of decomposition of hydrogen peroxide	Effect of metals on the rusting of iron
Penang	Electrical conductivity of lead(II) bromide & naphthalene in molten state	Effect of the amount of catalyst on the rate of reaction	Investigate the effect of ethanoic acid & ammonia solution on the coagulation of latex
Negeri Sembilan	Construct the electrochemical series based on voltmeter reading by using different metals pair with copper	Determine the concentration of potassium hydroxide by using titration method	Investigate the electrical conductivity of lead(II) bromide & naphthalene
Sabah	Compare heat of combustion of alcohols	Reactivity of halogens with iron wool	Investigate the effect of metals on iron rusting
Perak	End-point of titration	-	Effect of temperature on the rate of reaction
MRSM	Construct ionic equation for the precipitation of silver chloride	-	The effect of other metals on rusting of iron
Johor	Effect of other metals on rusting of iron	-	Effect of catalyst on the rate of reaction
Perlis	Construct electrochemical series based on the potential difference of pairs of metals	-	Effect of concentration/catalyst on the rate of reaction between an acid & metal
Kelantan	Heat of combustion of various alcohols	-	Effect of the type of electrode on the product of electrolysis at anode
Kuala Lumpur	Heat of displacement of copper by different metals	-	determine the position of carbon in the reactivity series based on its ability to reduce metal oxides
Pahang	Heat of combustion of alchols	-	Effect of catalyst on the rate of decomposition of hydrogen peroxide
Mallaca	Relationship between concentration of nitric acid and its pH value	-	Investigate the difference in electrical conductivity between an ionic compound and a covalent compound
Selangor	Effect of metal on rusting of iron	-	Effect of temperature on the rate of reaction

Trial Chemistry SPM 2010 from Different State

Please visit http://chngtuition.blogspot.com/2010/09/2010-spm-all-chemistry-state-trial-exam.html
to download Trial Chemistry SPM from

1. Johor
2. Perak
3. Kedah
4. Terengganu
5. Perlis
6. Kelantan
7. Pahang
8. Melaka
9. Penang
10. Negeri Sembiln
11. Selangor
12. Sabah
13. Penang
14. Selangor
15. MRSM
16. Kuala Lumpur

chem2u will update from time to time once chem2u find questions from other states too.

Chemistry Form 4 Finals Mallaca 2009

You may look at this set of question how the real format of  Paper 1, 2 & 3 looks like while preparing for the coming finals.

All the best, any doubts of the question, do leave a comment here. I''ll help to clarify the concepts.

Download

Chemistry Trial SBP 2010

Paper 1

Paper 2

Paper 3

Answer Scheme

If you feel this link is good for your friends, do share with them.

Chemistry SPM Paper 3 Question Analysis from 2003 – 2009

Year	Structure Question	Planning an Experiment
2009	1 Effect of type of electrode on the electrolysis of aqueous solution 2 Rate of reaction	1 Relationship between concentration of nitric acid & pH value
2008	1 Effect of ethanoic acid and ammonia solution on the coaagulation of latex	1 Reactivity of lithium, sodium and potassium with water
2007	1 Exothermic & endothermic reaction	1 Construct electrochemical series to determine factor that influence the difference in voltage
2006	1 Heat of neutralization	1 Compare iron & steel from the aspect of hardness/resistant to corrosion
2005	1 Freezing point of naphthalene 2 Electrochemical series based on potential difference	1 Effect of alloying on the hardness of metal 2 How concentration affect the rate of reaction of acid with metal
2004	1 Empirical formula of magnesium oxide 2 Reactivity series of metals	1 Prepare esters from two different alcohol
2003	1 Effect of temperature on the rate of reaction 2 Construct ionic equations through continuous variation method	1 Compare the elasticity of vulcanized rubber & unvulcanized rubber

SPM 2007 Paper 3 Question 2 - Chemical Cells

Please attempt the question first. If you have any querry, don't hesitate to email me. 

Suggested answer, please click here.

Preparation of Soluble Salt - Copper(II) Sulphate

The photo shows copper(II) sulphate prepared by one group of students in my chemistry class.
Copper(II) sulphate can be prepared by using one of the reactions

1. sulphuric acid and copper(II) oxide
2. sulphuric acid and copper(II) carbonate

Chemical equation for the first equation:

1. H₂SO₄ + CuO  --> CuSO₄ + H₂O
2. H₂SO₄ + CuCO₃  --> CuSO₄ + H₂O

The slide follows briefly shows the steps taken. The copper(II) oxide can be replaced by copper(II) carbonate too.



In SPM 2003, students are required to describe a laboratory experiment to prepare dry magnesium chloride based on given materials :

• magnesium sulphate solutions,
• dilute hydrochloric acid,
• potassium carbonate solution

 This question is a bit tricky. Students need to consider few things before write their plan:

1. Is magnesium chloride a soluble salt?
2. What are reactants used to prepare magnesium chloride?
3. Are the reactants required given in the list?
4. How to make use of the given materials?(Hint: precipitation reaction)
5. Explain the procedure in details.

Need any further guide, just write in the comment!

Krypton Bulb

krypton bulb

Krypton like other argon gases is used in lighting.  Krypton bulb usually emits bright white light.

How Factors Affecting the Rate of Reaction are Applied in Industrial Processes

Questions about the topic is frequently found in Paper 1 SPM. Students are given various choices of condition of reaction but students hardly to pick a correct answer. Normally when I teach rate of reaction, I ask my students to collect all related information and complete the table. They can revise it anytimes  especially last-minute revision.

Sometimes, this topic is asked in Paper 2 too. Students are asked to state the temperature, pressure & catalyst in a reaction and explain how does each factor affecting the rate of reaction by using collision theory.

Formation of Ionic Bond & Covalent Bond

Formation of chemical bond is one of the important concepts in chemistry. In Chemistry SPM, students are introduced ionic bond and covalent bond in when they were in form 4.

The following video shows the formation of ionic bond by using formation of sodium chloride as an example.
Ionic bond is the strong electrostatic force of attraction that holds the oppositely charged ions.

The following show samples of answer when explaining formation of ionic bond in essay Chemistry SPM.

• Electron arrangement of sodium atom is 2.8.1
• A sodium atom donates one electron to achieve stable octet electron arrangement
• A sodium ion, Na⁺ is formed
• This electron is transferred to a chlorine atom with an electron arrangement of 2.8.7
• A chlorine atom accepts electron from sodium atom to achieve the stable octet electron arrangement
• Chloride ion, Cl^-, is formed
• The sodium ion, and chloride ion, are attracted to one another by a strong electrostatic force/ionic bond to form an ionic compound, sodium chloride, NaCl.

The following video show formation of covalent bond. 
A bond that is formed when a pair of valence electrons are shared between two non-metal atoms.

There are three type of of covalent bond :

• single bond
• double bond
• triple bond

SPM Corner:
Electron arrangement for atom W : 2. 4
Electron arrangement for atom X : 2.8.7
Electron arrangemnt for atom Y : 2.8.8.2

Based on the given information, explain how two compounds can be formed from these elements based on their electron arrangements.

The two compounds should have different bond types. [10 marks]
[2005]

Guide:
Formation of Ionic Bond:

• State the electron arrangement of both atoms.
• Explain how each atom achieve stable electron arrangement. E.g. To achieve stable electrons arrangement, atom Y donates 2 electrons to form Y²⁺ ion while atom X donate 1 electron to form X⁺ ion 
• Explain the ions formed are attracted by strong electrostatic force.
• Give the formula of the compound formed.
• Draw the electron arrangement of the compound formed.

Formation of Covalent Bond:

• State the electron arrangemnt of and the number of valence electrons of each atoms.
• Explain how many more electrons for each atom to achieve stable electron arrangement. E.g. Atom W need 4 electrons to achieve stable electron arrangement while atom Y needs 1 electron to achieve stable electron arrangement 
• Explain how do the atoms share electrons. E.g. Atom W contributes 4 electrons for sharing while atom X contribute 1 electrons for sharing.  Each four Y atoms share 1 pair of electrons with one W atoms
• State the formula of the compound formed.
• Draw the electron arrangment of the compoud formed.