Thursday, September 16, 2010
Tuesday, August 3, 2010
Monday, July 5, 2010
Chemicals for consumers
Presentation slides :
1) Soaps and Detergents
2) Food additives
3) Medicine
More about :
1) Water surface tension
2) Illustration of surface tension
3) Food emulsifier
4) Emulsifiers in daily life
5) Human homeostasis
1) Soaps and Detergents
2) Food additives
3) Medicine
More about :
1) Water surface tension
2) Illustration of surface tension
3) Food emulsifier
4) Emulsifiers in daily life
5) Human homeostasis
Tuesday, June 29, 2010
Chemicals for consumers
Students tasks :
Groups of 2010
Collect and interpret data of the following topics. You can use the guide to help your search.
(A) Soap and detergent :
1) The history of soap manufacturing
2) What soap and detergent are
3) The preparation of soap and detergent
4) The cleansing action of soap and detergent
5) The differences in the effectiveness of the cleansing action of soap and detergent
6) The additives in detergent
(B) Food additives :
1) Types of food additives
2) Functions of preservatives and antioxidants, flavouring agent, stabilizers and thickening agent, and dyes (azo and triphenyl compounds).
3) The rationale for the use of food additives
4) The effect of food additives on health and the environment
5) Life without food additives
(C) Medicine :
1) Traditional medicines derived from plants and animals : Examples and uses
2) Types of modern medicine
3) Examples and functions of each type of modern medicine : Analgesic, antibiotics, psychotherapeutic medicine
4) The side effects of modern and traditional medicines
5) The correct usage of modern and traditional medicines
Groups of 2010
Collect and interpret data of the following topics. You can use the guide to help your search.
(A) Soap and detergent :
1) The history of soap manufacturing
2) What soap and detergent are
3) The preparation of soap and detergent
4) The cleansing action of soap and detergent
5) The differences in the effectiveness of the cleansing action of soap and detergent
6) The additives in detergent
(B) Food additives :
1) Types of food additives
2) Functions of preservatives and antioxidants, flavouring agent, stabilizers and thickening agent, and dyes (azo and triphenyl compounds).
3) The rationale for the use of food additives
4) The effect of food additives on health and the environment
5) Life without food additives
(C) Medicine :
1) Traditional medicines derived from plants and animals : Examples and uses
2) Types of modern medicine
3) Examples and functions of each type of modern medicine : Analgesic, antibiotics, psychotherapeutic medicine
4) The side effects of modern and traditional medicines
5) The correct usage of modern and traditional medicines
Wednesday, April 7, 2010
Sunday, March 14, 2010
Remember it as it is ! - Form 4 syllabus
1) During heating of a solid substance, why the temperature remains constant?
A : The heat energy absorbed by the particles/molecules is used to overcome the forces of attraction between particles/molecules.
2) During cooling of a liquid substance, why the temperature remains constant?
A : The heat energy released is exactly balanced by the heat loss to the surroundings as the particles/molecules attract one another to form a solid.
3) Proton number = Number of protons in the nucleus of an atom.
4) Nucleon number = Total number of protons and neutrons in the nucleus of an atom.
5) Isotopes = Atoms of the same element with the same number of protons but different number of neutrons.
6) Empirical formula = A chemical formula that gives the simplest whole number ratio of atoms of each element in a compound.
7) Molecular formula = A chemical formula that gives the actual number of atoms of each element in a compound.
8) Why group 18 elements are inert?
A : The atoms have achieved stable electron arrangements.
9) Why group 18 elements exist as monoatomic gases?
A : Atoms of group 18 elements have achieve stable electron arrangements. Their atoms do not donate, accept or share electron with atoms of other elements.
10) Why are group 1 elements have the same chemical properties?
A : The atoms have the same number of valence electron.
11) Why the melting and boiling points of an ionic compound is higher than a covalent compound?
A : An ionic compound consists of oppositely charged ions that are attracted to one another by strong electrostatic force. More heat energy is required to overcome this strong force. Thus, melting and boiling points of an ionic compound is high.
Whereas, a covalent compound is made up of neutral molecules that are held together by a weak intermolecular force of attraction. Therefore, only small amount of heat energy is required to overcome this weak force. The melting and boiling points of a covalent compound is low.
12) Why an ionic compound in aqueous or liquid state can conduct electricity but a covalent compound cannot do so?
A : An aqueous or molten ionic compound has free moving ions, thus it can conduct electricity. But a covalent compound only contains neutral molecules that make it cannot conduct electricity.
13)Why are group 17 elements have the same chemical properties?
A : The atoms have the same number of valence electrons.
14) Strong / weak acid : An acid that ionises completely / partially in water to give high / low concentration of hydrogen ions.
15) Strong / weak alkali : An alkali that ionises completely / partially in water to give high / low concentration of hydroxide ions.
A : The heat energy absorbed by the particles/molecules is used to overcome the forces of attraction between particles/molecules.
2) During cooling of a liquid substance, why the temperature remains constant?
A : The heat energy released is exactly balanced by the heat loss to the surroundings as the particles/molecules attract one another to form a solid.
3) Proton number = Number of protons in the nucleus of an atom.
4) Nucleon number = Total number of protons and neutrons in the nucleus of an atom.
5) Isotopes = Atoms of the same element with the same number of protons but different number of neutrons.
6) Empirical formula = A chemical formula that gives the simplest whole number ratio of atoms of each element in a compound.
7) Molecular formula = A chemical formula that gives the actual number of atoms of each element in a compound.
8) Why group 18 elements are inert?
A : The atoms have achieved stable electron arrangements.
9) Why group 18 elements exist as monoatomic gases?
A : Atoms of group 18 elements have achieve stable electron arrangements. Their atoms do not donate, accept or share electron with atoms of other elements.
10) Why are group 1 elements have the same chemical properties?
A : The atoms have the same number of valence electron.
11) Why the melting and boiling points of an ionic compound is higher than a covalent compound?
A : An ionic compound consists of oppositely charged ions that are attracted to one another by strong electrostatic force. More heat energy is required to overcome this strong force. Thus, melting and boiling points of an ionic compound is high.
Whereas, a covalent compound is made up of neutral molecules that are held together by a weak intermolecular force of attraction. Therefore, only small amount of heat energy is required to overcome this weak force. The melting and boiling points of a covalent compound is low.
12) Why an ionic compound in aqueous or liquid state can conduct electricity but a covalent compound cannot do so?
A : An aqueous or molten ionic compound has free moving ions, thus it can conduct electricity. But a covalent compound only contains neutral molecules that make it cannot conduct electricity.
13)Why are group 17 elements have the same chemical properties?
A : The atoms have the same number of valence electrons.
14) Strong / weak acid : An acid that ionises completely / partially in water to give high / low concentration of hydrogen ions.
15) Strong / weak alkali : An alkali that ionises completely / partially in water to give high / low concentration of hydroxide ions.
Monday, March 8, 2010
Empirical formulae of metal oxides
Experimentally, there are two methods to determine the empirical formulae of metal oxides. The methods depend on the reactivity of the metal.
Method 1 : To determine the empirical formula of oxide of a more reactive metal than hydrogen (in the Reactivity series = metals that are positioned higher than hydrogen in the series).
The principle is that to react the reactive metal with oxygen to produce metal oxide. This is because the metal can react readily with oxygen. In the laboratory, the apparatus set up that is appropriate for the purpose is like the diagram shown below :
In determining empirical formulae of metal oxides, metals that are said to be more reactive than hydrogen include calcium, magnesium, aluminium and zinc.
Taking magnesium as an example, the chemical equation of the reaction is
2Mg + O2 --> 2MgO.
Method 2 : To determine the empirical formula of a less reactive metal than hydrogen (in the Reactivity series = metals that are positioned lower than hydrogen in the series).
For this method, the principle is that to react (reduced) the less reactive metal with hydrogen gas to give its pure metal and water. This method is used because it is more convenient rather than waiting for a slow reaction between the metal and oxygen to react completely.
Below is the apparatus set up used in the laboratory to determine the empirical formulae of oxides of less reactive metals:
These kind of metals include tin, lead and copper. For an example, the reaction between copper(II) oxide and hydrogen is described as follows :
CuO + H2O --> Cu + H2.
Method 1 : To determine the empirical formula of oxide of a more reactive metal than hydrogen (in the Reactivity series = metals that are positioned higher than hydrogen in the series).
The principle is that to react the reactive metal with oxygen to produce metal oxide. This is because the metal can react readily with oxygen. In the laboratory, the apparatus set up that is appropriate for the purpose is like the diagram shown below :
In determining empirical formulae of metal oxides, metals that are said to be more reactive than hydrogen include calcium, magnesium, aluminium and zinc.
Taking magnesium as an example, the chemical equation of the reaction is
2Mg + O2 --> 2MgO.
Method 2 : To determine the empirical formula of a less reactive metal than hydrogen (in the Reactivity series = metals that are positioned lower than hydrogen in the series).
For this method, the principle is that to react (reduced) the less reactive metal with hydrogen gas to give its pure metal and water. This method is used because it is more convenient rather than waiting for a slow reaction between the metal and oxygen to react completely.
Below is the apparatus set up used in the laboratory to determine the empirical formulae of oxides of less reactive metals:
These kind of metals include tin, lead and copper. For an example, the reaction between copper(II) oxide and hydrogen is described as follows :
CuO + H2O --> Cu + H2.
Friday, January 29, 2010
Some good sites
Acidic properties - Reaction with metals :
http://www.gcsescience.com/r4-metal-reaction-with-acid.htm
Writing chemical formulae :
1)http://www.ausetute.com.au/wriiform.html
2)http://www.ausetute.com.au/namiform.html
Naming chemical formulae :
http://www.ausetute.com.au/namiform.html
Polyatomic ions :
http://antoine.frostburg.edu/chem/senese/101/compounds/polyatomic.shtml
Inorganic nomenclature :
1) http://library.thinkquest.org/10429/high/nomen/nomenbody.htm
2)http://www.rose.edu/faculty/vhall/Nomenclature/inorganic_nomenclature.htm
http://www.gcsescience.com/r4-metal-reaction-with-acid.htm
Writing chemical formulae :
1)http://www.ausetute.com.au/wriiform.html
2)http://www.ausetute.com.au/namiform.html
Naming chemical formulae :
http://www.ausetute.com.au/namiform.html
Polyatomic ions :
http://antoine.frostburg.edu/chem/senese/101/compounds/polyatomic.shtml
Inorganic nomenclature :
1) http://library.thinkquest.org/10429/high/nomen/nomenbody.htm
2)http://www.rose.edu/faculty/vhall/Nomenclature/inorganic_nomenclature.htm
Catalytic reactions
The followings are all catalytic reactions in the Chemistry syllabus :
1- To make H2 gas in a small amount in the laboratory :
Zn + H2SO4 => ZnSO4 + H2, catalysts = Copper(II) sulphate, CuSO4
2- Haber process = Manufacture ammonia, NH3 :
N2 + 3H2 => 2NH3, catalyst = Iron, Fe
3- Contact process = Manufacture sulphuric acid, H2SO4 :
SO2 + O2 => SO3, catalyst = Vanadium(V) oxide, V2O5
4- Ostwald process = Manufacture nitric acid, HNO3 :
4NH3 + 5O2 => 4NO + 6H2O, catalyst = Platinum, Pt
5- Decomposition of hydogen peroxide :
2H2O2 => 2H2O + O2, catalyst = Manganese(IV) oxide, MnO2
Catalytic reactions of carbon compounds :
6- Catalytic hydrogenation of alkenes :
C2H4 + H2 => C2H6, catalyst = Nickel, Ni or Pt
7- Hydration of alkenes :
C2H4 + H2O => C2H5OH, catalyst = Phosphoric(V) acid, H3PO4
8- Fermentation = To produce ethanol :
C6H12O6 => 2C2H5OH + 2CO2, catalysts = Zymase from yeast
(Glucose)
9- Dehydration of ethanol :
C2H5OH => C2H4 + H2O
Catalyst = Unglazed porcelian chips, porous pot, pumice stone or Al2O3
10- Esterification reaction = To make esters :
Carboxylic acid + alcohol => ester, catalysts = Concentrated H2SO4
11- Conversion of unsaturated fats into saturated fats = Catalytic hydrogenation, catalyst = Ni
1- To make H2 gas in a small amount in the laboratory :
Zn + H2SO4 => ZnSO4 + H2, catalysts = Copper(II) sulphate, CuSO4
2- Haber process = Manufacture ammonia, NH3 :
N2 + 3H2 => 2NH3, catalyst = Iron, Fe
3- Contact process = Manufacture sulphuric acid, H2SO4 :
SO2 + O2 => SO3, catalyst = Vanadium(V) oxide, V2O5
4- Ostwald process = Manufacture nitric acid, HNO3 :
4NH3 + 5O2 => 4NO + 6H2O, catalyst = Platinum, Pt
5- Decomposition of hydogen peroxide :
2H2O2 => 2H2O + O2, catalyst = Manganese(IV) oxide, MnO2
Catalytic reactions of carbon compounds :
6- Catalytic hydrogenation of alkenes :
C2H4 + H2 => C2H6, catalyst = Nickel, Ni or Pt
7- Hydration of alkenes :
C2H4 + H2O => C2H5OH, catalyst = Phosphoric(V) acid, H3PO4
8- Fermentation = To produce ethanol :
C6H12O6 => 2C2H5OH + 2CO2, catalysts = Zymase from yeast
(Glucose)
9- Dehydration of ethanol :
C2H5OH => C2H4 + H2O
Catalyst = Unglazed porcelian chips, porous pot, pumice stone or Al2O3
10- Esterification reaction = To make esters :
Carboxylic acid + alcohol => ester, catalysts = Concentrated H2SO4
11- Conversion of unsaturated fats into saturated fats = Catalytic hydrogenation, catalyst = Ni
Monday, January 4, 2010
F4 Chapter 1 : Introduction to chemistry
With your partner, you must collect information about chemistry. Below, I've listed down the related subtopics together with some useful links to websites for your guidance. You can browse the suggested links (to save time) or search the subtopics in your preferable search engine, and use any suitable and relevant information to prepare a six-page summary of your research.
In your summary, you must include the followings :
1) The meaning of chemistry / What is chemistry (and why is it important).
2) Choose one common chemical and briefly describe about it and its uses.
3) Choose one chemistry related career and give a brief description about it. You may add any useful information such as the advantages or educational requirements for the occupation.
4) Share your point of view about chemical-based industries in Malaysia and their contributions to the nation.
5) Present and describe scientific method in an interesting and easy to understand diagram or chart.
6) Rationalize the significance of scientific attitudes of chemists or scientists in conducting scientific investigations.
Click links below for extra infromation of the following subtopics :
1) The meaning of chemistry
>> http://chemweb.ucc.ie/what_is_chemistry.htm
>> http://en.wikipedia.org/wiki/Chemistry
>> http://chemistry.about.com/od/generalchemistry/General_Introductory_Chemistry.htm
>> http://chemistry.about.com/od/chemistry101/a/basics.htm
2) Common chemicals and their uses
>> www.chymist.com/Common%20chemicals.pdf
>> http://www.drugs.com/
>> http://www.answers.com/
3)Chemistry related careers
>> http://chemistry.about.com/cs/5/f/blcareers.htm
>> http://www.ehow.com/about_4607263_jobs-related-chemistry.html
>> http://www.ehow.com/facts_5029863_jobs-relate-chemistry.html
>> http://www.ehow.com/about_5286598_job-forensic-chemist.html
>> More links : Chemistry related careers.docx
4) Chemical-based industries and their contributions
>> http://www.mida.gov.my/en_v2/index.php?page=petrochemical
5) Scientific methods
>> http://chemistry.about.com/od/lecturenotesl3/a/sciencemethod.htm
>> http://physics.about.com/od/toolsofthetrade/a/scimethod.htm
>> http://www.sciencebuddies.org/mentoring/project_scientific_method.shtml
>> http://kbagdanov.wordpress.com/2009/04/22/using_the_scientific_method_to_do_science_fair_projects/
>> Some nice charts : Charts of Scientific method.docx
6) Scientific attitudes
>> http://hubpages.com/hub/Scientific-Attitudes-that-are-Qualities-of-Scientists
>> http://wiki.answers.com/Q/What_is_the_%20scientific_attitude_and_what_attitudes_and_characteristics_define_a_good_scientist
In your summary, you must include the followings :
1) The meaning of chemistry / What is chemistry (and why is it important).
2) Choose one common chemical and briefly describe about it and its uses.
3) Choose one chemistry related career and give a brief description about it. You may add any useful information such as the advantages or educational requirements for the occupation.
4) Share your point of view about chemical-based industries in Malaysia and their contributions to the nation.
5) Present and describe scientific method in an interesting and easy to understand diagram or chart.
6) Rationalize the significance of scientific attitudes of chemists or scientists in conducting scientific investigations.
Click links below for extra infromation of the following subtopics :
1) The meaning of chemistry
>> http://chemweb.ucc.ie/what_is_chemistry.htm
>> http://en.wikipedia.org/wiki/Chemistry
>> http://chemistry.about.com/od/generalchemistry/General_Introductory_Chemistry.htm
>> http://chemistry.about.com/od/chemistry101/a/basics.htm
2) Common chemicals and their uses
>> www.chymist.com/Common%20chemicals.pdf
>> http://www.drugs.com/
>> http://www.answers.com/
3)Chemistry related careers
>> http://chemistry.about.com/cs/5/f/blcareers.htm
>> http://www.ehow.com/about_4607263_jobs-related-chemistry.html
>> http://www.ehow.com/facts_5029863_jobs-relate-chemistry.html
>> http://www.ehow.com/about_5286598_job-forensic-chemist.html
>> More links : Chemistry related careers.docx
4) Chemical-based industries and their contributions
>> http://www.mida.gov.my/en_v2/index.php?page=petrochemical
5) Scientific methods
>> http://chemistry.about.com/od/lecturenotesl3/a/sciencemethod.htm
>> http://physics.about.com/od/toolsofthetrade/a/scimethod.htm
>> http://www.sciencebuddies.org/mentoring/project_scientific_method.shtml
>> http://kbagdanov.wordpress.com/2009/04/22/using_the_scientific_method_to_do_science_fair_projects/
>> Some nice charts : Charts of Scientific method.docx
6) Scientific attitudes
>> http://hubpages.com/hub/Scientific-Attitudes-that-are-Qualities-of-Scientists
>> http://wiki.answers.com/Q/What_is_the_%20scientific_attitude_and_what_attitudes_and_characteristics_define_a_good_scientist
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