Folio Chemistry

1 | H a k C i p t a T e r p e l i h a r a M J S C K u b a n g P a s u

MARA JUNIOR SCIENCE COLLEGE

OF

KUBANG PASU

NAME : MOHAMAD RIZWAN BIN ABDUL RASID

CLASS : 506 FORTUNATE

MATRIX NO. : 09708

SUBJECT TEACHER’S : PN. FAZILAH BT HAMZAH

CHEMISTRY : CHEMICAL FOR CONSUMERS

Title Page SOAP AND

DETERGENT3 - 15

FOOD ADDITIVES 16 - 23MEDICINE 24 - 32


SOAP & DETERGENT

SOAPS

- Cleansing agents are chemical substances used to remove grease and dirt.- There are two types of cleansing agents:

a) Soapsb) Detergents

History of soap manufacturing


- Have been used for more than 3000 years. It was recorded that the Babylonians were making soap around 2800 B.C.

- In ancient times, soaps were made from ashes of plants which contain sodium carbonate and potassium carbonate. The ashes were boiled with lime (calcium oxide) to produce caustic potash (potassium hydroxide). Caustic potash is then boiled with animal fats to produce soap.a) Ash + lime ͢boil caustic potash

(K2CO3) (CaO) (KOH) b) Caustic potash + animal fats ͢boil soap

- In 1816, the French chemist Michel Chevreul (1786 – 1889) discovered that animal fats are composed of fatty acids and glycerol. This discovery contributed to the rapid development of the soap and candle industry.

- In 1861, the Belgian chemist Ernest Solvay (1838 – 1922) discovered the process to make soda (sodium carbonate) from common salt (sodium chloride) and calcium carbonate. This process is known as the Solvay Process which produces sodium carbonate which is used to making glasses, soaps and detergents.

Preparation of Soap by Saponification

- Soap are sodium or potassium salts of long chain carboxylic acids with 12 to 18 carbon atoms per molecule. The general formula of a soap is RCOO-Na+ or RCOO-K+.

- Example of soap :

Fatty acid Example of soapC15H31COOHPalmitic acid

C15H31COO-Na+

Sodium palminateC17H33COOHOleic acid

C17H33COO-K+

Potassium oleateC17H35COOHStearic acid

C17H35COO-K+

Potassium stearate

- Soap is produced by the reaction between sodium hydroxide or potassium hydroxide with animal fats or vegetable oils. This reaction is known as saponification.

- Fats and vegetable oils are large, naturally occurring ester molecules. When fats or oils are boiled with concentrated alkalis, such as sodium hydroxide or potassium hydroxide, saponification occurs and ester molecules are broken down into soap and glycerol.

+


Fats and oils(natural ester)

NaOH (aq) or KOH (aq) (alkali)

+

- Saponification is alkaline hydrolysis of ester using alkali solutions. From a chemical aspect, soap is sodium salts or potassium salts of long chain fatty acids (with 12 to 18 carbon atoms per molecule).

- Glyceryl tristearates are naturally occurring ester commonly found in animal fats and vegetable oils. When the ester is boiled with concentrated sodium hydroxide solution, saponification (alkaline hydrolysis) occurs and a mixture sodium stearate (soap) and glycerol is obtained.

CH2COOC17H35 CH2OH

CHCOOC17H35 + 3NaOH (aq) saponification

CHOH + 3C17H35COO- Na+

boil soapCH2COOC17H35 CH2OH (sodium stearate)Glyceryl tristearate (in fats and oils) Glycerol

- The soap produced can be precipitated by adding common salt (sodium chloride) to the reaction mixture. Sodium chloride reduces the solubility of the soap in aqueous solution and causes the soap to be precipitated out.

- The properties of soap depend on :a) The type of alkali used for saponification.b) The type of animal fats or vegetables oils used.

- Soaps produced from sodium hydroxide are hard whereas soaps produced from potassium hydroxide are soft.

- Animal fats (tallow) from cow and vegetable oils (such as palm oils and olive oils) are used for making soap.The structure of soap molecule

- When soap is dissolved in water, it will dissociate and produce sodium ions and carboxylate ions (RCOO-). For example, sodium stearate (soap) dissolves in water to form sodium ions and stearate ions.

C17H35COONa (s) + H2O C17H35COO- (aq) + Na+ (aq)Sodium stearate Water Stearate ions Sodium ions


Glycerol (an alcohol with three –OH groups)

Soap (RCOONa or RCOOK)

- The stearate ions take part in the removal of dirt but the sodium ions do not. The stearate ion consists of two parts: the ‘head’ and the ‘tail’. The ‘head’ is negatively-charged and the ‘tail’ is a long hydrocarbon chain.

O ║

- The ‘head’ contains the – C – O – ion which dissolves in water (hydrophilic) but does not dissolve in oil. Conversely, the ‘tail’ contains a long hydrocarbon chain which is insoluble in water (hydrophobic) but dissolves readily in oil.

- Soaps made from palmitic acid are known as sodium palmitate. Figure 5.2 shows the structure of the palmitate ion (C15H31COO-) in soap. O

║ CH2 CH2 CH2 CH2 CH2 CH2 CH2 – C – O-

CH3 CH2 CH2 CH2 CH2 CH2 CH2 CH2 the ‘tail’ is negatively-charged

and is hydrophilic in nature.

The ‘tail’ of a long hydrocarbon chain which is hydrophobic in nature

Figure 5.2: The structure of palmitate ion

- Figure 5.3 (a) shows the molecular model of palmitate ion and Figure 5.3 (b) shows the simple representation of the structure of the palmitate ion.

hydrophilic ‘head’

hydrophobic ‘tail’

(a) The molecular model of palmitate ion (b) The diagrammatic representation of the soap ion Figure 5.3: The palmitate ion

DETERGENTS

- Detergent are synthetic cleansing agents made from hydrocarbon obtained from petroleum fractions. Thus, detergents are petrochemicals.

- Detergents can be classified into three main types, depending on the charge on the detergent ion.a) Anionic detergents where the head of the detergent particle contain a negatively-

charged ion.


Example: R – O – SO3- Na+ (negatively-charged ion)

b) Cationic detergents where the head of the detergent particle contains a positively-charged ion.Example: R – N(CH3)3

+ Br- (positively-charged ion)c) Non-ionic detergents

Example: R – O – CH2CH2OH

Preparation of detergent

- The detergent, sodium alkyl sulphate can be prepared from alcohols with chain length of 12 to 18 carbon atoms in two steps.

Step 1: Reaction with concentrated sulphuric acid

O O ║ ║

R – O – H + H – O – S – O – H R – O – S – O – H + H2O ║ ║ O O

Long chain alcohol concentrated sulphuric acid alkyl hydrogen sulphate

Step 2: Neutralisation with sodium hydroxide solution

O O ║ ║ R – O – S – O – H + NaOH R – O – S – O- Na+ + H2O ║ ║

O Oalkyl hydrogen sulphate sodium alkyl sulphate

- An example of long chain alcohol is laundry alcohol (dodecan-1-ol), CH3(CH2)10OH. The detergent prepared from dodecan-1-ol is called sodium dodecyl sulphate (IUPAC name) or sodium laundry sulphate (common name), CH3 (CH2)10CH2O-SO3

- Na+.- The equation for the preparation of sodium laundry sulphate is shown below:

Step 1: Preparation of laundry hydrogen sulphateCH3 (CH2)10CH2OH + H2SO4 CH3 (CH2)10CH2OSO3H + H2O Laundry alcohol Laundry hydrogen sulphate

Step 2: Preparation of sodium laundry sulphate


CH3 (CH2)10CH2OSO3H + NaOH CH3 (CH2)10CH2OSO3- Na+ + H2O

Laundry hydrogen sulphate Sodium laundry sulphate

- Sodium alkyl benzene sulphinate, were first used in 1940s. It can be prepared in three steps. The starting materials for making this detergents in a long chain alkene, RCH = CH2, obtained from the cracking of petroleum.

a) Step 1 : Alkylation

Alkylation is the introduction of the alkyl group to an organic molecule.

b) Step 2 : SulphonationAlkylbenzene produced the react with concentrated sulphuric acid to form alkylbenzene sulphonic acid.

Sulphonation is the introduction of the sulphonic acid group, -SO3H to an organic molecule to form sulphonic acid.

c) Step 3 : Neutralisation

Alkylbenzene sulphonic acid produced is the reacted with sodium hydroxide to form sodium alkylbenzene sulphonate, the detergent


RCH = CH2 +

R – alke

nebenzene

alkylbenzenewhere R is along-

chain hydrocarbon

R –

R –

R – + HO – SO3Halkylbe

nzene

– SO3H + H2OAlkylbenzene

sulphonic acid(H2SO4)

The structure of detergent molecule

When a detergent is dissolved in water, it dissociates to form sodium ions and detergent ions. The detergent ions have the same basic structure as the soap ions, that is, it consists of two parts:a) The ‘head’ is the sulphate group ( - OSO3 -) which is negatively-charged and

hydrophilic (dissolves readily in water but not in oil and grease).b) The ‘tail’ is the long hydrocarbon chain, which is neutral and hydrophobic (dissolves

readily in oils and grease but not in water).

hydrophilic ‘head’

OSO3-

ionic ‘head’ (hydrophilic)

hydrocarbon ‘tail’ (hydrophobic)

Alkyl sulphate ion

S03-

hydrocarbon ‘tail’ (hydrophobic)

ionic ‘head’ (hydrophilic)

Alkylbenzene sulphonate ionThe cleansing action of soap and detergent

The cleansing action of soap or detergent depend o their chemical bonding and structures.


R –

R –

– SO3H + NaOH

– SO3 -

Na +Sodium alkylbenzene sulphonate (detergent)

+ H2

O

a) The ionic ‘head’ (negatively-charged) is soluble in water (hydrophilic) but insoluble in oil.b) The long hydrocarbon ‘tail’ (neutral) is insoluble in water (hydrophobic) but soluble in

oil.


STEP 1: ACTION OF DETERGENT ON DIRT

When soap or detergent is mixed with water it lowers the surface tension of water and wets the dirty surface.

The negatively-charged ‘heads’ of soap or detergent ions dissolve in water (hydrophilic).

The hydrocarbon ‘tails’ of soap or detergent ions dissolve in the layer of grease (hydrophobic).

STEP 2: DIRT BEING SURROUNDED BY SOAP OR DETERGENT IONS

If the water is agitated slightly, the grease begins to lift off the surface.

Additives in detergents

- Modern detergent used for washing clothes usually contain a few types of additives to


STEP 3: LIFTING DIRT FROM CLOTH

On further agitation during washing, the greasy dirt is lifted from the surface since the density of the grease is less than water.

STEP 4: EMULSIFYING DIRT IN WATER

When the water is shaken, the grease will be emulsified when it breaks into smaller droplets.

These greasy droplets repel one another because they carry the same charge. As a result, the grease is suspended in the solution.

When the cloth is rinsed with water, the droplets will be carried away.

a) Increase their cleaning power.b) Make them attractive and saleable.

- Only about 20% of the substances in a detergent are cleansing agents (sodium alkyl sulphate or sodium alkylbenzene sulphonate). The other substances are additives. The examples of addictives and their functions are described as follows :

Builders: Sodium tripolyphosphate (Na5P3O10)

a) Sodium tripolyphospathe is used to soften hard water. In the presence of sodium tripolyphosphate, Ca2+

ions and Mg2+ ions are removed.b) Sodium tripolyphosphate increases the pH value of water. In this way, muddy

dirt can be removed.

Whitening / bleaching agents: sodium perborate

a) Bleaches (bleaching agents) remove coloured stains by oxidation process. When coloured stains are oxidized, the colour will disappear.

b) The whitening (bleaching) agents commonly use in detergent is sodium perborate (NaH2BO43H2O). Sodium perborate decomposes in hot water to release oxygen (an oxidising agent) which is responsible for the whitening (bleaching) action.

c) Unlike chlorine, oxygen does not bleach the colour of dyes are not damaging to fabrics. When properly used, the perborate bleaches make fabrics whiter than chlorine bleaches and the colorful dyes of the fabrics do not fade when dirty stains are removed.

d) Besides sodium perborate, sodium hypochlorite, (NaCIO) can also be used as bleaches in detergents. The IUPAC name of sodium hypochlorite is sodium chlorate (I).

e) Sodium hypochlorite releases chlorine that bleaches with dirty stains. However, high concentrations of chlorine can be quite damaging to fabrics. These bleaches do not work well on synthetic fabrics (polyster fabrics), often causing a yellowing rather than the desire whitening. Also chlorine causes the dyes on fabrics to fade.

Biological enzymes: Amylase, lipase, and protease


a) Protein stains such blood, milk, and tomato sauce cannot be removed by the ordinary detergents because these types of stains are insoluble in water.

b) Biological enzymes in detergents can break down fat and protein molecules in food stains. The fatty acids, glycerol and amino acids produced are soluble in water and are removed during washing.

Brighteners

a) Figure below shows the action of brighteners. The brighteners absorb the invisible ultra-violet and re-radiate it as blue light.

b) Brighteners make fabrics appear whiter and brighter because the blue light can hide any yellowing on the fabrics. Blue light added to the yellow light reflected on old fabrics make them look white.

Drying agents: Sodium sulphate and sodium silicate

Anhydrous sodium sulphate and sodium silicate (Na2S2O3) are used as drying agents to ensure that the detergent in powdered firm is always in a dry condition.

Stabilisers

a) The functions of stabilizers are to prevent the formation of foam.b) In an automatic washing machine, excessive foam can stop the pump working.

So, washing powders for automatic washing machine are made using detergents that are good at removing and emulsifying grease, but do not produced foam.

Fragrances

Fragrances are added to make clothes smell fresh and clean.


Brightener

Cloth

The effectiveness of soaps and detergents as cleansing agents

Advantages of soaps

- Soaps are effective cleansing agents in soft water, that is, water does not contain Mg2+ and Ca2+ ions.

- Soaps do not cause pollution problems to the environment. This is because soaps are made from chemical found in animals and plants. This means that soaps are biodegradable, that is, they can be composed by the action of bacteria.

Disadvantages of soaps

- Soaps are ineffective in hard water, that is, water that contains magnesium and calcium salts.

- In hard water, soaps will react with Mg2+ and thus, soaps do not lather in hard water.- Scum is grey solid that is insoluble in water. It consists of magnesium stearate and

calcium stearate.

Mg2+ (aq) + 2C17H35COO- (aq) (C17H35COO) 2 Mg (s) Stearate ion (soap ion) Magnesium stearate (scum)

Ca2+ (aq) + 2C17H35COO- (aq) (C17H35COO) 2 Ca (s) Stearate ion (soap ion) Calcium stearate (scum)

- Soaps are not also effective in acidic water, for example rainwater containing dissolves acids. H+ ions from acids will react with soap ions to produce carboxylic acids molecular size that are insoluble in water.

C17H35COO- (aq) + H+ (aq) C17H35COOH (s) Stearate ion (soap ion) stearate acid

- Stearic acids and other carboxylic acids do not act as cleansing agents because they exist main as molecules and do not anionic hydrophilic ends (’head’) that dissolves in water.

Advantages of detergents


- Detergents are cleansing agents that are effective in soft water as well as hard water. This is because detergents do not form scum with Mg+ and Ca2+ ions found in hard water.

- The detergents ions (R –O – SO3- and R – SO3

-) react with Mg+ and Ca2+ ions in hard water. However, the magnesium salts and calcium salts which are formed are soluble in water.

2R – O – SO3- (aq) + Mg2+ (aq) (R – O – SO3)2 Mg (aq)

alkyl sulphate ion (detergent) magnesium alkyl suphate (dissolve in water)

2R – O – SO3- (aq) + Ca2+ (aq) (R – O – SO3)2 Ca (aq)

alkyl sulphate ion (detergent) calcium alkyl sulphate (dissolve in water)

Hence, the scum is not formed and the detergents are still active in hard water and lathers easily.

- Detergents are synthetic cleansing agents. This means that the structure of the hydrocarbon chain can be modified to produce detergents with specific properties. Nowadays, different types of detergents have been synthesised for specific uses such as shampoos and dish cleaner.

- Furthermore, detergents are also effective in acidic water because H+ ion is acidic water do not combined with detergents ions.

Disadvantages of detergents

- Most detergents have branched hydrocarbon chains and are non-biodegradable, that is, they can’t decomposed by bacteria. As a result, non-biodegradable detergents cause water pollution.

- Phosphates in detergents act as fertilizer and promote the growth of water plants and algae. When the plants die and decay, they will used up the oxygen dissolves in water. This will decrease the oxygen content in water and kill fishes and other aquatic lives.

- Detergents produce a lot of foam in water. The layer of foam that covers the water surface will prevents oxygen from dissolving in water. This condition will cause fish and other aquatic life it die from oxygen starvation.

- Additives such as sodium hydrochlorite (bleaching agents) releases chlorine gas in water that is acidic. Chlorine gas is highly toxic and kills aquatic life.


FOOD ADDITIVES

FOOD ADDITIVES

Types of additives and examples

- Food preservatives have been used since ancient times. Ancient civilization used salt to preserve meat and fish, herbs and spices to improve the flavor of food.


- Food additives are chemicals that are added to food in small quantities for specific purposes such asa) Making food last longer by preventing the growth of microorganism.b) Making food last longer by preventing the oxidation of fats and oils by oxygen in air.c) Making food taste or smell better.d) Improving the texture of food and to prevent food from becoming liquid.e) Restoring the colour of food destroyed during food processing.f) Adding colouring to food so as to make the food look fresher, more interesting or

more appetizing.

- There are six types of food additives as shown below :

PRESERVATIVES ANTIOXIDANTS

TYPESTABILISERS OF FOOD THICKENERS ADDITIVES

FLAVOURING DYES AGENTS

Types of food additives

Functions of food additives

Preservatives


- Preservatives are chemicals that are added to food to retard or to prevent the growth of microorganism such as bacteria, mould or fungus, so that the food can be stored for a long time.

- In ancient times, food additives from natural sources such as salt, sugar and vinegar were used to preserve food and to make the food taste better.

- Nowadays, synthetic preservatives are use, table below shows the types of preservatives commonly used. Many of the preservatives are organic acids and salts of organic acids.

Preservative Molecular formula Uses Sodium nitriteSodium nitrate

NaNO2

NaNO3

To preserve meat, cheese and dried fish. To prevent food poisoning in canned foods. To maintain the natural colour of meat and to

make them look freshBenzoic acidSodium benzoate

C6H5COOHC6H5COONa

To preserve sauce (olyster, tomato or chilli), fruit juice, jam and margarine

Sulphur dioxideSodium sulphite

SO2

Na2SO3

Used as bleaches and antioxidants to prevent browning in fruit juices.

Maintain the colour and freshness of vegetables.

To prevents the growth of yeast

Antioxidants

- Antioxidants are chemicals that are added to foods to prevent the oxidation of fats and oils by oxygen in the air.

- Foods containing fats or oils are oxidized and become rancid when exposed to air.- When the fats and oils are oxidized, rancid product are formed. This makes the food

unpalatable. The rancid products are volatile organic compound with foul odors (for example, butanoic acid, C3H7COOH).

- Antioxidants are added to fats, oils, cakes, sausages, biscuits and fried foods to slow down the oxidation process so that these foods do not become rancid.


Flavouring agents

- There are two types of flavouring agents: artificial flavours and flavour enhancer. They are added to foods to make them taste better.

- Flavour enhancers have little or no taste of their own. They are chemicals that are added to food to bring out the flavours or to enhance the taste of food.

- An example of a flavour enhancer is monosodium glutamate (MSG). MSG is used to enhance the flavours of other foods.

- Artificial flavour includes sweeteners and other flavours such as peppermint or vanilla. Aspartame and saccharin are examples of artificial sweeteners.

- Both aspartame and saccharin can be used as a substitute for sugar to enhance the sweetness in food and drink. However, the used of saccharin is banned in many countries because it is carcinogenic. Aspartame has largely replaced saccharin as the artificial sweetener or choice.

- Many esters have fruity odours and tastes and are used as artificial flavours. Table below shows some examples of esters that are used in making drinks.

Ester Benzyl ethanoate

Octyl ethanoate

Ethyl butanoate

Flavour Strawberry Orange Pineapple

Stabilisers and thickening agents

- Stabilisers and thickening agents improve the texture and the blending of foods.


- Stabilisers are chemicals that are used to enable oil and water in the food to mix together properly in order to form an emulsion of oil and water. Examples of stabilizers are gelatin and acacia gum.

- Stabilisers are added to improve the texture of foods. For examples, stabilisers are added to ice-cream and peanut butter to keep them smooth and creamy.

- In the presence of stabilisers, the emulsion of oil does not separate from water. This means that the stabilisers improve the stability of some foods such as ice-cream and salad dressings (mayonnaise).

- Without stabilisers, ice crystals would form in ice-cream, particles of chocolate would settle out of chocolate milk, oil and vinegar in salad dressing will separate as soon as mixing is stopped.

- Thickening agents are chemicals that are added to foods to thicken the liquid and to prevent the foods from becoming liquid. Thickening agents (also called thickeners) absorb water and thicken the liquid in foods to produce a jelly-like structure.

- Most thickening agents are natural carbohydrates. Gelatin and pectin are added to help jams and jellies to set.

Dyes

- Dyes (colouring agents) are chemicals that are added to foods to give them colour so as to improve their appearance.

- Some foods are naturally coloured, but the colour is lost during food processing. The foods industry uses synthetic food colours to :

a) Restore the colour of food lost during food processing.b) Enhance natural colours, so as to increase the attractiveness of foods.c) Give colour to foods that do not have colour.

- Some dyes are naturally plant pigments while others are synthetically prepared. The synthetic colours used in foods are azo and triphenyl compounds. Both these compounds are organic compounds.

- The synthetic dye, brilliant blue, is an example of triphenyl compound. The synthetic dye, tartrazine and sunset yellow are examples of azo compounds.

- Azo compounds are organic compounds containing the diazo group, - N = N -, and are usually yellow, red, brown, black in colour. Triphenyl compounds are organic compounds containing three phenyl groups, -C6H5, and are usually green. Blue or purple in colour.

Effect of food additives on health


- The types of food additives allowed and the quantity permitted are controlled by the 1983 Food Act and the 1985 Food Regulation.

- The permissible quantity depends on the type of food and the food additives. For example, benzoic acid added must not exceed 800 mg per kg in cordial drinks, whereas sodium nitrite must not exceed 100 mg per kg in meat product.

- The excessive intake of food additives for a prolonged period of time will ruin our health. The side effects arising from taking food additives are allergy, cancer, brain damage and hyperactivity.

Allergy

a) Food additives such as sodium sulphite (preservative), BHA and BHT (antioxidants), MSG (flavouring) and some food colours (e.g, Yellow No. 5) can cause allergic reactions in some people.

b) The symptoms of MSG allergy are giddiness, chest pain and difficulty in breathing. This condition is called the ‘Chinese restaurant syndrome’

c) The presence of sodium nitrate or sodium nitrite in food can cause ‘blue baby’ syndrome that is fatal for babies. This syndrome is due to the lack of oxygen in the blood. Hence, the use of nitrate and nitrite is allowed in baby foods.

Cancer

a) Chemicals that cause cancer are called carcinogens. Sodium nitrite (a preservative) is a potent carcinogen.

b) The nitrite reacts with the amines in food to produce nitrosamine which can cause cancer.

Brain damage

Excessive intake of nitrites for a prolonged period of time can cause brain damage. In this condition, the supply of oxygen to the brain is disrupted and this cause brain damage.

Hyperactivity

a) Food additives such as tartrazine can cause hyperactivity.b) Children who are hyperactivity become very active, find it difficult to relax or

sleep and are very restless.

Reading the Food Label


- You must read the label on the food package to identify a) Brand nameb) The net weightc) The halal symbol for Muslim consumersd) The nutrient content (for example, carbohydrates, proteins and fats, minerals and

vitamins).e) Food additives usedf) Expiry dateg) Address of the manufacturer

- Food additives listed in the food labels are usually represented by the code number – E. This code number shows that the food additives have been approved.

- Figure 5.5 shows a typical food label for an orange drink.

absorbic sodium expiry

acid benzoate date

XYZ Orange drinkIngredient: Water, sugar,

citric acid,E330 Use before:Stabilisers: E466, preservative E211 31-1-2010 Sweetener: aspartameColouring agents: E110, E102, vitamins A and D

yellow-orange (dye) tartrazine (dye)

Figure 5.5: A typical food label

The rationale for using food additives

Advantages

1. To prevent food spoilage


a) Oxidation and microorganism (bacteria, fungi) are the main causes in the decomposition of food. In hot climate, meat and fish rot easily. The use of preservatives is an effective way to prevent food spoilage. If the used of preservatives is an effective way to prevent food spoilage.

b) If preservatives are not used, food spoilage might drastically reduce the food supply, making for costlier food.

c) Few deaths are associated with the used of food additives. However, many people have die due to food poisoning caused by bacterial toxins.

2. For medical reasona) Aspartame and sorbitol are used to make food and drink sweet without using sugar.

These food additives are particularly useful as artificial sweeteners for diabetic patients.

b) Artificial sweetener give the sweet taste but without adding calories to the food. Thus, they can be used to reduce obesity.

Disadvantage

1. Eating food additives such as preservatives, antioxidants and flavour enhancers is excess quantities over a long period of time is detrimental to health.

2. Some food additives are used to make foods look more appealing. These additives have little nutritional value. Eating such foods increases the risk of health hazard.

3. Some foods are fortified with excess amounts of nutrients, such as vitamins A and D, or of trace elements, such as copper and zinc. Eating foods with excessive amounts of nutrients can ruin our health.

Live without food additives

Imagine life without food additives. The following situations will occur.

1. Food spoilage will drastically reduce the food supply. This will result in food shortages around the world.

2. Diseases will flourish again due to deficiencies of vitamins and minerals in our food.3. Loss of appetite will be common particularly among the younger generation because our

food will not look, taste, and smell good and this will affect their appetites.


MEDICINE

MEDICINESources and uses of traditional medicines

1. A medicine is a substance used to prevent or cure diseases or to reduce pain and suffering due to illnesses.


2. Traditional medicines are medicines derived from natural sources such as plants and animals without being processed chemically.

3. Since ancients, mankind had used various types of plants and roots, animals and animal part to cure diseases.

4. Medicines obtained from plants are known as herbal medicines. The sources and uses of some herbal medicines are shown in table below :

Plant Part of the plant used Uses

Garlic Corm - For preventing flu or asthma attack - For reducing high blood pressure

Ginger Rhizome (horizontal underground stem) and leaves

- For treating stomach pain due to wind in the stomach

- For supplying heat energy to keep the body warm

- For preventing flu attackAloe vera Leaves - For preventing itchy skin

- For treating burns (scalding) on the skinLemon (lime) Fruits - For treating boils or abscesses on the skin

- For preventing flu attack- For treating skin diseases

Quinine Bark of Chinchona tree

- For treating malaria- For preventing muscle cramps

Ginseng Roots - As a tonic to improve the overall health of human beings

- For increasing energy, endurance and reducing fatigue

Lemon grass Stem/leaves - Has antibacterial and antifungal properties- For treating cough

Tongkat Ali Roots - As a tonic for after a birth and general health

-Some examples of herbal medicine-


Modern medicine

- Modern medicines can be classified as follows based on their effects on the human body.

- Some examples of modern medicines are:a) Analgesicsb) Antibioticsc) Psychotherapeutic drugs

Type of modern drug ExampleAnalgesics Aspirin, paracetamol, codeineAntibiotics Penicillin, streptomycinPsychotherapeutic drugs Stimulant, antidepressant, antipsychotic

Fucntion of each type of modern drug

Analgesics

- Analgesics are medicines that relieve pain. Examples of analgesics are aspirin, paraccetamol, and codeine. Analgesics are sometimes called painkillers.

- Aspirin and paracetamol are mild painkillers whereas codeine is powerful painkillers.- Analgesics relive pain but do not cure the disease. Table 5.6 shows the chemical aspect

and functions of some analgesics.

Type of Chemical aspect Function


analgesic

Aspirin

IUPAC name: acetyl salicylic acidFunctional groups: a carboxylic acid group and ester group COOH carboxylic acid

O ║ O – C – CH3

ester group

Thus, aspirin is acidic in nature.

- Relief pain and has anti-inflammatory action.

- Used to:a) Reduce feverb) Relieve headaches, muscle

aches and joint aches.c) Treat arthritis, a disease

caused by inflammation of the joints.

d) Act as an anticoagulant. It prevents the clotting of blood and reduces the risk of heart attacks and stroke.

Paracetamol

Structural formula: H O │ ║HO N – C – CH3

Thus, unlike aspirin, paracetamol is neutral in nature.

- Similar to aspirin in its effects but it does not reduce inflammation.

- Reduces or relieves flu symptoms such as fever, bone aches and runny nose.

CodeineCodeine is an organic compound that contains the elements carbon, hydrogen, oxygen and nitrogen.

- Used relieves minor to moderate pain. It is more powerful than aspirin and paracetamol but less powerful than morphine. Codeine and morphine are narcotic drugs.

- Also used in cough mixtures for suppressing coughs.

Table 5.6 Types of analgesics and their functions


Antibiotics : Antibacterial medicine

- Antibiotics are chemicals that destroy or prevent the growth of infectious microorganism.

- Two examples of antibiotics are penicillin and streptomycin.- Antibiotics are used to treat diseases caused by bacteria.- Antibiotics are not effective against diseases caused by viral infections such as influenza,

measles, or small pox.

Penicillina) Penicillin is derived from the mould Penicillium chrysogenum.b) Penicillin is used to treat diseases, caused by bacteria, such as pneumonia,

gonorrhea and syphilis.c) Penicillin is only effective on certain bacteria. For example, it cannot be used to

treat tuberculosis.

- Streptomycin is the antibiotic that is effective in treating tuberculosis.

Psychotherapeutic medicines

- Psychotherapeutic medicines are a group of drugs that change the emotional and behavior of the patient and are used for treating mental or emotional illnesses.

- Table 5.7 shows the types and functions of psychotherapeutic drugs.

Type of psychotherapeutic drug

Function Examples Comments

StimulantsThese are drugs that stimulate (excite) the

- To maintain or increase alertness

Caffeine - It is found in coffee, tea, and Cola drinks

- It is a weak,


activity of the brain and the central nervous system

- To counteract normal fatigue

- To elevate mood

naturally occurring stimulant

Amphetamine - A strong synthetic stimulant

- It increases the heart and respiration rates as well as blood pressure

AntidepressantsThese are drugs that increase the brain’s level of neurotransmitters and thus improve mood

- To alleviate depression

- To relieve anxiety or tension

- To make a person feel calm and sleepy

- Barbiturate - Tranquiliser

They are substances that depress the central nervous system and cause drowsiness

Antipsychotic medicine To treat mental illness such as schizophrenia (madness)

- Lithium carbonate (Li2CO3)

- Chloropromazine- Haloperidol

- Mental (psychotic) patients have extreme mood swings. Their mood changes rapidly from high spirits to deep depression

- Antipsychotic medicine do not cure mental illness but it can reduce some of the symptoms to help the person live a more normal life

Table 5.7 Types and functions of psychotherapeutic drugs

Side effects of traditional medicines


- It is generally believed that traditional medicines have little side effects compared to modern medicines. In fact, traditional medicines are sometimes used to counteract the side effects of some modern medicines.

- However, taking high doses of quinine for a prolonged period may cause hearing loss. German health officials recently reported 40 cases of liver damage which were linked to the herbal medicine containing kava-kava.

- While the use of traditional medicine is rising globally, health experts have insufficient data about how it affects patients.

- The World Health Organization (WHO) hopes to set up a global monitoring system to monitor the adverse side effects of traditional medicines.

Side effects of modern medicines

- Table 5.8 shows the side effects of modern medicine.

Type of modern drug

Side effects

Aspirin Can cause bleeding in the stomach because aspirin is vey acidic. Can cause allergic reactions, skin rashes and asthmatic attacks

Amphetamines

People who abuse amphetamines are excitable and talkative. Psychologically additive and can cause heart attack. Can cause anxiety, sleeplessness, aggressive behavior and decrease

appetite. Can cause enlarged pupils, heavy perspiration and trembling hands.

Codeine Can cause addiction.

Penicillin Can cause allergic reactions. Can cause death for people who are allergic to it.

Streptomycin Can cause nausea, vomiting, dizziness, rashes and fever. Can cause loss of hearing following long-term use.

Stimulants Can cause addiction.Antidepressants

Can cause addiction. Can cause headaches, grogginess and loss of appetite.

Antipsychotic drugs

Can cause dry mouth, blurred vision, urinary retention, constipation. Can cause tremor and restlessness. Sedation (make people calmer, or to make people sleepy)

Table 5.8 Side effects of modern medicine

Correct ways of using medicines


In taking any medicine, we should know why the medicine is prescribed, how the medicine should be used, what special precautions should be followed, what special diet should be followed, what is the side effect and what storage conditions are needed. In addition, we should note the following points:

a) Self-medication Do not prescribe medicines for yourself (self-medication) or for other people. Discuss with your doctor and listen to him concerning the medicine to be taken.

b) Follow the instructions given Follow the instructions given by your doctor or pharmacist concerning the dosage and method of taking the medicine.Dosage: Never take larger or more frequent doses and do not take drug for longer than directed.Method of taking: Different drugs are taken in different ways. For example, medicines that are acidic (such as aspirin) must be taken after food. If taken on an empty stomach, the medicine will damage the stomach lining. Conversely, antadic tablets are usually taken before food.

c) Medicines for adult and children Medicines for adult should not be given to children and vice versa.

d) Use of antibiotics Complete the whole course of antibiotic treatment given by your doctor. Do not stop taking the antibiotic just because you are already feeling well. If not, the remaining bacteria will mutate and develop resistance to the antibiotic and render it ineffective in the future.

e) Side effects Visit the doctor immediately if there are symptoms of allergy or other effects of the drugs.

f) Expiry date Like foods, medicines also have expiry date. Do not take medicines after their expiry dates.

Appreciating the existence of chemicals


- Since the last 100 years, thousands of new chemicals are synthesized. These new chemicals include synthetic polymers, composite materials, antibiotics, detergents and modern medicine. These chemicals improve the quality of life.

- Modern chemical substances have brought enormous benefits to mankind. However, the chemicals have side effects on life and the environment. We practice proper management of chemicals towards a better life, hygiene and health.

- Intensive scientific research must be carried out to produce new substances and this takes time. Scientists must have patience, meticulousness and perseverance for their research and development to produce new products.

- Modern living depends on chemical substances. Try to imagine the world without chemicals. For example, without petroleum, the transport systems will break down; without modern medicine, diseases will spread and without soap and detergent, the world will become dirty and less hygienic.


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