the cleaning action of soap and detergent...

1. The cleansing action of soap or detergent depends on their chemical bonding and

structures.

a) The ionic ‘head’ (negatively charged) is soluble in water (hydrophilic) but

insoluble in oily layer.

b) The long hydrocarbon ‘tail’ (neutral) is insoluble in water (hydrophobic) but

soluble in oily layer.

2. Oil cannot be washed away from clothing with water because oil (a covalent
molecult0 is insoluble in water.


3. Lifting greasy dirt from the surface cloth. When soap or detergent is added to the
dirty surface of a piece of cloth covered with a layer of oil or grease.

a) The negatively charged ‘head’ (hydrophilic) of soap ions or detergent ions

dissolves in water.

b) The hydrocarbon ‘tail’ (hydrophobic) of soap or detergent ions dissolves in

the layer of grease.

4. I the water is agitated slightly, the grease begins to be lifted off the surface. This
cause by the forces of attraction between the water molecules and the negatively
charged heads.

5. On further agitation during washing, the greasy dirt is lifted from the surface.


6. Emulsifying dirt in water

a) Soaps and detergents can act as emulsifying agents to emulsify oils and

grease.

b) The process of emulsification breaks large drops of grease into smaller

droplets that floats in water. The greasy droplets repel on another because

they carry the same charge. As a result, the grease is suspended in the

solution.

c) When the cloth is rinsed with the water, the droplet will be carried away.

d) The cleaning process become more efficient in the water containing the

soap or detergent solution is stirred

mAcaM mAnA dETerGeNt diJaDiKan??

*A synthetic detergent,a sodium alkaly sulphate called dodecylsulfate,will be prepared by reacting dodecyl alcohol (dodecanol) with sulfuric acid


        CH3(CH2)9CH2OH+H2SO4   > CH3(CH2)9CH2OSO3H+H2


         dodecanol                 sulfuric acid         dodecylsulfate

*The resulting dodecysulfate is converted to the sodium salt by a reastion with sodium hydroxid



CH3(CH2)9CH2OSO3H+NaOH >CH3(CH2)9CH2OSO3Na+H2O

                        

       dodecylsulfate                          sodium dodecylsulfate

a

the additives in detergent and their respective function

1. Modern detergents used for washing clothes usually contains a few types of
additives to :
                                          a) Increase their cleaning power.

b) Make them attractive and saleable.

2. Only about 20% of the substances in a detergent are cle4ansing agents (sodium
alkyl sulphate or sodium alkylbenzene sulphonate). The other substances are
additives. The examples of addictives and their functions are described as follows:


3. Builders : Sodium tripolyphosphate (Na5P3O10)

a) Sodium tripolyphospathe is usd 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.

4. Whitening / bleaching agents : sodium perborate

a) Bleaches (bleaching agents) remove coloured stains by oxidation process.

When coloured stanis are oxidized, the colour will disappear.

b) The whitening (bleaching) agents commonly used in detergent are 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 colourful 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.

5. 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.

6. 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.

7. 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.

8. Stabilisers

a) The functions of stabilizers is to prevents 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.

9. Perfumes

Perfumes are added to make clothes smell fresh and clean.

the effectiveness of the cleansing action of soap and detergent

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


2. 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
1. Soaps are ineffective in hard water, that is, water that contains magnesium and
calcium salts.


2. In hard water, soaps will react with Mg2+ and thus, soaps do not lather in hard
water.


3. Scum is grey solid that is insoluble in water. It consists of magnesium stearate and
calcium stearate.


4. 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.


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


Advantages of detergents
1. 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.


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


3. 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.


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


Disadvantages of detergents
1. Most detergents have branched hydrocarbon chains and are non-biodegradable,
that is, they cannot decomposed by bacteria. As a result, non-biodegradable
detergents cause water pollution.


2. Phosphates in detergents act as fertilizers 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.


3. 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 ti die from oxygen starvation.


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

                                                                ~ detergent~

        

the correct usage of modern medicine

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

1.Self-medication

Do not prescribe medicines for yourself (self-medication) or forother people. Discuss with your doctor and listen to himconcerning the medicine to be taken.

2.Follow the instructions given

Follow the instructions given by your doctor or pharmacistconcerning the dosage and method of taking the medicine.

3.Medicines for adult and childrenMedicines for adult should not be given to children and viceversa.

4.Side effectsVisit the doctor immediately if there are symptoms of allergyor other effects of the drugs.

5.Expiry dateLike foods, medicines also have expiry date. Do not takemedicines after their expiry dates.

possible side effect of using modern medicine

 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).

the functions of each type of modern medicine

Analgesics

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

2.Aspirin and paracetamol are mild painkillers whereas codeineis powerful  painkillers.

3.Analgesics relive pain but do not cure the disease.

4.Aspirin : pain relief and anti-inflammatory action

a)The IUPAC name of aspirin is acetyl aslicylec acid. Aspirin contains two functional groups, a carboxylic acid group and the ester group. Thus, aspirin is acidic in nature.

b)Uses of aspirin Aspirin reduces fever and inflammable as well as relives pain. Aspirin is used to :

(i)Reduce fever

(ii)Relieve headaches, muscle aches and joint aches

(iii)Treat arthritis, a disease caused by inflammation of the joints

(iv)Act as an anticoagulant. It prevents the clotting of blood and reduce the risk of the heart attack andstrokes.

5.Paracetamol

a)Paracetamol have the following structural formula. Thus, unlike aspirin, paracetamol is neutral in nature.

b)Paracetamol is similar to aspirin in its effects (that is, reduces fever and relieves pain) but it does not reduce inflammation.

c)Paracetamol also reduces or relieves flu symptoms sucha s fever, bone aches and runny nose.

6.Codeine

a)Codeine is an organic compound that contains the elements of carbon, hydrogen, oxygen and nitrogen.

b)Codeine is an analgesics and is used to relive mirror tomoderate pain. Codeine is more powerful than morphine. Codeine and morphine are narcotic drugs

c)Codeine is also used in cough mixtures for suppressing coughs.

Antibiotics : antibacterial medicine

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

2.Two examples of antibiotics are penicillin and streptomycin.

3.Antibiotics are used to treat diseases caused by bacteria.

4.Antibiotics are not effective against diseases caused by viral infections such as influenza, measles, or small pox.

5.Penicillin

 a)Penicillin is derived from the mould Penicillium notatum.

b)Penicillin are 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.

6.Streptomycinis 

the antibiotic that is effective in treating tuberculosis.

Psychotherapeutic medicines

1.Psychotherapeutic medicines are a group of drugs for treating mental or emotional illnesses.

2.Psychotherapeutic drugs can be divided into a few groups as shown below :

• stimulants, ex: caffeine, amphetamine 
• antidepresant, ex: prozac
• antipsychotic agents, ex: chloropomazin 

3. Stimulants

a)Stimulants are naturally occurring or synthetic drugs that stimulate (excite) the activity of the brain and central nervous system.

b)Adrenaline is a stimulant that the body produces when it needs to prepare for demanding or energetic activities.

c)Stimulants make a person more alert, more energetic,less tired and more cheerful.

d)Examples of stimulants are caffeine and amphetamines.Caffeine is a week, naturally occurring stimulant and isfound on coffee, tea and Cola drinks.

e)Amphetamines are strong synthetic stimulants andincrease alertness and physical ability.

f)Amphetamines increase the heart and respiration rates,as well as the blood pressure. As a result, it causes thebody to postpone the need of sleep and can reverse,partially and temporarily, the symptoms of fatigue.

4.Antidepressants

a)Depression is a chronic illness. Most cases of depressionare caused by a chemical imbalance in the brain.

b)People experiencing depression feel hopeless. Theyexperience a loss of interest in everyday activities suchas work or hobbies.

c)There is a strong correlation between the amounts of special chemicals (called neurotransmitters) in the brainand a person’s mood. If these chemicals get too low, theperson may feel depressed.

d)Antidepressants are medicines that increase the brain’slevel of neurotransmitters, thus improving mood.

e)Antidepressants make a person feel calm and sleepy.

5.Antipsychotic medicines

a)Psychosis is the serious mental illness in which peoplelose touch with reality. People with psychosis may,

i. Hear voice and see things that are not really there(hallucinations)

ii. Have belief that are not based on reality (delusions)

b) In psychiatry, there are a number of disorders that areclassified under ‘ psuchosis’, such as schizophrenias(madness), psychotic depression, mania and so on.

c) Psychotic patients have extreme mood swings. Theirmood changes rapidly from high spirit to deepdepression.

d) Antipsychotic medicines do not cure symptoms to helpthe person live a more normal life.

types of modern medicine

1.Before the 20th century, most medicines were extracted from plants (herbal medicines). Since 1900. Thousands of modern drugs have been synthesized from organic compound.

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

3.Some examples of modern medicines are analgesics, antibiotics, psychotherapeutic drugs.

4.Modern drugs have a trade name and a generic name. For example, the analgesic aspirin (generic name) is sold under different brand names such as Caprin and Disprin. Similarly, paracetamol (generic name) is sold under the trade name of Panadol. 

5.Modern medicines usually contain a mixture of active ingredients prepared in different forms, such as capsules, pills, solutions or suspensions. For example, Alka-Seltzer (used as an antacid) contains sodium bicarbonate, citric acid and aspirin. It is the sodium bicarbonate then neutralizes the excess stomach acid.

the effects of food additives on health and the environment

1.The types of food additives allowed and the quantity permittedare controlled by the 1983 Food Act and the 1985 FoodRegulation.

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

3.The excessive intake of food additives for a prolonged periodof time will ruin our health. The side effects arising from takingfood additives are allergy, cancer, brain damage andhyperactivity.

4.Allergy
a) Food additives such as sodium sulphite (preservative),BHA and BHT (antioxidants), MSG (flavouring) and somefood colours (e.g, Yellow No. 5) can cause allergicreactions in some people.
b) The symptoms of MSG allergy are giddiness, chest painand difficulty in breathing. This condition is called the‘Chinese restaurant syndrome’
c) The presence of sodium nitrate or sodium nitrite in foodcan 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 babyfoods.

5.Cancer
a) Chemicals that cause cancer are called carcinogens.Sodium nitrite (a preservative) is a potent carcinogen.
b) The nitrite react with the amines in food to producenitrosamine which can cause cancer.

6.Brain damage
Excessive intake of nitrites for a prolonged period of time cancause brain damage. In this condition, the supply of oxygen tothe brain is disrupted and this cause brain damage.

7.Hyperactivity
a) Food additives such as tartrazine can causehyperactivity.
b) Children who are hyperactivity become very active, findit difficult to relax or sleep and are very restless.