Chapter 5: Chemicals For Consumer

YEAR 2009

CHEMISTRY FOLIO

CHAPTER

5:

CHEMICALS FOR CONSUMER

NORSAFINAH BINTI MOHD TUMIRAN | 5 DORISIA

CONTENTS No.

Title

Page

5.1

Soap and Detergent

2

5.2

Food Additives

6

5.3

Medicine

7

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5.1 : Soap and Detergent

Soap • •

Salt that are formed by neutralization between a fatty acid and an alkali. One example of soap is sodium palmitate, CH₃(CH₂)₁₄COONa. It is formed when palmatic acid is neutralized by sodium hydroxide, NaOH.

CH₃(CH₂)₁₄COOH(aq) + NaOH(aq) → CH₃(CH₂)₁₄COONa(aq) + H₂O(l) Detergent • • •

Salt that are formed by neutralizing an alkyl hydrogen sulphate with an alkali. One example of detergent is sodium lauryl sulphate Detergents may contain many other substances in addition to the substances that does the cleaning and also to make it more effective. These substances are called additives

Biological enzymes are catalyst that increase the detergency or cleaning power of a detergent. Whitening agents include bleaches such as sodium perborate. They release chlorine and oxygen that remove stains and make clothes become whiter and cleaner.

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Preparation of detergent •

Detergents are made using raw material obtained from petroleum

Production of lauryl hydrogen sulphate CH₃(CH₂)₉CH₂OH + H₂SO₄ CH₃(CH₂)₉CH₂OSO₃H + H₂O

2.

neutralization of lauryl hydrogen sulphate

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

DETERGENT

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Preparation of soap • • • • •

Oils and fats are esters formed from glycerol and fatty acids. It made up through heating oils or fats with an alkali such as sodium hydroxide, NaOH. The oil or fat molecules are “broken up” or hydrolyzed to glycerol and fatty acids. This reaction is the reverse of esterification (saponication) The fatty acids formed then react with sodium hydroxide, NaOH to form a salt (soap).

Saponication of oils or fats O ll R’—C—O—CH₂ O ll + R”COOH + R”’COOH R”— C—O—CH + 3H₂O O

HO—CH₂ OH⁻

l HO—CH + R’COOH l HO—CH₂

fatty acids

ll R”’—C—O—CH₂

glycerol

Neutralization of fatty acids R’COOH + R”COOH + R”’COOH + 3NaOH + 3H₂O

R’COONa + R”COONa + R”’COONa

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The cleansing action of soap and detergent • • •

One part of the soap and detergent anion is negatively charged (polar end). -It dissolves in water. It is hydrophilic or “likes water”. The other part has no charge (non-polar end) -It dissolves in oil or grease. It is hydrophobic or “hates water”. These two parts work together to remove grease.

hydrophobic part (non-polar end)

hydrophilic part

(polar end)

•

• • •

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 ‘heads’ (hydrophilic) of soap ions or detergents ions dissolves in water (b)The hydrocarbon ‘tails’ (hydrophobic) of soap or detergent ions dissolves in the layer of grease. If the water is agitated slightly, the grease begins to lifted off the surface. When the cloth is rinsed with water, the droplets will be carried away Heating and stirring may help to loosen the dirt particles from the material being washed.

The effectiveness of the cleansing action of soap and detergent Property Cleaning power Ease of rinsing

pH

Soap Less powerfull It is difficult to wash away all soap on clothes. The soap that remains leave and odour and spoils the fabric Slightly alkaline

Molecular structure

Determined by the fatty acids found in the oil or fat used to produce soap

Formation of scum

Forms scum with hard water

Detergent More powerfull Rinse out well from clothes

Can be controlled to suit the cleaning task Can be modified to suit the cleaning task. For example, a detergent can be made specially for cleaning toilet bowls. Does not form scum with hard water

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5.2 : Food Additives Uses of food additives To make food last longer (to extend the shelf life) To make foods taste better and look better

Types of food additives Preservatives: sodium nitrite, sodium benzoate Antioxidant: ascorbic acid Flavouring: Monosodium glutamate(MSG), aspartame Stabiliser and thickener: gelatin and acacia gum Dye: azo compounds, triphenyl compounds

Effects on health Allergy: MSG Carcinogenic: NaNO₂ Brain damage Hyperactivity

Functions of food additives Preservatives: to inhibit or prevent the growth of moulds, yeast and bacteria that spoil foods Antioxidants: to prevent spoilage of food due to oxidation by oxygen Flavouring agents: to enhance the taste of food Stabilisers and thickeners: to improve the texture of foods Colouring agents: to restore the colour or to enhance the natural colour

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5.3 : Medicine •

A medicine is a substances used to prevent or cure disease or to reduce pain and suffering due to illness.

PlantLocal nameUsesAloe veraLidah buayaSap used to relieved pain from burnsBetelSirehLeaves relieved sore eyesBitter gourdPeriaFruit used to cure diabetesCoconutKelapaYoung coconut water reduces feverGarlicBawang putihReduces infection and hypertensionGingerHaliaReduces inflammation and improves blood circulation and digestionGinsengGinsengRoots maintain good healthHibiscusBunga RayaLeaves relieves headache and hair lossTurmericKunyitCures pimples

Traditional medicines Derived from plants and animals

Medicines

Modern medicines Chemicals that are extracted from plants and animals

Type of modern medicineFunctionExamplesAnalgesicsRelieve painAspirin, paracetamolAntibioticsKill or inhibit growth of infectious bacteriaPenicillin, streptomycinPsychotherapeutic medicinesControl symptoms of mental illnessStimulants, antidepressants

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Side effects of medicines • • •

Both traditional and modern medicines have side effects Some traditional medicines help people lose their weight by speeding up their metabolism. The side effects are an increase in blood pressure and heart rate Birth control pills are an example of modern medicine. Women who use them experience side effects such as hypertension, acne, and abnormal bleeding.

Correct ways of using medicines • • •

Use the correct amount or dosage and using it for the correct purpose For example, using antibiotics to treat infections caused by viruses is drug misuse. This is because antibiotics have no effect on viruses. Drug abuse is using drug for its intoxicating effect. For example, the use of Morphine, Viagra and ecstasy pills.

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