Chemistry in Everyday Life

7/18/2019 Chemistry in Everyday Life

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[ CHEMISTRY IN EVERYDAY LIFE ]NCERT 12TH STD

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Introduction

Chemistry - ubiquitous in every part of our lives:

Cleanliness - soap, detergents , tooth pastes.

Clothes - synthetic fibres, colours by chemicals.

Food - made up of org/inorg chemicals.

Medicines - chemicals

Explosives, fuels, rocket propellants, building & electronic material, human beings themselvesand their control by various chemicals.

Drugs and their clarification

Drugs - chemicals of low molecular masses (~ 100 - 500 u)

- interact with macro molecular targets produce biological response.

higher doseif

therapeutic & useful

called

medicines.

used in

diagnosis / prevention / treatment of diseases.(Chemotherapy).

potential poisons

Classification Basis

Pharmacologicaleffect

for treatment ofvarious types of problems

Eg. Analgesic: pain killersAntiseptic: kill / arrest -growth of organisms.

Drug Action Chemical structure Molecular targets

action of a drugon a particular biochemical process.

drugs with similar chemical structureare grouped - oftenhave similar p.effect

drugs targetting thesame class of targets(Eg. (CH, lipids, proteins,nucleic acids))

Eg. Histamine

Eg. Sulphonamides havecommon structure:

causes

inflammationin body

Antihistamines-inhibittheir action.

generally shown by drugs possessingsome commonstructural features.

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Drug - target interaction

Macromolecules (MM) of biological origin perfom various functions in body..

Eg. Proteins - biological catalysts - enzymes.

- crucial to communication system - receptors.

- carry polar molecules across membranes - Carrier proteins

Nucleic Acids - coded genetic information of the cell.

lipids and CH - structural parts of cell membrane.

Enzyme as drug targets

(a) Catalytic action of enzymes

enzymes are selective catalysts. i.e. they catalyse rxn only of a specific shape of reagents:

Here, as can be seen - the enzyme holds the substracts in a suitable position - can be

attacked by reagent now. (the binding is achieved by - IB, HB, VdwF

or dipole-dipole

interaction).

The enzyme - may provide FGs - that attack the substrate for a chem. rxn.

(b) Drug - enzyme interaction

Drugs inhibit activities of enzyme - by blocking the binding site or inhibiting the catalytic

activity of enzyme - called enzyme inhibitors.

2 ways:

Competitive inhibitors: They have same shape as substrate and compete with it to block

the enzyme:

( Shorthand Notation : w/ means with ; w/o means without ; wh/ means which )

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Attacking allosteric site: Some drugs attack a site (allosteric site) other than the active

site - forming bond with enzyme - rendering the enzyme to change shape of active site - and

so, substrate can’t recognise it - and enzyme is blocked (esp. if covalent bond is formed w/

drug wh/ can’t be broken easily). - in such cases, body degrades this “enzyme - inhibitor”

complex and synthesises a new enzyme.

Non-competitive inhibitor changes the active site of enzyme after binding at allosteric site.

Receptors as drug targets

Receptors: proteins crucial to body’s communication process - embedded in cellmembranes as shown below:

– a small part of RP (receptor proteins) - projects out of the surface of the membrane and

opens on the outside region.

In body:communication by

neurons neuronschemical messengers

neurons muscles

received at binding sites of RP - shape of RP changes as CM is received - this transfers the

message into the cell (so, msg conveyed by CM w/o entering the cell).

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Different RP - interact - different CM - show selectivity due to different shape, structure

and amino acid composition.

Antagonists: drugs that bind to RP - inhibit its natural function (used when blocking of

msg is required).

Agonists: mimic the natural messenger by switching on the receptor (used when there is a

lack of natural messenger).

Therapeutic Action of Different Classes of Drugs

Antacids: NaHCO3 (or) Al(OH)

3 /Mg(OH)

2 - react with excess acid produced in stomach

(wh/ if unchecked - develop into ulcers) - but excess3

HCO makes the stomach alkaline -

can trigger production of even more acid. But M(OH)x - insoluble - don’t increase pH

above neutrality - So, better.

Control only symptoms - not good in treatment - and in advance stages when ulcers becomelife threatening - only treatment is operating and removing affected part of the stomach.

Anti histamines (AHM): Histamines (HM) - stimulate secretion of pepsin and HCl - in

stomach - by interacting with receptors present in stomach wall.

Some drugs - prevent interaction of HM w/ RP lesser secretion of acid.

Egs: Cimetidine (Tegamet) and ranitidine (Zantac):

So, these are AHM that act as antacids.

Vasodilator - relaxes muscles like in the walls of blood vessels - contracts smooth muscles in

bronchi and gut. HM is a vasodilator. HM - also responsible for - nasal congestion

associated w/ common cold and allergic response to pollen.

Other AHM (synthetic) - brompheniramine (Dimetapp) and terfenadine (Seldane):

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Act by - competing w/ HM for binding sites of receptor where HM exerts its effect. So, these

AHMs are anti-allergic. (But why do these not act as antacids too? - because antiallergic and

antacid drugs work on different receptors.

Mnemonics:

C(o)i met hits

said

Tu-ga-mate

Rani T(a)i

So, beautiful that jaan take

to remove here acidity - then they (d)dine

bro m(o) on p ir's hen NH . Ki allergy gone hen was so happy2

that it went to a and paid a to use it.tap(p) dime

Terfe na(g)dine Sel danein em ka because of her allergy

Neurologically Active drugs

(a) Tranquilizers

- affect msg transfer mechanism from nerve to receptor .

Nor adrenaline (mnemonics: Nor - blood rushing - adrenaline). - a neurotransmitter - role in

mood changes. - if low - signal sending activity is also low results in depression - to

counter - anti depressants are required - they inhibit enzymes wh/ catalyse the degradation

of noradrenaline -then, it is slowly metabolised and activates its receptors depression

gone. Drug Egs: Iproniazid and phenelzine (Nardil). (fig. below):

mnemonics:

I pron zid

phene l zine nor dil

(am) (ia) to - leads me to depression - to come out I use neither a

(y) bottle ka .

This was an eg. of tranquilisers - used for treatment of stress, irritability or excitement

- by inducing a sense of well - being

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Other tranquilisers:

Chlordiazepoxide and meprobamate : mild tranquilisers for releasing tension.

Equanil: to control depression and hypertension.

mnemonics:

Ch lor diaz me proba m ateam - was tensed - went and her l I .O

Equal (ni) l

depression

hypertension

Derivatives of barbituric acid - called barbiturates - (veronal, amytal, nembutal, luminal,seconal) - imp. class of tranquilisers- are hypnotic - sleep producing agents.

Other Egs. of tranquilisers: Valium, Serotonin.

mnemonics:

When ica visited i , it ated, lives of every dwhose lives were nothing but till then, but now under herhypnotism, they fell asleep

Veron Am ty lumin secon nembubarbaric

All h with our are brought down using tranquilisersS er Val

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(b) Analgesics Non - narcotic (non-addictive)

Narcotic

reduce pain w/o causing consciousness impairment, mental confusion, incoordination or

paralysis or some other disturbance of nervous system.

Non-narcotic: Eg. Aspirin and paracetamol.

Aspirin: prostagladins - stimulate inflammation tissue-cause pain.

its creation stopped by

Aspirin. (esp. for skeleton pain due to arthritis, reduce fever

(antipyretic), prevent platelet coagulation)

Also, has anti blood clotting action used in prevention

of heart attacks.

Narcotic: Eg. Morphine and its homologues (Eg. Heroin, Codeine.) When given in medicinal doses - relieve pain and produce sleep

in poisonous doses - stupor, coma, convulsions, ultimately death.

called opiates (as obtained from opium poppy).

used also for : post operative pain, cardiac pain, pains of terminal cancer, in child

birth.

Learning aid:Analgesics

Non-narcotic Narcotic

Aspirin Paracetamol Heroin(e) took morphine in a codeine

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Antimicrobials

Diseases in humans/animals caused byvariety of micro organisms:

They are destroyed/inhibited devp. by antimicrobial drugs:

bacteria

virus

fungi

other pathogens / parasites

anti bacterial drugs

anti viral agents

anti fungal agents

anti parasitic drugs

Antibiotics, Antiseptics and disinfectants - antimicrobial drugs.

(a) Antibiotics

treat infections - have low toxicity for humans and animals.

Originally - they were - chemical substances - produced by micro organisms (bacteria,

fungi, molds) - inhibit / destroy - micro org.

Now - synthetic methods to develop them and also some purely synthetic cmps have been

found to have antibacterial properly - So, modified def: produced wholly/partly by chemical

synthesis - wh/inhibit / destroy micro org. - by intervening in their metabolic process.

19th century - search for chemicals - that adversely affect bacteria - but not host - led Paul

Ehlrich - to discover arsphenamine (salvarsan) - (Arsenic based) - to treat syphilis. It affects

humans too - but bacteria, spirochete more so.

Ehlrich noted Similarity in

StructureSalvarsan Azodyes As As replaced by N N

also, tissues getting coloured by dyes selectively search for - cmps structurally similar

to azodyes and selectively bind to bacteria - led to prontosil, first effective anti -

bacterial agent

Prontosil - in body, converted to - sulphanil amide - which is the actual acting part - led to

a large no. of sulphonamide analogues - called sulpha drugs, collectively..

One of the most effective sulpha drugs: Sulpha pyridine

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mnemonics:

Silver’s son as phine amine Chat spir see phili s- being as - s ally as he s p TV

Salvarsan - azodye - prontosil - sulph anil amide - sulph on amide analogues -sulpha drugs - sulph a pyridine. (connect as a story).

Alexander Fleming - discovered - Penicillium fungus - took 13 yrs. in tr ials penicillin.

Antibiotics - cidal (killing) effect or Static (inhibitory) effect

Bactericidal Bacteriostatic

Penicillin Erythromycin

Aminoglycosides Tetracycline

Ofloxacin Chloram phenicol

Spectrum of action: range of bacteria/micro organisms that are affected by a certain

antibiotic.

Narrow spectrumBroad spectrum

Kill/inhibit a widerange of Gram–+veGram–ve bacteria.

mainly againsteither Gram +veor Gram –ve bac.

Limited spectrum

if active against asingle organism/disease.Eg. Penicillin G

synthetic modification

broad

spectrum

Ampicillin

Amoxycillin.

Penicillin - may be allergic - , needs to be tested for before being administered. (Mfg:

Hindustan antibiotics at Pimpri).

[Note: Gram - staining is a method of differentiating bacterial species into two large groups:

Gram positive & Gram negative. It is based on the chemical/physical properties of the cell

walls. Primarily it detects peptidogly can, which is present in a thick layer in Gram positive

bacteria. A Gram +ve results in a purple/blue colour while a Gram negative results in a pink/

red colour].

Broad spectrum antibiotics:

Chloramphenicol: rapidly from gastro intestinal tract - So, given orally in case

of typhoid, dysentry, acute fever, certain urinary infections,

meningitis and pneumomia.

Vancomycin and ofloxacin

Dysidazirine: supposed to be toxic towards certain strains of cancer cells.

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Learning Aids (Antibiotics)

Amin penny cidegluco of lux Asin side

e - having no - committed sui and in his grave becamese ( ) on .

As all became - they were ... thrown towardse f .

tetra cycles static erchlorin evicol

2G spectrum Raja enicillinAmpicillin/Amoxycillin 3G spectrum Raja

- was given p G - but that didn't help - So,SC ordered which made him .

Of lux Asin chlorine fevicol Vancom

- was tied with and driven to a pany to talk on 3G spectrum.

Daisy - a of was diagnosed withm ji rin - cancer

(b) Antiseptics and disinfectants (kill/prevent growth-micro organisms)

Antiseptics applied to living tissues (wounds, cuts, ulcers, diseased skin surfaces)

- not ingested.

Eg s:

Antiseptic Purpose

Furacine multi purpose

Soframicine multi purpose

Dettol

(terpineol + chloroxylenol)

common wounds, shaving

Bithionol (or Bithional) added to soaps for antiseptic properties.

Tincture of Iodine(2-3% I in R – OH + H O)2 2

applied on wounds.

Iodoform - DO -

Boric acid (aq) Weak antiseptic for eyes.

Disinfectants: applied to inanimate objects like floors, drainage systems.

Egs: same as antiseptic but in varying concentration.

antiseptic

disinfectant.

0.2%

1% phenols

Cl2 (0.2 – 0.4 ppm) (aq)

SO2

in low conc.

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Learning aid:

Dettol

Bithionol

I have woundsWhen I am , I put boric acid in my eyes.bored

terpine oil and a xylo with Chlorine and Alchol.

for bathing

:

:

Antifertility drugs

Antibiotics - long and healthy life - life expectancy doubled presence on food resources,

unemployment, etc. - to counter these - population needs to be planned - family planning -

antifertility drugs - a step in that direction.

Birth control pills - (synthetic estrogen + progesterone derivatives) - both cmps - are

hormones - progesterone - suppresses ovulation - its synthetic versions are more potent.

Nore thin drone - Eg. of progesterone derivative.

ethynylestradiol (nonvestrol) - Eg. of estrogen derivative.

Learning Aid:

P (register one) Nor thin drone neither

Is trojan ethynyl extra di-ol.No Vest roll

war fought with or, its fought with in a .

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CHEMICALS IN FOOD

Introduction

Chemical - added in food for appeal enhancement (like looks)

preservation.

nutritive value.

Colours

Main categories: Flavours & sweeteness

Fat emulsifiers and stabilizing agents (surface chemistry)To increase shelf life

Flour improvers-antistaling agents & bleaches.(or)

AntioxidantsCosmetic purposes

Preservatives

Natrutive value Nutritional supplements minerals,vits,amino acids

Artificial Sweetening Agents

Natural sweeteners (Eg. Sucrose) - high calories - , many avoid it.

Artificial sweetener:

SweetenerSweetness compared

to cane sugar Remarks

Saccharin(Ortho-sulpha benzimide)

550 excreted as such

harmless. Esp. useful for diabetic people.

entirely inert

Aspartame 100

aspartic acid + phenylalanine

dipeptide

its methyl ester

Aspartame

(Unstable at cooking temperature So,

use ltd. to cold foods and soft drinks).

Alitame 2000 high potency (strength) sweetener - more

stable than aspartame - but control ofsweetness is difficult.

Sucrolose 600 Sucrose trichloro derivative - appears

and tastes like sugar - stable at cooking temp.

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Learning aid

Sacch Rin O S B Ia == rtho ulpho enz mide. (O ! SBI)

As per tom Aspartame is sweet

Ali tamed his over - sweet behaviour.

Su Cro lose? weight

Food preservatives (prevent spoilage of food due to microbial growth).

Egs: Salt (table), sugar

Vegetable oils

Sodium Benzoate (C6H

5COONa) - used in ltd. quantity - metabolised in the body

(Metabolism: Your metabolism is the way that chemical processes in your body cause food to

be used in an efficient way, for example to make new cells and to give you energy).

Salts of sorbic acid and propanoic acid

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Antioxidants

Food decomposes by oxidation - Antioxidants (AO) - retard the action of Oxygen on food - reducing

its speed of decomposition food preservation.

They act by virtue of being more reactive towards oxygen than are the materials they are protecting.

Also, reduce rate of involvement of free radicals in ageing process.

Egs :

added to preserve fats in packaged food - by - Oxygen reacting preferably with them.

their addition to butter - increases storage life from months to years.

Sometimes added with citric/ascorbic acids to produce a more active synergetic

effect.

Other Egs”

SO2

Sulphites (Na2SO

3, NaHSO

3, sodium meta bisulphite)

both are used for beer & wine

Sugar syrup

Cut, peeled or dried fruits and vegetables

Prevent / reduce their discolouration

Questions:

Name one AO commonly used to increase the storage life of butter.

Name one AO used in wine and beers.

CLEANSING AGENTS

Introduction

Two types of detergents

Soaps

Synthetic detergents

improve cleansing propertyof water.

by helping in

removal of fats wh/ bind othermaterials to the fabric/skin

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Soaps

Preparation (called saponification):

fat + NaOH (aq) soap.

Chemically, they are Na/K salts of long chain fatty acids, eg. stearic, oleic and palmitic acids.

(esters of fatty acids) hydrolyse NaCl

colloidal

soap precipitated soap

when removed

glycerol left behind

(recovered by F.D.)

K soaps - softer than Na Soaps. - prepared by using KOH instead of NaOH in the above.

Types of soaps

Gen. prep: fats / oils + suitable hydroxide variations by using different raw mat.

Soap types

T o i l e

t

Floating Soap

T r a n s p a r e n t

S h

a v i n

g

ScoutingSoap

Soap powder

L a u n d r y

S o a p c h i p s

Medicated

S o a p G

r a n u l e s

Contain glycerol - to prevent drying

rosin (a gum) is added - formssodium rosinate - lathers well.

better grade fat/oil

excess alkali must be removed

added colour & perfumes

by beating tiny air bubbles

before hardening

by dissolving soap in ethanol(then evaporate the solvent)

scourging agent (abrasive)Eg. powdered pumice/finely divided sand

Buiders: Na CO (or) Na PO ( make soap act rapidly).2 3 3 4

dried miniaturesoap bubbles

Contain Sodium rosinate

Sodium sillicate

Sodium carbonateBorax

by running a thin sheet ofmelted soap on a coolcylinder - scrap off in places

substances ofmedicinal value

(and deodorants)are added.

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Why do soaps not work in Hard water?

Hard water (HW) contains 2 2and .Ca Mg When soap is dissolved, the following rxn

takes place:

17 35 2 17 35 2Insoluble Calcium Stearate2 2C H COONa CaCl NaCl C H COO Ca

An insoluble cmp. ppt. out - separate as scum - useless as cleaning agent - further - sticks

to clothes as a gummy mass.

Thats why hair washed with HW - looks dull.

Thats why dye - doesn’t absorb evenly on cloth washed in hard water.

Synthetic detergents

all properties of soap - but don’t contain soap - can be used in hard water as well and even in ice

cold water.

Non-ionic CationicAnionic

Anionic detergents (AD)

Sodium salts of sulphonated long chain alcohols or HC.

Prep: long chain alcohols2 4

Conc.

H SO Alkyl Hydrogen Sulphate

Alkyl benzene sulphonic acid NaOH

NaOH

Anionic detergent.

Anionic part - involved in cleansing action.

Use : household work, toothpastes.

Cationic detergents (CD)

quarternary ammonium salts of amines with 3

CH COO , Cl , Br as anions

Cationic part: long HC chain and on N.

The following CD is used in hair conditioners:

Have germicidal properties and are expensive

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Non-ionic detergents (NID)

No ions

An example:

Use: Liquid dishwashing

Mechanism of action: Same as soaps. (ie. by micelle formation)

Problem w/ detergents

if HC part - highly branched bacteria can’t degrade it leads to their accumulation -

they reach water bodies as such cause foaming in water bodies and thus pollutes them.

Solution: branching of HC is kept at a minimum.

Learning Aid:

Soap : using Na/K saltsSteer palm oil

AD: Long chain alcohol/HC (sulphonated) Na salts.

CD : Quaternary ammonium salts of Amines with as anions.A B C

END NOTE

Chemistry is essentially the study of materials and the development of new materials for the betterment of humanity. A drug is a chemical agent, which affects human metabolism and provides cure from ailment. If taken

in doses higher than recommended, these may have poisonous effect. Use of chemicals for therapeutic effect is

called chemotherapy. Drugs usually interact with biological macromolecules such as carbohydrates, proteins,

lipids and nucleic acids. These are called target molecules. Drugs are designed to interact with specific targets

so that these have the least chance of affecting other targets. This minimises the side effects and localises the

action of the drug. Drug chemistry centres around arresting microbes/destroying microbes, preventing the

body from various infectious diseases, releasing mental stress, etc. Thus, drugs like analgesics, antibiotics,

antiseptics, disinfectants, antacids and tranquilizers are used for specific purpose. To check the population

explosion, antifertility drugs have also become prominent in our life.

Food additives such as preservatives, sweetening agents, flavours, antioxidants, edible colours and nutritionalsupplements are added to the food to make it attractive, palatable and add nutritive value. Preservatives are

added to the food to prevent spoilage due to microbial growth. Artificial sweeteners are used by those who

need to check the calorie intake or are diabetic and want to avoid taking sucrose.

These days, detergents are much in vogue and get preference over soaps because they work even in hard

water. Synthetic detergents are classified into three main categories, namely: anionic, cationic and non-ionic,

and each category has its specific uses. Detergents with str aight chain of hydrocarbons are preferred

over branched chain as the latter are non-biodegradable and consequently cause environmental pollution.

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Chemistry in Everyday Life