e z > ^ / e - classmate · 2017-03-31 · ' e z > ^ / e Á Á Á x o u u Ç x } u z u ]...

GENERAL SCIENCE

www.classmateacademy.com

Chemistry : Egyptian word Chemeo (Black)


Father of Modern Chemistry : Lavoisier

STATES OF MATTER

Matter• Anything which has mass and occupies a space.

Types of Matter :(a)Physical Composition (b)Chemical CompositionTHE SOLID STATE• The have a definite shape, distinct boundaries and fixed volumes, that is, have

negligible compressibility. they are rigid.

THE LIQUID STATE• Liquids have no fixed shape but have a fixed volume.• Liquids have no fixed shape but have a fixed volume.• They take up the shape of the container in which they are kept.• Liquids flow and change shape, so they are not rigid (Fluid)

THE GASEOUS STATE• Gases are highly compressible as compared to solids and liquids.• In the gaseous state, the particles move about randomly at high speed. Due to

this random movement, the particles hit each other and also the walls of thecontainer.


• The forces of attraction between the particles are maximum in solids, intermediatein liquids and minimum in gases.

• The spaces in between the constituent particles and kinetic energy of the particles areminimum in the case of solids, intermediate in liquids and maximum in gases.

• The arrangement of particles is most ordered in the case of solids, in the case of liquidslayers of particles can slip and slide over each other while for gases, there is no order,particles just move about randomly.

• The states of matter are inter-convertible. The state of matter can be changed by changingtemperature or pressure.temperature or pressure.

• Sublimation is the change of gaseous state directly to solid state without going throughliquid state, and vice versa.

• Boiling is a bulk phenomenon. Particles from the bulk (whole) of the liquid change intovapor state.

• Evaporation is a surface phenomenon. Particles from the surface gain enough energy toovercome the forces of attraction present in the liquid and change into the vapor state.


• The amount of heat energy that is required to change 1 kg of a solid intoliquid at atmospheric pressure at its melting point is known as the latentheat of fusion.

• The State of Matter depends on Pressure and Temperature

Sublimation-------Eg: Dry ice


• The rate of evaporation depends upon the surface area exposed to theatmosphere, the temperature, the humidity and the wind speed.

• Evaporation causes cooling.

• Latent heat of vaporization is the heat energy required to change 1 kg of aliquid to gas at atmospheric pressure at its boiling point.

• Latent heat of fusion is the amount of heat energy required to change 1 kg ofsolid into liquid at its melting point.


• Vapor pressure or equilibrium vapour pressure is defined as the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid or liquid) at a given temperature in a closed system.

• Evaporation is a surface phenomenon : Particles from the surface gain enough energy to overcome the forces of attraction present in the liquid and change into the vapor state.

• The equilibrium vapor pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A


relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapor pressure at normal temperatures is often referred to as volatile.

Osmosis :


Reverse osmosis :


Matter

Based on chemical composition :

Element : The most fundamental substance which cannot be further divided in to any more parts by any process .It is the fundamental matter which is made from identical atoms and cannot be decomposed into any other .

The different elements are now arranged in a Periodic table.

Compound: It is pure substance which is formed by the chemical combination of


Compound: It is pure substance which is formed by the chemical combination of two or more elements in a definite ratio. The Physical and Chemical Properties of the compound are different from its constituent elements.

Mixture :It is an impure substance formed by combination of two or more pure elements by the means of a physical process and it doesn’t have any definite ratio.

The components of a mixture can be separated by physical process.

MIXTURE

Mixtures are constituted by more than one kind of pure form of matter, known as asubstance. Methods of Separation

• Hand Picking• Threshing• The process that is used to separate grain from stalks etc. is threshing.

• WinnowingWinnowing is used to separate heavier and lighter components of a mixture by

wind or by blowing air.

• SievingSieving allows the fine flour particles to pass through the hoes of the sieve

while the bigger impurities remain on the sieve.


ATOMS AND MOLECULES

• An atom is the smallest particle of the element that can exist independently and retainall its chemical properties.

• A molecule is the smallest particle of an element or a compound capable ofindependent existence under ordinary conditions. It shows all the properties of thesubstance.


• A chemical formula of a compound shows its constituent elements and thenumber of atoms of each combining element.

• Clusters of atoms that act as an ion are called polyatomic ions. They carry a fixedcharge on them.

• The chemical formula of a molecular compound is determined by the valency ofeach element.

• The Avogadro constant 6.022 × 1023 is defined as the number of atoms in exactly• The Avogadro constant 6.022 × 1023 is defined as the number of atoms in exactly12 g of carbon-12.

• The mole is the amount of substance that contains the same number of particles(atoms/ ions/ molecules/ formula units etc.) as there are atoms in exactly 12 g ofcarbon-12.


STRUCTURE OF THE ATOMDaltons theory :


• In chemistry the chemical symbols of the elements were developed and propounded by Berzelius in 1811

• Credit for the discovery of electron and proton goes to J.J. Thomson andE.Goldstein, respectively.

• J.J. Thomson proposed that electrons are embedded in a positive sphere.


• Cathode ray experiment and fixed e/m ratio.

• Discovery of electron

Mulliken Oil Drop Experiment :

• Charge always a multiple of 1.6022 x 10-19 Coulomb


• Rutherford’s alpha-particle scattering experiment led to the discovery of the atomicnucleus.

• Rutherford’s model of the atom proposed that a very tiny nucleus is present inside theatom and electrons revolve around this nucleus. The stability of the atom could not beexplained by this model.


• Neils Bohr’s model of the atom was more successful. He proposed that electrons aredistributed in different shells with discrete energy around the nucleus. If the atomic shellsare complete, then the atom will be stable and less reactive.


Electron:

• Charge: It is a negatively charged particle.• Magnitude of charge: Charge of electron is 1.6022 x 10-19 Coulomb.• Mass of electron: Mass of electron is 0.000548597 a.m.u. or 9.1 x 10-31 kg.• Location in the atom: Electrons revolve around the nucleus of atom in different circular orbits.• Symbol of electron: Electron is represented by "e"

Proton:


Proton:

Charge: Proton is a positively charged particle.Magnitude of charge: Charge of proton is 1.6022 x 10-19 coulomb.Mass of proton: Mass of proton is 1.0072766 a.m.u. or 1.6726 x 10-27 kg.Comparative mass: Proton is 1837 times heavier than an electron.Position in atom: Protons are present in the nucleus of atom.

• J. Chadwick discovered presence of neutrons in the nucleus of an atom. So, thethree sub-atomic particles of an atom are: (i) electrons, (ii) protons and (iii)neutrons. Electrons are negatively charged, protons are positively charged andneutrons have no charges. The mass of an electron is about 1 2000 times themass of an hydrogen atom. The mass of a proton and a neutron is taken as oneunit each.

Charge: It is a neutral particle because it has no charge.Mass of neutron: . Mass of neutron is 1.0086654 a.m.u. or 1.6749 x 10-27 kg.Compartive mass: Neutron is 1842 times heavier than an electron.Location in the atom: Neutrons are present in the nucleus of an atom.Location in the atom: Neutrons are present in the nucleus of an atom.


• Valency is the combining capacity of an atom.

• The atomic number of an element is the same as the number of protons in thenucleus of its atom.

• The mass number of an atom is equal to the number of nucleons in its nucleus.

• Isotopes are atoms of the same element, which have different mass numbers.

• Isobars are atoms having the same mass number but different atomic numbers.


• Elements are defined by the number of protons they possess.

Medvedev Periodic table based on Atomic Weights :


Modern Periodic Table : Mosley Law


Radioactivity :

• Henry Becquerel , in 1896 discovered radioactivity by observing uranium compounds.

• 1902 ,madam Curie and Pierre curie invented Radium .

• Radioactive elements split into smaller fragments by the process of spontaneous .

• Disintegration of the nuclei, and emit the following rays called

• Alpha-Particle ,Beta particles and Gamma emissions.


• Alpha-Particle ,Beta particles and Gamma emissions.

Alpha Emissions Beta emissions Gamma Emissions

He(doubly charged ) Fast moving electrons Electromagnetic rays

1/10 of velocity of light In between Alpha and Gamma

light

Maximum Ionizing power

Comparatively less Electrically neutral

Least penetratingpower

In between Alpha and Gamma

It has the largest penetrating power

Half Life period of a radio active Element :

• Every element has its own half life and thus different radioactive elements have different half lives.

• C-14(5730),U-238(4.468 billion yrs)

• Units : Curie(3.7x10 10 disintegration/second),Rutherford (10 6),Becquerel (1)Geiger Muller Counter is used to measure radioactivity.

Practical Uses :


Practical Uses :Pipe leakage ,Cancer Treatment(Co-60,Ra),Unwanted residue in blood (Sodium),

Bone diseases(radio phosphorous) Thyroid(radio iodine),Anaemia, Tuberclosis (radio-iron), Plant Mutation,

Metals and Non-metals

PHYSICAL PROPERTIES of METALS:

• Metals, in their pure state, have a shining surface. This property is calledmetallic luster.

• Iron, Copper, Aluminum, magnesium, sodium, lead, zinc

• Metals are generally hard. The hardness varies from metal to metal.

• Metals can be beaten into thin sheets. This property is called malleability.

• The ability of metals to be drawn into thin wires is called ductility. Gold is themost ductile metal.

• Metals are good conductors of heat and have high melting points. Eg: bestconductors of heat are silver and copper. (Exception: Lead and mercury arecomparatively poor conductors of heat)

• METALS are Hard, lustrous, malleable, ductile, sonorous and goodconductors of heat and electricity.


Exception:

• All metals except mercury exist as solids at room temperature.

• Gallium and caesium have very low melting points. These two metals will melt ifyou keep them on your palm.

• Iodine is a non-metal but it is lustrous.

• Carbon is a non-metal that can exist in different forms. Each form is called anallotrope. Diamond, an allotrope of carbon, is the hardest natural substanceallotrope. Diamond, an allotrope of carbon, is the hardest natural substanceknown and has a very high melting and boiling point. Graphite, anotherallotrope of carbon, is a conductor of electricity.

• Alkali metals (lithium, sodium, potassium) are so soft that they can be cut with aknife. They have low densities and low melting points.

• All bases do not dissolve in water. An alkali is a base that dissolves in water. Theyare soapy to touch, bitter and corrosive. Never taste or touch them as they maycause harm.


Most abundant element on earth crust

Oxygen

Most abundant metal on earth Aluminum

Lightest element Hydrogen

Heaviest element Osmium

Lightest Metal Lithium


Lightest Metal Lithium

Liquid Metal Mercury

Liquid Non-metal Bromine

Non-metal best conductor ofelectricity

Graphite

Metal best conductor of electricity

Silver

Metal second best conductor Copper

Most malleable metal Gold

Monoatomic elements Inert Gases

Most abundant element in Oxygen


Most abundant element in human body

Oxygen

Element kept in kerosene Sodium

• Pure substances can be elements or compounds. An element is aform of matter that cannot be broken down by chemical reactionsinto simpler substances.

• A compound is a substance composed of two or more differenttypes of elements, chemically combined in a fixed proportion.

• Properties of a compound are different from its constituentelements, whereas a mixture shows the properties of itsconstituting elements or compounds.constituting elements or compounds.


Modern Periodic Table : Mosley Law


Electronic Theory of Valency :


PERIODIC CLASSIFICATION OF ELEMENTS

• Valency : The valency of an element is determined by the number of valenceelectrons present in the outermost shell of its atom.

• Atomic size: The term atomic size refers to the radius of an atom.

• The atomic size may be visualized as the distance between the centre of thenucleus and the outermost shell of an isolated atom.

• Atomic radius decreases in moving from left to right along a period

• Atomic size increases down the group

• Electronegativity/ Electron Affinity increases across a period and decrease down agroup.

Metallic and Non-metallic Properties• The metals like Na and Mg are towards the left-hand side of the Periodic Table

• The non-metals like sulphur and chlorine are found on the right-hand side


The of Ionic Compounds:


Properties of Ionic Compounds

•Physical nature: Ionic compounds are solids and are somewhat hard because of the strongforce of attraction between the positive and negative ions.

These compounds are generally brittle and break into pieces when pressure is applied.

• Melting and Boiling points: Ionic compounds have high melting and boiling points .

•Solubility: Electrovalent compounds are generally soluble in water and insoluble in solventssuch as kerosene, petrol, etc.

•Conduction of Electricity:Ionic compounds in the solid state do not conduct electricity because movement of ions inIonic compounds in the solid state do not conduct electricity because movement of ions inthe solid is not possible due to their rigid structure.But ionic compounds conduct electricity in the molten state.This is possible in the molten state since the electrostatic forces of attraction between theoppositely charged ions are overcome due to the heat.Thus, the ions move freely and conduct electricity.


Covalent Compound :


Properties of Covalent Molecular Compounds.• Low melting points and boiling points. ...• Low enthalpies of fusion and vaporization These properties are

usually one or two orders of magnitude smaller than they are for ionic compounds.

• Soft or brittle solid forms. ...• Poor electrical and thermal conductivity


Solution Suspension ColloidHomogenous Heterogeneous HeterogeneousSize 10-9 m Size 10-7 m Size 10-9 -10-7 mParticles are so small they cannot be seen with naked eye. No filtration

Particles can be seen with naked eye . Filtration can be done

Particles cannot be seen with naked eye . Filtration cannot be done


filtrationSolution is stable, particles do not settle down after some time

Suspension is unstable particles settle down after some times

Colloid is also stable the particles don settle down after some time

No scattering Shows scattering Shows scattering

SOLUTIONA solution is a homogeneous mixture of two or more substances. Eg: Soda Water

Properties of a solution:• A solution is a homogeneous mixture.

• Solute and Solvent.• Water is universal solvent• Saturated Solution and Unsaturated Solution.

• The particles of a solution are smaller than 1 nm (10-9 m) in diameter. So, theycannot be seen by naked eyes.

• Because of very small particle size, they do not scatter a beam of light passingthrough the solution. So, the path of light is not visible in a solution.

• The solute particles cannot be separated from the mixture by the process offiltration. The solute particles do not settle down when left undisturbed, that is, asolution is stable.


Types of Solution Examples

Solution of Gas in Gas Air, Mixture of Gases

Gas in liquid Oxygen in waterCarbon dioxide in water

Liquid in liquid Alcoholic beverages

Solid in liquid Sugar in water,Sea Water


Solid in liquid Sugar in water,Sea Water

Gas in solids Hydrogen over Palladium

Liquid in Solid Mercury in Gold Forming an Amalgam

Solid in Solid Alloys,

Process of Fractional Distillation : By this method a mixture of Liquids of which have narrow boiling point differences are separated . Eg Petroleum .

Process of Sublimation : By this process two or more solids are separated where in one of them changes its state to directly vapour when heated .


Alloys: Alloys are homogeneous mixtures of metals or metals and non metalsand cannot be separated into their components by physical methods. But still,an alloy is considered as a mixture because it shows the properties of itsconstituents and can have variable composition.For example, brass is a mixture of approximately 30% zinc and 70% copper.

• Alloying is a very good method of improving the properties of a metal. Wecan get the desired properties by this method.


can get the desired properties by this method.

• Pure gold, known as 24 carat gold, is very soft. It is, therefore, not suitable formaking Jewelry. It is alloyed with either silver or copper to make it hard.Generally, in India, 22 carat gold is used for making ornaments. It means that22 parts of pure gold is alloyed with 2 parts of either copper or silver.

• Pure iron is very soft and stretches very easily when it is hotSteel= Iron + 0.05% C(0.002-2.1%)

• Iron + Ni + Cr = Stainless Steel - Hard and does not rust.

• If one of the metals is mercury, then the alloy is known as amalgam.

• The electrical conductivity and melting point of an alloy is less thanthat of pure metals.

• Brass = Cu + Zn


• Bronze = Cu + Sn (tin)

• Solder = Pb + Sn = Lead + Tin. Solder has low melting point.

• Nichrome - Ni,Fe,Cr,Mn etc Electric heater ,Good quality electricwires.

Aluminium Alloys: Uses:

Magnelium Mg(2%),Al(95%),Cu-Fe(2-3%) Aircraft parts

Duralumin Al(94%),Cu(4%),Mg(0.5%),Zn(4.5%),Mn(0.5%)

Pressure cooker and aircraft parts

Aluminium Bronze Al-105,Cu-90% Utensils,coins,ornaments etc.

Steel

Aluminium Bronze Cu(90%),Al(10%) Kitchen Utensils


Stainless Steel Chromium(10.5%),carbon,Nickel,Molybdenum.

Safety vaults,ballbearings

Invar Nickel (36%),Iron(64%) Pendulum watches

Tungsten Steel Tungsten(10-20%),Iron Spring magnet saws

Copper Alloys: Uses:

Brass Cu-70%,Zn-30 % Machine parts,utensils

Bronze Cu-90%,Sn-10% Utensils,idols.

Artificial Gold Cu-90%,Al-10% Idols,ornaments

Coin metals Cu-95%,Sn-4%,P-1% Coins

Gun Metal Cu-88%,Sn-10%,Zn-2% Gun,Pistol

Bell Metals Cu-80%,Sn-20% Bells

Constanton Cu-60%,Ni-40% Wires


Constanton Cu-60%,Ni-40% Wires

Monal Metal Cu-28%,Fe-2%,Ni-70% Making idols

German Silver Cu-50%,Zn-35%,Ni-15% Utensils

Dutch Metal Cu-80%,Zn-20% machines

SUSPENSION

• Dispersion : If the constituent particles of a substance is scattered aroundthe another substance then it is called dispersion.

Properties of a Suspension• Suspension is a heterogeneous mixture.

• The particles of a suspension can be seen by the naked eye.

• The particles of a suspension scatter a beam of light passing through it and• The particles of a suspension scatter a beam of light passing through it andmake its path visible.

• The solute particles settle down when a suspension is left undisturbed, that is,a suspension is unstable. They can be separated from the mixture by theprocess of filtration.


• Sedimentation , Decantation and Filtration• When the heavier component in a mixture settles after water is added to it, the

process is called sedimentation.

• When the water (along with the dust ) is removed, the process is calleddecantation.

• The same principle is used for separating a mixture of two liquids that do not mixwith each other. For example, oil and water from their mixture can be separated bythis process.


The component that forms the top layer can then be separated bydecantation.

• After preparing tea, what do you do to remove the tea leaves? Try decantation. Ithelps a little. But, do you still get a few leaves in your tea ? Now, pour the teathrough a strainer. This process is called filtration.

COLLOIDAL SOLUTIONProperties of a colloid• A colloid is a heterogeneous mixture.

• The size of particles of a colloid is too small to be individually seen bynaked eyes.

• Colloids are big enough to scatter a beam of light passing through itand make its path visible.

• They do not settle down when left undisturbed, that is, a colloid is• They do not settle down when left undisturbed, that is, a colloid isquite stable.

Tyndall effect


Tyndall Effect in Nature :


Chemical Reactions and Equations

TYPES OF CHEMICAL REACTIONS :

• Combination Reaction

• Decomposition Reaction

• Displacement Reaction

• Double Displacement Reaction• Double Displacement Reaction

• Oxidation and Reduction


Chemical Reactions based on Energy :

• Exothermic Reactions.eg a candle flame

• Endothermic Reactions.eg evaporation of water

Combination Reaction


• During a chemical reaction, the sum of the masses of the reactants andproducts remains unchanged. This is known as the Law of Conservationof Mass.

• In a pure chemical compound, elements are always present in a definiteproportion by mass. This is known as the Law of Definite Proportions.


Decomposition Reaction


Displacement Reaction


Double Displacement Reaction

Oxidation

Zn → Zn2+ + 2 e


Reduction

Cu2+ + 2 e− → Cu

Zn → Zn2+ + 2 e

(corrosion)4Fe + 3O2 → 2Fe2O3

(Photosynthesis)C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Volta was the inventor of the voltaic pile, the first electrical battery

Daniel cell


Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)


Nickel–cadmium battery (NiCd battery or NiCad battery) is a type of rechargeablebattery using nickel oxide .

NickelHydride, Lithium batteries are disposable (primary) batteries that have lithium metal.

The Reactivity Series


Aqua regia, (Latin for ‘royal water’) is a freshly prepared mixture ofconcentrated hydrochloric acid and concentrated nitric acid in the ratio of3:1. It can dissolve gold, even though neither of these acids can do soalone.Aqua regia is a highly corrosive, fuming liquid.It is one of the few reagents that is able to dissolve Gold and Platinum.

Metals reaction with Solutions of other Metal Salts


CHEMICAL PROPERTIES of METALS:

Metals combine with oxygen to form metal oxides.

Metal oxides are basic in nature.Amphoteric oxides : Show both acidic as well as basic behavior. (Eg: Aluminium oxide, Amphoteric oxides : Show both acidic as well as basic behavior. (Eg: Aluminium oxide, zinc oxide, etc.)


Metal oxides are insoluble in water but some of these dissolve in water to form alkalis.

Metals do not react with oxygen at the same rate.

Potassium and Sodium react so vigorously that they catch fire if kept in theopen, so they are kept immersed in kerosene oil.

The surfaces of metals such as Magnesium, Aluminum, Zinc, Lead, etc., arecovered with a thin layer of oxide. The protective oxide layer prevents themetal from further oxidation.

Silver and Gold do not react with oxygen even at high temperatures.


Metals reaction with Water

Metals reaction with Acids

The reactivity decreases in the order Mg > Al > Zn > Fe.


Corrosion Eg:• Rusting of iron, • Black coating on silver, • Green coating on copper

Rancidity

Eg: When fats and oils are oxidized, they become rancid and their smell and taste change.taste change.

To prevent oxidation(antioxidants) are added to foods containing fats and oil.

Chips manufacturers usually flush bags of chips with gas such as nitrogen to prevent the chips from getting oxidized.


CORROSIONPrevention of Corrosion• The rusting of iron can be prevented by painting, oiling, greasing, galvanizing,

chrome plating, anodizing or making alloys.

• Galvanization is a method of protecting steel and iron from rusting by coatingthem with a thin layer of zinc.

• Anodising is a process of forming a thick oxide layer of aluminium. Aluminiumdevelops a thin oxide layer when exposed to air. This aluminium oxide coat makesit resistant to further corrosion. The resistance can be improved further by makingit resistant to further corrosion. The resistance can be improved further by makingthe oxide layer thicker. During anodising, a clean aluminium article is made theanode and is electrolysed with dilute sulphuric acid. The oxygen gas evolved at theanode reacts with aluminium to make a thicker protective oxide layer. This oxidelayer can be dyed easily to give aluminium articles an attractive finish.


Acids, Bases and Salts

• Curd, lemon juice, orange juice and vinegar taste sour. These substances taste sour because they contain acids. The chemical nature of such substances is acidic.

• What about baking soda. It is better in taste. If you rub its solution between fingers, it feels soapy. Substances like these which are bitter in taste and feel soapy on touching are known as bases. The nature of such substances is said to be basic.such substances is said to be basic.

• An acid is a substance which has a replaceable Hydrogen.

• How to detect acids and bases : Special type of substances are used to test whether a substance is acidic or basic. These substances are known as Indicators.

• Turmeric , litmus, china rose petals(Gudhal), etc., are some of the naturally occurring indicators.


Some examples of naturally occurring acids :

Name of base Found in Calcium hydroxide Lime waterAmmonium hydroxide Window cleanerSodium hydroxide/ Potassium hydroxide Soap Magnesium hydroxide Milk of magnesia

Formic acid


Litmus : A natural dye The most commonly used natural indicator is litmus. It is extracted

from lichens it has a mauve (purple) color in distilled water.

• Generally it is available as red and blue litmus paper.• Litmus paper : Acid : Blue to Red (Base : Red to Blue).

The solutions which do not change the colour of either red or blue litmus are known as neutral solutions. These substances are neither acidic nor basic.

Turmeric is another natural IndicatorTurmeric stain on white shirt is turned to red when it is washed with Turmeric stain on white shirt is turned to red when it is washed with

soap. It is because the soap solution is basic.

China Rose as IndicatorChina rose indicator turns acidic solution to dark pink (magenta) and

basic solutions to green.

Phenolphthalein solution : Remains colorless (When added to acid)Turns Pink (When added to base).

Methyl orange solution : Orange to Yellow (when added to base)Orange to Pink (when added to acid).


The reaction between an acid and a base is known as neutralization.Salt and water are produced in this process with the evolution of heat.

Neutralization in Everyday Life:Indigestion• Our stomach contains hydrochloric acid. It helps us to digest food. But too much of acid

in the stomach causes indigestion. Sometimes indigestion is painful. To relieveindigestion, we take an antacid such as milk of magnesia, which contains magnesiumhydroxide. It neutralizes the effect of excessive acid.

Ant bite• When an ant bites, it injects the acidic liquid (formic acid) into the skin. The effect of the

acid can be neutralized by rubbing moist baking soda (sodium hydrogen carbonate).acid can be neutralized by rubbing moist baking soda (sodium hydrogen carbonate).

Soil treatment• Excessive use of chemical fertilizers makes the soil acidic. Plants do not grow well when

the soil is either too acidic or too basic.• When the soil is too acidic, it is treated with bases like quick lime (calcium oxide). Or

slaked lime (calcium hydroxide).• If the soil is basic, organic matter is added to it. Organic matter releases acids which

neutralizes the basic nature of the soil.


Factory Waste:

• The waste of my factories contain acids. If they are allowed to flow into the waterbodies, the acids will kill fish and other organisms.

• The factory wastes are, therefore, neutralized by adding basic substances.

• Oxalic Acid used in Photography, colouration and printing of the cloths, in thebleaching of leather ,in removing the ink spot from the cloth.


HOW STRONG ARE ACID OR BASE SOLUTIONS: pH scale


PH in Everyday Life:

• Human body: PH range of 7.0 to 7.8.• Acid rain: PH of rain water is less than 5.6

• The atmosphere of Venus(Planet) is made up of thick white and yellowish clouds of sulphuric acid.

• PH change as the cause of tooth decay

• Tooth decay starts when the PH of the mouth is lower than 5.5.

• Tooth enamel, made up of calcium phosphate is the hardest substance in the body. It does not dissolve in water, but is corroded when the PH in the mouth is below 5.5.

• Bacteria present in the mouth produce acids by degradation of sugar and food particles remaining in the mouth after eating.

• The best way to prevent this is to clean the mouth after eating food.


Acid and bases reactions with Metals :

SALTS : Salts are used for making many compounds.

Common salt is used for making compounds like sodium hydroxide, bakingsoda, washingsoda, bleaching powder.

Sodium hydroxide :


Bleaching powder

Bleaching powder is used :

• For bleaching cotton and linen in the textile industry, for bleaching woodpulp in paper factories and for bleaching washed clothes in laundry;

• As an Oxidizing agent in many chemical industries; and

• For disinfecting drinking water to make it free of germs.

Baking sodaThe chemical name of the compound is sodium hydrogen carbonate (NaHCO3).


Uses of sodium hydrogen carbonate (NaHCO3)

• For making baking powder, which is a mixture of baking soda (sodium hydrogencarbonate) and a mild edible acid such as tartaric acid. When baking powder is heatedor mixed in water, the following reaction takes place –

Carbon dioxide produced during the reaction causes bread or cake to rise making them soft and spongy.

Sodium hydrogen carbonate is also an ingredient in antacids. Being alkaline, it neutralizes excess acid in the stomach and provides relief.

• It is also used in soda-acid fire extinguishers.


Washing soda

Uses of washing soda :

• Sodium carbonate (washing soda) is used in glass, soap and paper industries.

• It is used in the manufacture of sodium compounds such as borax.

• Sodium carbonate can be used as a cleaning agent for domestic purposes.

• It is used for removing permanent hardness of water.


OCCURRENCE OF METALS

The earth’s crust is the major source of metals.Seawater also contains some soluble salts such as sodium chloride, magnesium chloride, etc.

Extraction of Metals

• Gold, silver, platinum and copper are found in the free state.

• (Zn, Fe, Pb, etc.) are moderately reactive. They are found in the earth’s crustmainly as oxides, sulphides or carbonates.mainly as oxides, sulphides or carbonates.

• (K, Na, Ca, Mg and Al) are so reactive that they are never found in nature asfree elements.


Enrichment of Ores

Gangue : Ores mined from the earth are usually contaminated with large amounts ofimpurities such as soil, sand, etc. called gangue

The impurities must be removed from the ore prior to the extraction of the metal.

Extracting Metals Low in the Activity SeriesMetals low in the activity series are very unreactive. The oxides of these metals can bereduced to metals by heating alone.reduced to metals by heating alone.


Extracting Metals in the Middle of the Activity Series

• It is easier to obtain a metal from its oxide, as compared to its sulphides and carbonates.

• Roasting: The sulphide ores are converted into oxides by heating strongly in the presence of excess air.

• Calcination: The carbonate ores are changed into oxides by heating strongly in limited air.


Extracting Metals towards the Top of the Activity Series• These metals are obtained by electrolytic reduction.• Eg: sodium, magnesium and calcium

Refining of Metals• The metals produced by various reduction processes described above are not

very pure.very pure.• The most widely used method for refining impure metals is electrolytic refining.


Volta was the inventor of the voltaic pile, the first electrical battery

Daniel cell


Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)

Electrolytic Refining: Many metals, such as copper, zinc, tin, nickel, silver, gold, etc., are refined electrolytically.


Organic Chemistry :

Earlier it meant chemistry of substances found in living substances .

IUPAC : Chemistry of Carbon and its compounds except carbon,carbonate,bicarbonate,metallic cyanamide carbon monoxide, carbon dioxide.

1828-Fredrick Wohler made first Organic compound Urea.


1828-Fredrick Wohler made first Organic compound Urea.

CARBON AND ITS COMPOUNDSCarbon has the unique ability to form bonds with other atoms of carbon, giving riseto large molecules. This property is called Catenation.

Allotropes of carbonThe element carbon occurs in different forms in nature with widely varying physicalproperties. Both diamond and graphite are formed by carbon atoms, the differencelies in the manner in which the carbon atoms are bonded to one another. Indiamond, each carbon atom is bonded to four other carbon atoms forming a rigidthree-dimensional structure. In graphite, each carbon atom is bonded to threeother carbon atoms in the same plane giving a hexagonal array.One of these bonds is a double-bond, and thus the valency of carbon is satisfied.One of these bonds is a double-bond, and thus the valency of carbon is satisfied.Graphite structure is formed by the hexagonal arrays being placed in layers oneabove the other.


Formation of coal and petroleum

• Coal and petroleum have been formed from biomass which has beensubjected to various biological and geological processes. Coal is the remainsof trees, ferns, and other plants that lived millions of years ago. These werecrushed into the earth, perhaps by earthquakes or volcanic eruptions. Theywere pressed down by layers of earth and rock. They slowly decayed intocoal.

• Oil and gas are the remains of millions of tiny plants and animals that lived inthe sea. When they died, their bodies sank to the sea bed and were coveredthe sea. When they died, their bodies sank to the sea bed and were coveredby silt. Bacteria attacked the dead remains, turning them into oil and gasunder the high pressures they were being subjected to. Meanwhile, the siltwas slowly compressed into rock. The oil and gas seeped into the porousparts of the rock, and got trapped like water in a sponge.


Combustion : Burning is a high-temperature exothermic redox chemical reaction between a fuel and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke.

The Three Conditions for Combustion :

• A combustible Substance• Supporter of Combustion


• Supporter of Combustion• Sufficient heating to reach a temperature where combustion starts.Spontaneous Combustion : phosphorus self-ignites at room temperature without the application of heat.

Why do substances burn with or without a flame?

• Coal or charcoal in an ‘angithi’ sometimes just glows red and givesout heat without a flame. This is because a flame is only producedwhen gaseous substances burn. When wood or charcoal is ignited,the volatile substances present vapourise and burn with a flame inthe beginning.

• A luminous flame is seen when the atoms of the gaseous substanceare heated and start to glow. The color produced by each element isare heated and start to glow. The color produced by each element isa characteristic property of that element.


• The incomplete combustion gives soot which is carbon.

• Complete Combustion

• Fuels:• Coal Gas : Hydrogen

gas(55%),Methane(30%),Carbondioxide(4%),


gas(55%),Methane(30%),Carbondioxide(4%),Unsaturated Hydrocarbon(3%).

• Water gas : Carbon Monoxide, Hydrogen,Carbondioxide .

• Producer gas : Carbonmonoxide, Nitrogen,Carbondioxide.

• Natural Gas : Methane,carbon dioxide,nitrogen,hydrogensulfide,ethane, propane, butanes, pentanes(Processed)

Bio Gas Plant :

• Bio Gas : methane, hydrogen and carbon monoxide


Petrol : Obtained by Fractional distillation of Petroleum ,clean fuel .

Diesel : Obtained from fractional distillation of Petroleum.

Cheaper than petrol toxic gases like sulphur dioxide are evolved.

ULSD : Pure form of diesel low on sulphur used in Europe.

Green Diesel : Euro -4 Standard, best diesel .


Green Diesel : Euro -4 Standard, best diesel .

Gashol : Petrol (10%) and Alcohol (90%). First used in Brazil.

Octane Number/Octane rating : The air-fuel mixture is heated due to being compressedand is then triggered to burn rapidly by the spark plug and ignition system. If it is heated or compressed too much, then it will explode when triggered.

Engine Knocking .

Standard: (Iso –Octane and Heptane )

The Higher the octane number the better the fuel.Tetra ethyl Lead was added to boost the octane number .

Cetane numbers is Ideal for Diesel Engines.


Cetane numbers is Ideal for Diesel Engines.

Catalytic converter :

Reduction of nitrogen oxides to nitrogen and oxygen: 2NOx → xO2 + N2Oxidation of carbon monoxide to carbon dioxide: 2CO + O2 → 2CO2Oxidation of unburnt hydrocarbons (HC) to carbon dioxide and water: CxH2x+2 + [(3x+1)/2]O2 → xCO2 + (x+1)H2O.

platinum, palladium, rhodium, and gold

FABRICS : Cotton, Wool, Silk or Synthetic

• Fabrics are made up of yarn and yarns are further made up of fibers.• The fibers of some fabrics such as cotton, jute, silk and wool are obtained from plants

and animals there are called Natural fibers.• Fibers are also made from chemical substances, which are not obtained from plant or

animal sources. These are called Synthetic fibers. Some examples of synthetic fibers arepolyester, nylon and acrylic.

COTTON :

• Cotton plants are usually grown at places having black soil and warm climate.

• The fruits of the cotton plant are called cotton bolls. After maturing, the bolls burstopen and the seeds covered with cotton fibers can be seen.

• From these bolls cotton is usually picked by hand. Fibers are then separated from theseeds by combing this process is called ginning of the cotton.


Spinning Cotton Yarn

• The process of making yarn from fibers is called spinning.

Weaving

• The process of arranging two sets of yarns together to make a fabric is calledweaving.

• Weaving of fabric is done on looms.

Knitting

• In knitting, a single yarn is used to make a piece of fabric.• In knitting, a single yarn is used to make a piece of fabric.JUTE

• Jute fiber is obtained from the stem of the jute plant. It is cultivated during therainy season. In India, jute is mainly grown in West Bengal, Bihar and Assam.

• The jute plant is normally harvested when it is at flowering stage.

• The stems of the harvested plants are immersed in water for a few days. The stemrot and fibers are separated by hand.

• To make fabrics, all these fibers are first converted into yarns.www.classmateacademy.com

• Wool and Silk fibers are obtained from animals.

• Wool is obtained from the fleece (HAIR) of sheep or yak.

• Silk fibers come from cocoons of the silk moth.

WOOL :

• Wool comes from sheep, goat, yak and some other animals.

• These wool yielding animals bear hair on their body.

• Hair traps a lot of air. Air is a poor conductor of heat, so, hair keeps these animalswarm.

• Yak wool is common in Tibet and Ladakh

• Angora wool is obtained from angora goats, found in hilly regions such as Jammuand Kashmir

• Wool is also obtained from goat hair, the under fur Kashmiri goat is soft. It is woveninto fine shawls called Pashmina shawls.

• The fur on the body of Camels is also used as wool• Llama and Alpaca, found in South America, also yield wool.


SILK :• Silk fibres are also animal fibres.• Silkworms spin the ‘silk fibres’. The rearing of silkworms for obtaining silk is called

sericulture.

Life history of silk moth• The female silk moth lays eggs, from which hatch larvae which are called caterpillars

or silkworms.• They grow in size and when the caterpillar is ready to enter the next stage of its life

history called pupa. It first weaves a net to hold itself. Then it swings its head fromside to side during these movements of the head, the caterpillar secretes fibre madeof a protein which hardens on exposure to air and becomes silk fibre.of a protein which hardens on exposure to air and becomes silk fibre.

• Soon the caterpillar completely covers itself by silk fibres and turns into pupa.• This covering is known as cocoon.• The further development of the pupa into moth continues inside the cocoon.• The soft silk yarn is as strong as a comparable thread of steel.• Tassar silk, Mooga silk, Kosa silk,Eri Silk are obtained from cocoons spun by different

types of moths.• The most common silk moth is the mulberry silk moth. The silk fibre from the

cocoon of this moth is soft, lustrous and elastic and can be dyed in beautiful colours.


SYNTHETIC FIBRES AND PLASTICS

• Natural fibres like cotton. Wool, silk, etc., are obtained from plants or animals. Thesynthetic fibres. On the other hand, are made by human beings. That is why these arecalled synthetic or man-made fibres.

• Polymer : Poly meaning many and mer meaning part/unit.

Types of Synthetic Fibres

Rayon : Fibre was obtained by chemical treatment of wood pulp. This fibre was calledrayon or artificial silk. Is cheaper than silk and can be woven like silk fibres.

Nylon : It is made without using any natural raw material.It was prepared from coal, water and air. It was the first fully synthetic fibre.We use many articles made from nylon. Such as socks, ropes, tents,toothbrushes, car seat belts, sleeping bags, curtains, etc.

Nylon is also used for making parachutes and ropes for rock climbing.Nylon thread is actually stronger than a steel wire.


Polyester and Acrylic: Polyester is another synthetic fibre. Fabric made from thisfibre does not get wrinkled easily.

• PET is a very familiar form of polyester. It is used for making bottlesutensils, films, wires and many other useful products.

• Fabrics are sold by names like polycot, polywool, terrycot, etc. as thename suggests, these are made by mixing two types of fibres. Polycot isa mixture of polyester and cotton. Polywool is a mixture of polyester andwool.

• We wear sweaters and use shawls or blankets in the winter. Many ofthese are actually not made from natural wool, though they appear toresemble wool. These are prepared from another type of synthetic fibrecalled acrylic.

• All the synthetic fibres are prepared by a number of processes using rawmaterials of petroleum origin called Petrochemicals.


PLASTICS :

• Plastic is also a polymer like the synthetic fibre.

• Plastic which gets deformed easily on heating and can be bent easily are known asThermoplastics. Polythene and PVC are some of the examples of thermoplastics.These are used for manufacturing toys, Combs and various types of containers.

• There are some plastics which when molded once, can not be softened by heating.These are called Thermosetting plastics. Two examples are Bakelite and Melamine.

• Bakelite is a poor conductor of heat and electricity. It is used for making electrical• Bakelite is a poor conductor of heat and electricity. It is used for making electricalswitches, handles of various utensils, etc.

• Melamine is a versatile material. It resists fire and can tolerate heat better than otherplastics. It is used for making floor tiles, kitchenware and fabrics which resist fire.


Polythene Making Polybags

Poly styrene In making Radio and Television sets

Polypropylene In making tube

Teflon Non-sticky cooking ware


PVC In making cable Antenna

Nylon Garment Industry

Tereylene In garment Industry

Plastics as Materials of Choice:

• Plastic is Non-reactivePlastics do not react with water and air. They are not corroded easily.

• Plastic is Light, Strong and DurableTeflon is a special plastic on which oil and water do not stick. It is used for non –

stick coating on cook wares.

• Kevlar : used as bullet proof material


• Fire – proof plastics : Although synthetic fibre catches fire easily, it is interesting to knowthat the uniforms of firemen have coating of melamine plastic to make them flameresistant.

• Plastic and the EnvironmentAs a responsible citizen remember the 4 R principle. Reduce, Reuse, Recycle and

Recover.

How do alcohols affect living beings?

• When large quantities of ethanol are consumed, it tends to slow metabolicprocesses and to depress the central nervous system. This results in lack ofcoordination, mental confusion, drowsiness and lowering of the normalinhibitions.

• The individual may feel relaxed but does not realise that his sense of judgement,sense of timing, and muscular coordination have been seriously impaired.

• Ethanol is an important industrial solvent. To prevent the misuse of ethanolproduced for industrial use, it is made unfit for drinking by adding poisonoussubstances like methanol to it. Dyes are also added to colour the alcohol blue sosubstances like methanol to it. Dyes are also added to colour the alcohol blue sothat it can be identified easily. This is called denatured alcohol.

Alcohol as a fuel• Sugarcane plants are one of the most efficient convertors of sunlight into chemical

energy. Sugarcane juice can be used to prepare molasses which is fermented togive alcohol (ethanol). Some countries now use alcohol as an additive in petrolsince it is a cleaner fuel which gives rise to only carbon dioxide and water onburning in sufficient air (oxygen).


• Unlike ethanol, intake of methanol in very small quantities cancause death. Methanol is oxidized to methanol in the liver.Methanol reacts rapidly with the components of cells. It causes theprotoplasm to get coagulated, in much the same way an egg iscoagulated by cooking. Methanol also affects the optic nerve,causing blindness.

a) Methanolb) Ethanol


causing blindness.

• Temporary hardness is a type of water hardness caused by the presence of dissolved bicarbonate minerals(calcium bicarbonate and magnesium bicarbonate).

• CaCO3 (s) + CO2 (aq) + H2O (l) Ca2+ (aq) + 2HCO3− (aq)

• Permanent hardness caused by sulfate and chloride compounds

• With hard water, soap solutions form a white precipitate (soap

Hardness of Water


• With hard water, soap solutions form a white precipitate (soap scum) instead of producing lather.

2 C17H35COO− (aq) + Ca2+ (aq) → (C17H35COO)2Ca (s)

• Washing soda (sodium carbonate - Na2CO3) is easily obtained and has long been used as a water softener for domestic laundry, in conjunction with the usual soap or detergent.

Detergents : These substances are usually alkylbenzenesulfonates a family of compounds that are similar to soap but are more soluble in hard water.

Soaps : Sodium salts of Higher Fatty Acids like Palmitic Acid.Staric AcidOleic Acid


Micelles

• Soaps are molecules in which the two ends have differing properties, one is hydrophilic,that is, it dissolves in water, while the other end is hydrophobic, that is, it dissolves inhydrocarbons.

• When soap is at the surface of water, the hydrophobic ‘tail’ of soap will not be solublein water and the soap will align along the surface of water with the ionic end in waterand the hydrocarbon ‘tail’ protruding out of water. Inside water, these molecules have aunique orientation that keeps the hydrocarbon portion out of the water. This isachieved by forming clusters of molecules in which the hydrophobic tails are in theinterior of the cluster and the ionic ends are on the surface of the cluster. Thisinterior of the cluster and the ionic ends are on the surface of the cluster. Thisformation is called a micelle.

• Soap in the form of a micelle is able to clean, since the oily dirt will be collected in thecentre of the micelle. The micelles stay in solution as a colloid and will not cometogether to precipitate because of ion-ion repulsion. Thus, the dirt suspended in themicelles is also easily rinsed away. The soap micelles are large enough to scatter light.Hence a soap solution appears cloudy


Oils And Fats :

Esters formed by highly fatty acids and unsaturated acids with glycerol.

Good fat is: Monosaturated fat. An example of a bad fat is: Trans fat.

There are many different kinds of fats, but each is a variation on the same chemical structure. All fats are derivatives of fatty acids and glycerol.


acids and glycerol.

Unsaturated Oils: Olive Oil is liquid at room temperature, thus it’s an unsaturated fat

Saturated Oils: They are solids, Butter is mostly saturated fat

Hydrogenation Reaction


Methane Natural gas

Butane LPG fuel

Acetylene Oxy-Acetylene Flame, Artificial ripening of fruits

Polythene Bottle,Pipes,Buckets

Ethyl Bromide Local Anaesthesia

Chloroform Anaesthesia

Methyl Alcohol Mixing with Petrol and using as fuel,smells like wine but causes blindness and death


wine but causes blindness and death

Ethyl Alcohol Wine, also fuel

Acetone Removal of Nail polish

Formic Acid Preservator of fruits juices

Acetic Acid Vinegar,making sauces

Urea Fertilizer

Oxalic Acid Bleaching of leather,10% solution in cleaning the spots(also part of kidney stones)

Formalin(40% formaldehyde ) Used as preservator

CFC(Freon) Refrigeration

Benzene(discovered by faraday) Father of Aromatic Compounds

Toluene Dry cleaning, Making ofsolvent,TNT(explosive),added to petrol as anti freezer

Nitro Benzene Soaps, Polishes and cheap perfumes,TNB(Explosive)

Aniline Colors,Drugs


Aniline Colors,Drugs

Phenol Bakelite,Aspirin.

Ether Anaesthesia,solvent,coolent

Carbon Tetrachloride Fire Extinguisher

Urotropin Urological Diseases

Gammexene Germicide/Insecticide

Thiokol , Artificial Rubber, Pipes for crude oil, Solvent storage tank,rocket fuel

Neo Prene, Synthetic rubber Insulating material,electriccable,conveyer belt

Sacchrin 550 times sweeter than sugar

Aspartame Sugar free

Acrolene Chloroacetophenone,acrolene

Tear Gas

Mustard gas W.W-1


Mustard gas W.W-1

Methyl Isocyanate(MIC) Toxic gas 1984,Bhopal Gas tragedy

DDT Germicide

RDX(Research and Development Explosive),1899 by Hanning.Cyclo Trimytheline trinitramine

PBE,C-4 derived from this

TNG(Tri Nitro Glycerine) Nobel Oil

TNT(Tri-nitro Toluene) Invented in 1863,W.W.I ,UK used first

Dynamite,Nobel

Drugs


Anasthesia Di-ethyl Ether-First AnasthesiaChloroform,Cocaine,Nitrous Oxide

Anti-Biotics Alexander Fleming-Pencillin(1929)Streptomycin,Gentamycin,Rifamycin

Anti-Septics Iodine,EthylAlcohol,Formaldehyde,HydrogenPeroxide.

Anti-Pyretics Aspirin,Crocin etc

Glass : An amorphous substance which is transparent and made of mainly Silica.

Type of Glass Composition Uses

Fused glass silica Pure silica (100%) Fused quartz is used for high temperature applications such as furnace tubes, lighting tubes, melting crucibles, etc.


Soda-lime-silica glass, window glass

Silica 72% + sodium oxide (Na2O) 14.2% + lime (CaO) 10.0% + magnesia (MgO) 2.5% + alumina (Al2O3) 0.6%

Used for windows, some low temperature incandescent light bulbs.

Photochromatic Glass Silica+ Silver iodide Turns black when exposed to light

Crown’s Glass Soda-lime-silica Eye lenses

Crookes Glass Silica+cerium oxide To absorb ultra-violet energy

Sodium borosilicate glass, Pyrex(Xena Glass)

silica 81% + boric oxide (B2O3) 12% + soda (Na2O) 4.5% + alumina (Al2O3) 2.0%

They are commonly used for reagent bottles, optical components and household cookware.

Lead-oxide glass, crystal glass

silica 59% + lead oxide (PbO) 25% + potassium oxide (K2O) 12% + soda (Na2O) 2.0% + zinc oxide (ZnO) 1.5% + alumina 0.4%

look of glassware more brilliant


Aluminosilicate glass silica 57% + alumina 16% + lime 10% + magnesia 7.0% + barium oxide (BaO) 6.0% + boric oxide (B2O3) 4.0%

glass-reinforced plastics (boats, fishing rods, etc.)

Oxide glass alumina 90% + germanium oxide (GeO2) 10%

Optical fiber

e z > ^ / e - classmate · 2017-03-31 · ' e z > ^ / e Á Á Á x o u u Ç x } u z u ]...

Documents