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Tuesday, 7 April 2020

Facts about Solutions and Water

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Facts about Solutions

A solution is a homogeneous mixture of two or more substances, whose composition can be varied within certain limits.

The substances forming a solution are called components.

Solute and solvent are the components of a solution.

A solvent is the dissolving substance and a solute is the dissolved substance

eg: When salt is dissolved in water the salt is the solute and water is the solvent.

The component present in larger quantity is called the solvent and the other one, the solute.

Solubility is the maximum amount of solute that can be dissolved in the fixed amount of solvent.

A solution containing maximum amount of solute at a given temperature and pressure is called saturated solution.

A solution containing less than maximum quantity of solute in a solvent is called unsaturated solution.

Normality is the number of gram equivalents of solute present in one litre of the solution.

Molality is the number of moles of the solute that are present in 1 kg of the solvent.

Molarity is the number of moles of solute present in litre of the solution.

The process of crystals depositing from a solution is called crystallization.

The finer the particles, the more are the solubility.

The more the shaking or agitation, the more is the solubility.

The higher the temperature, the greater is its solubility.

Milk, blood, creams are emulsion type colloidal solutions.

Isotonic solutions are solutions which have same osmotic pressure.

Solution (Homogeneous mixture of two or more substance) – Solute and Solvent.

Solute -> Dissolved substance -> Smaller component -> In salt solution, solute is salt
Solvent -> Dissolving substance -> Larger component -> Water is solvent in salt solution

Facts about Water

Water is known as the ‘Universal Solvent’ because it is a remarkable solvent and dissolves many susbtances forming aqueous solutions.

Water exists in all three states of matter.

Water has the greatest density at 4°C. This behaviour of water permits fishes to survive in ponds through severe winters.

Oxide of deuterium is called heavy water.

Water is a poor conductor of heat and electricity.

The pleasant taste of good drinking water is due to dissolved air and CO2 and mineral water.

Water acts both as an acid and a base.

Hard water does not produce lather with soap readily.

Soft water produces lather with soap readily.

Temporary hardness of water is due to the presence of bicarbonates of calcium and magnesium. It can be removed by boiling the water.

Permanent hardness of water is due to the presence of sulphates and chlorides of calcium and magnesium. It can be removed by adding washing soda or by ion exchange method.

Water (H2O) Properties

1. Universal Solvent
2. Exist in three states (Ice, water, steam)
3. Heavy water -Deuterium oxide
4. Maximum density at 4°C
5. Water is divided into Soft water and Hard water
6. Soft water -> Produce lather with soap readily
7. Hard water -> Does not produce lather with soap readily -> Temporary hardness & Permanent hardness
8. Temporary hardness -> Presence of bicarbonates of calcium and magnesium
9. Permanent hardness -> Sulphates and chlorides of calcium and magnesium

Monday, 6 April 2020

Facts about Acids, Bases and Salts

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FACTS ABOUT ACIDS, BASES & SALTS


FACTS ABOUT ACIDS

Acids are substances which produces hydronium ion (H3O+) in its aqueous solution.

An acid is sour in taste.

An acid turns blue litmus paper into red.

Sulphuric acid is also known as 'Oil of Vitriol'.

'King of chemicals' is sulphuric acid.

It is manufactured through 'contact process'.

Pure, concentrated sulphuric acid is a bad conductor of electricity while the dilute acid is a good conductor of electricity.

Sulphuric acid is used in the manufacture of chemicals, dyes and pigments, soaps and detergents, plastics and fibres (rayon).

It is used in the manufacture of fertilizers (super phosphate of lime, ammonium sulphate), explosives (nitroglycerine and trinitro toluene (i.e., TNT). a It is used in petroleum refining, tempering of steel and in lead storage batteries.

Earliest known acid is acetic acid.

Substance and Acid

1. Oranges, Lemon - Citric acid
2. Tamarind, Grapes - Tartaric acid
3. Tea - Tannic acid
4. Vinegar - Acetic acid
5. Urine - Uric acid
6. Ant - Formic acid
7. Milk, Curd - Lactic acid
8. Fat - Stearic acid
9. Olive oil - Oleic acid
10. Apple - Maleic acid, Ascorbic acid

The acid that can be used as a hypnotic is barbituric acid.

Old name of hydrochloric acid is muriatic acid.

The acid that functions as digesting agent in our body is hydrochloric acid.

Dilute phenol is called carbolic acid.

Weakest (inorganic) acid is hydrocyanic acid.

The acid which fumigates when exposed to air is nitric acid.

To purify gold, it should be treated with concentrated nitric acid.

Old name of nitric acid is aquafortis.

Acid and Use

1. Citric acid - Food preservation, Vitamin C preparation
2. Oxalic acid - Ink stain remover
3. Boric acid - Eye-wash/antiseptic
4. Carbonic acid - Flavoured drinks
5. Tartaric acid - Baking powder
6. Acetic acid - Flavouring food, food preservation
7. Hydrochloric acid - Cleaning of metal items, printing industry
8. Benzoic acid - Preservation of fruit pulps and making of perfumes and medicines
9. Nitric acid - Explosives
10. Phosphoric acid - Fertilizers

Gastric juice contains hydrochloric acid Cola contains phosphoric acid.

Ordinary soda water is chemically carbonic acid.

Tartaric acid: Constituent of baking powder (reacts with sodium bicarbonate to release car-bon dioxide which makes the dough light and spongy).

FACTS ABOUT BASES

Oxides and hydroxides of metals (or metal like radicals) are called bases.

Sodium hydroxide: Manufacture of soap.

Calcium hydroxide:

i) Manufacture of bleaching powder, mortar
ii) Softening of hard water,
iii) Neutralizing acid in the soil and in water supplies.

Potassium hydroxide: Alkaline batteries.

Magnesium hydroxide: As an antacid to neutralize acidity caused by hydrochloric acid in the stomach.

Aluminium hydroxide: Foaming agent in fire extinguishers.

Ammonium hydroxide: Used to remove grease stains from clothes.

pH value

The measure of the acidic or basic character of a liquid or solution is the pH value.

The pH scale is introduced by Sorensen.

pH value generally starts from 0 and ends at 14

Pure neutral solutions are having pH exactly 7.

pH value greater than 7 and upto 14 is basic.

pH value 0 to 6.9 is acidic.

Generally human secretions other than blood have pH 6.1 to 6.9.

The solutions which resist change in pH on dilution or with the addition of small amounts of acid or alkali are called Buffer Solutions.

pH Value

1. Pure water - 7
2. Sea water - 8.5
3. Human blood - 7.3 or 7.4
4. Saliva - 6.5 - 7.4
5. Coffee - 5
6. Tea - 5.5
7. Milk - 6.5
8. Bear - 4.5
9. Acid rain - 3.00 - 4.5
10. Lemon juice - 2.4

FACTS ABOUT SALTS

Salts are ionic compounds containing a positive ion (cation) and a negative ion (anion).

Sodium chloride (NaCI) is a normal salt.

Hydrolysis is a reaction in which a salt reacts with water to form a solution which is either acidic or alkaline.

Salts containing water of crystallisation are called hydrated salts.

Sodium chloride is used as a flavouring agent in food.

Sodium bicarbonate is an essential ingredient in baking powder.

Sodium carbonate as washing soda, manufacturing of glass etc

Sodium benzoate as a food preservative for pickles

Potassium nitrate is used in the production of gun powder.

What is Hygroscopy?

Ans: Hygroscopy is the property of salts to absorb atmospheric moisture at ordinary temperature without dissolving in it. Anhydrous calcium chloride, conc. sulphuric acid, phosphorus pentoxide, calcium oxide (quick lime), silica gel, alcohol are the examples of hygroscopic substances.

Calcium chloride: Dehydrating agent used for removing moisture from gases.

Calcium carbonate (Lime stone): In the construction of building, cement industry.

Characteristics of Acids and Bases

Acid -> Sour taste -> Blue litmus to red -> Give H+ ions in solution
Base -> Bitter taste -> Red litmus to blue -> Give OH- ions in solutions

Saturday, 4 April 2020

Facts about Compounds in Chemistry

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Facts about Compounds
Compound is a pure substance that is composed of two or more elements chemically combined in definite and constant proportions.

The separation of a compound into its elements by chemical means is called analysis.

The formation of a compound by the union of elements is called synthesis.

The common refrigerants are Ammonia and Freon- 12

Non stick kitchen vessels are coated with Teflon.

Photographic films are coated with Silver bromide.

Artificial rain is done by using Silver iodide.

Phosphene (PH3) has the smell of rotten fish.

Hydrogen sulphide gas has the smell of rotten egg.

Bleaching powder is chemically calcium hypochlorite (Ca(ClO)2).

Egg shell, marble, limestone etc contain Calcium carbonate.

Coral reefs are made of calcium carbonate.

Green house effect is created by carbondioxide, methane, water vapour etc.

Dry ice is solid carbondioxide.

Zinc phosphide and Arsenic sulphide are used as rat poison (rodenticide)

What is Acid rain ?

Ans: The term Acid rain was coined by Robert Angus Smith. It is caused by the pollution of environment due to nitrogen oxide and sulphur dioxide. Sulphur dioxide and nitrogen oxides are changed in the atmosphere into sulpuric acid and nitric acid.

Laughing gas is Nitrous oxide.

Benzyl chloride is used as tear gas.

Carborundum is Silicon Carbide.

Potassium Cyanide is used to reduce the melting point of gold.

Sodium Citrate is used as a preservative for human blood.

Water glass is sodium silicate.

Sodium peroxide is used as air purifier in submarines.

Paper is chemically cellulose.

The most abundant carbohydrate (organic com-pound) present in nature is cellulose.

Rust is chemically hydrated ferric oxide. (Fe2O3.H2O).

Freezing mixture contains calcium chloride.

The gas responsible for Bhopal gas tragedy was methyl iso cyanate (MIC).

Copper oxy chloride is used as fungicide in pepper plants.

Oxides are binary compounds of oxygen and metals or non metals.

Acidic oxides show the properties of acids.
eg: Carbon dioxide, sulphur dioxide, phosphorus pentoxide etc.

Basic oxides are generally metallic oxides. 
eg: Calcium oxide, sodium peroxide, magnesium oxide, etc.

Neutral oxides are neither acidic nor basic. 
eg: 1. Nitrous oxide 2. Carbon monoxide (CO)

Amphoteric oxides show both the properties of acids and bases.
eg: Aluminium oxide, zinc oxide, water

Ordinary Portland Cement (OPC) contains the major component calcium oxide (Lime)

White paints are made by using titanium dioxide.

The whitest compound ever known is titanium dioxide.

Most abundant compound present in animals -Water.

Nitrous oxide is used as an anesthetic.

Rocket propellant contains fuel and oxidiser.

Impure sodium carbonate obtained in the industrial process is called black ash.

Lead chromate is used as pigments called chrome yellow.

Ferromagnetic powder is coated in tape recorders.

Carbon dioxide is used in fire extinguishers.

Cryolite is a double fluoride of aluminium and sodium.

Silver halides are used in photographic plates because they are readily reduced by light.

The aluminium compound used in fire extinguishers is alum.

Calcium compound used in freezing mixture is calcium chloride.

The chemical used as a 'fixer' in photography is sodium thiosulphate. It is also known as hypo.

Diffusion of light in the atmosphere takes place due to water vapour.

Ferrous sulphate crystals are known as 'Green vitriol'.

The main constituents of pearl are calcium carbonate and magnesium carbonate.

Ruby, sapphire, emery or corundum is aluminium oxide ( Al203).

Smelling salt is ammonium carbonate (NH4)2CO3.

Philosopher's wool is zinc oxide.

Nitrous oxide gas, N2O is used in the manufacture of ice - cream.

Naturally occurring aluminium silicate is mica. Mica is a bad conductor of electricity and a good conductor of heat.

Ice has lower density than water. Why?

Due to hydrogen bonding in the solid state an open cage like structure is formed as a result of which mass per unit volume decreases and hence the density.

Rock cotton is asbestos.

Methyl bromide is used as pesticide.

HBFCs ie. hydrobromofluorocarbons used in fire entinguishers.

Sodium nitrate is used as fertilizer, it is also known as Chile salt petre.

Potassium ferrocyanide is used in the manufacture of prussian blue.

Most ionic compound is Cesium chloride.

Calcium phosphate is found in the bones of animals.

Vegetable gold is Saffron.

Baking powder is a mixture of tartaric acid and baking soda.

A mixture of Titanium tetrachloride and Tri-ethyl aluminium is known as Zeigler - Natta catalyst.

Mixture of Copper sulphate and calcium hydroxide is known as bordeaux mixture. it is used as a fungicide.

Gun powder is a mixture of sulphur, charcoal and nitre.

Ammonia

Ammonia is a compound of nitrogen and hydrogen with the formula NH3.

It is an intermediate gaseous product in the decaying process of dead organic matter.

Industrially, it is manufactured through Haber's Process.

It is a colourless gas with a strong pungent smell and slightly alkaline taste.

It is lighter than air.

Highly soluble in water

It is used in the manufacture of fertilizers, nitric acid and sodium carbonate.

Nylon, rayon, plastics, dyes, and explosives are all made from ammonia.

Ammonia can be liquefied easily and liquid ammonia is highly volatile.

Ammonia emulsifies fats and grease so that they can be removed without leaving any residue. Thus, it acts as a cleaning agent.

Compounds and its uses

1. Silver Iodide –> For artificial rain
2. Formaldehyde –> Preservation of dead body
3. Sodium Citrate –> An anti coagulant in Blood bank
4. Sodium Benzoate –> For the preservation of grains and food
5. Silver Bromide –> For the manufacturing of photo films
6. Freon –> Use in refrigerator as a coolant
7. Sodium Peroxide –> Air purifier in sub marines
8. Carbon dioxide –> Fire extinguisher

Friday, 3 April 2020

Facts about Metals, Nonmetals and Metalloids

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Facts about Metals, Non Metals and Metalloids


The elements which lose electrons in chemical reaction are called metals.

A metal is an electropositive element which is hard, lustrous, malleable, ductile with tensile strength, and a good conductor of heat and electricity.

Metals form basic or amphoteric oxides.

Metals can be hammered into very thin sheets. This property is called malleability.

Cold and silver are among the best malleable metals.

The property of metals capable of being drawn into wires is known as ductility.

Gold is the most ductile of all the metals.

Metals can be stretched to some degree without fracturing. This is a measure of their tensile strength.

Some metals like tungsten have very high tensile strength.

Metals and Ores

1. Potassium - Sylvine
2. Sodium - Rock salt
3. Calcium - Lime stone, Gypsum. Dolomite
4. Magnesium - Magnesite
5. Aluminium - Bauxite, Cryolite
6. Chromium - Chromite
7. Manganese - Pyrolusite, Rhodochrosite
8. Zinc - blende, Calamine
9. Copper - Chalcocite, Malachite, Cuprite, Azurite
10. Mercury - Cinnabar
11. Silver - Argentite, Horn silver
12. Titanium - Rutile, Ilmanite
13. Thorium - Monozite
14. Uranium - Pitch blende
15. Iron - Haematite, Magnetite
16. Lead - Galena, Litharge

Metallurgy is the process of extracting metal, in a pure state on a large scale from its ore by physical and chemical means.

Minerals are the naturally occurring chemical substances in the earth's crust, which are obtained by mining.

Ore is the mineral from which the metal is conveniently and economically extracted

Ore has definite composition (formula)

Gangue is the impurity present in the ore. Generally gangue is silica.

A substance added to ore to remove impurities is called flux.

There are two types of flux: Acidic flux and Basic flux.

Acidic flux is added to remove basic impurity.

Basic flux is added to remove acidic impurity.

Acidic flux is silica.

Basic flux is quick lime.

In the extraction of iron, calcium carbonate acts as a flux.

Combination of gangue with flux in ores forms a fusible material called Slag.
Gangue + flux --> Slag

Sulphide ores are purified by Froth-floatation process.

Tinstone, Pyrolusite etc are purified by magnetic separation.

Calcination is the process of heating the ore below its melting point in absence of air to remove volatile impurities like, arsenic.

Roasting is heating the ore below its melting point in air to oxidise the impurities.

Liquation is used to refine metals having a low melting point.
eg: Lead and tin.

The method used for refining metals containing volatile impurities is oxidation.

Distillation is used to refine volatile metals like mercury and zinc which contain non-volatile impurities.

Electro - refining is an economical and effective method for purifying metals.
eg: Cu, Al

Hardest metal - chromium

Vermilion, a scarlet pigment used in art deco-ration is made from the mercury ore, Cinnabar (Mercury sulphide).

Gold and platinum occur exclusively in free state.

Most of the metals occur in the form of oxides, sulphides, carbonates, sulphates, chlorides and silicates.

Metals extracted from sea-water are magnesium and sodium. Metals generally accumulated in living organisms - Vanedium, Potassium.

Most abundant metal present in developed animals - Calcium.

Major metals present in chloroplast are magnesium, manganese, copper and iron.

The second most abundant metal in earth crust is Iron.

The metal related to arthritis is potassium.

The metal present in Insulin is zinc.

Zinc is concentrated on the eyes of human beings.

The lightest metal - Lithium

Liquid metal at room temperature is mercury.

Liquid non-metal at room temperature is bromine.

The non-metal, which shows electric conductivity - Graphite (Carbon)

The most harmful metal to human beings is Lead.

Metals kept under kerosene are sodium, potassium, caesium etc.

Tin is the only metal which has maximum number of stable isotopes (10).

Some elements behave chemically both as met-als and non-metals. Such elements are called metalloids.
eg: Boron, Silicon. Germanium etc.

The first known super conductor is mercury.

Lithosphere is the solid phase of the earth and is made of different types of rocks.

Lithosphere is the major source of metals.

The first metal to be used by man is copper.

Core is the central portion of earth.

Metallic core contains valuable metals like manganese, iron, cobalt, nickel, copper, iridium, platinum, gold etc.

Most abundant metal present in blood is potassium.

A non-metal is an electronegative element which occurs as solids, liquids and gases. They are generally poor conductors of heat and electricity.

Non-metallic solids are usually soft and brittle.

Non-metals form acidic or neutral oxides.

Silver is the best conductor of heat and electricity.

The metal, silver is an excellent reflector.

Metals like gold and copper are mostly found in old igneous rocks.

Cobalt is useful in making rust resistant alloys.

Silver, platinum and gold are known as noble metals.

Iron rarely occurs in free state because it is very reactive.

Mercury flows so easily and rapidly that it is sometimes called quick silver.

Metal present in the bath soap is potassium.

Metals usually combine with oxygen to form basic oxides.

Some metals react with water. Sodium reacts violently even with cold water forming sodium hydroxide and hydrogen. Gold does not react even with steam.

Some metals react with acid and replace the hydrogen atom in their molecules. Gold, copper and silver are unaffected with hydrochloric acid.

Mercury is the metal having lowest melting point (-39°C).

When iron rusts, its weight increases.

Titanium is the metal of future.

Sparkling and colour after the blast of fire crack-er is due to the presence of strontium.

Properties of Metals

(1) Lustrous (means shining appearance)
(2) Electropositive
(3) Malleable -> Hammered into thin sheets -> Gold and silver
(4) Ductile -> Drawn into thin wires -> Gold
(5) Tensile strength -> Stretched without fracturing -> Tungsten
(6) Good conductor of heat and electricity

Enamels are mixtures of silicates, backed on to iron or steel object.

Iron coated with zinc is called galvanised iron and with tin is called tin plate.

Compounds of fluorine are used as cooling agents in refrigerators.

Fluorinated polymer, teflon, finds numerous uses as it is tough and fire resistant.

Rhombic sulphur is the most stable form of sulphur and exists at room temperature.

Phosphorus is used in the fertiliser industry.

Alloys

An alloy is a homogeneous mixture of a metal with other metals and non-metals.

Alloys are generally made by mixing the metals in a molten state.

Electrium is an alloy of gold and silver.

Amalgam is an alloy in which one of the components is mercury.

Alloys are generally harder and more resistant to corrosion.

The properties of an alloy are different from those of the constituent metals.

Alloys are also called solid solutions.

IMPORTANT ALLOYS, CONSTITUENTS AND USES

Alloys
Constituents
Uses
1. Steel
Iron (Fe), Carbon (C)
Construction of ships, tanks, railway lines, bridges and machinery.
2. Aluminium Bronze
Aluminium (Al), Copper (Cu) 
to make coins, statues, ornaments
3. Invar
Iron (Fe), Nickel (Ni), Carbon (C)
To make clock pendulum, scientific measuring instruments.
4. Bronze (Bell Metal)
Copper (Cu), Tin (Sn)
Statues, Ornaments, coins, cooking utensils, bells and medals.
5. Alnico
Aluminium (Al), Nickel (Ni), Cobalt (Co), Iron (Fe)
To make magnets
6. Nichrome
Nickel (Ni), Chromium (Cr), Iron (Fe), Manganese (Mn)
To make heating elements
7. Manganese
Steel Iron (Fe), Carbon (C), Manganese (Mn)
To make rock driller, plates, rails, protecting shields etc
8. Constantan
Copper (Cu), Nickel (Ni)
To make electrical instruments
9. Brass
Copper (Cu), Zinc (Zn)
Utensils, parts of machinery, wires, musical instruments, ornamental
objects
10. Duralumin
Aluminium (Al), Copper (Cu), Magnesium (Mg), Manganese (Mn)
Aircraft parts, light tools

11. Magnalium
Aluminium (Al), Magnesium (Mg)
External parts of troller, steamer etc
12. Phospher Bronze
Copper (Cu), Tin (Sn), Phosphorus (P)
Springs and suspension filament in electrical instruments
13. Silumin
Aluminium (Al), Silicon (Si)
Engine parts
14. Type Metal
Copper (Cu), Lead (Pb), Tin (Sn), Antimony (Sb)
To make types in printing
15. Chrome Vanadium Steel
Iron (Fe), Carbon (C), Chromium (Cr), Vanadium (V)
Axils of motor cars
16. Sterling Silver
Copper (Cu), Silver (Ag)
Silver coins
17. Coinage Silver
Copper (Cu), Nickel (Ni)
Coins
18. Chrome Steel
Iron (Fe), Carbon (C), Chromium (Cr)
Springs, tools etc
19. Gun Metal
Copper (Cu), Zinc (Zn), Tin (Sn)
Barrels of gun
20. Nickel Steel
Iron (Fe), Nickel (Ni), Carbon (C)
Electric wire cables, automobile parts
21. German Silver
Copper (Cu), Nickel (Ni), Zinc (Zn)
Utensils, resistance wire etc
22. Stainless Steel
Iron (Fe), Chromium (Cr), Nickel (Ni), Carbon (C)
Cooking utensils, cutlery, surgical instruments
23. Solder
Lead (Ph), Tin (Sn)
Electrical connections, fuse wire