CTEVT Chemistry Note : Inorganic Chemistry(IV) : Metals and Minerals.

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CHAPTER-8 : METALS

Metals are those natural elements which are generally solid, hard, lustrous and higher in density. Metals have a very high boiling and melting point. They effectively conduct heat and electricity. In metals, the atoms are arranged in the crystal structure.

Metals generally contain 1,2, or 3 electrons in their outermost shell. Some examples of metals are silver, aluminium, gold, lead, nickel, copper, magnesium, iron, cobalt, zinc, etc.

Differences between metals and non-metals :
     Metals            Non- metals
1.They are generally good conductor of heat and electricity.

2. They are malleable {i.e. they can be hammered into thin sheet} and ductile {i.e. they can be drawn in the form of wires}

3.Metals generally have high melting and boiling points and density

4. The number of electrons in the outer shell is generally 1-3.

5.They react with dilute acid to liberate hydrogen gas

6. Metallic oxides are generally basic in nature. Eg. Na2O, MgO, CaO,etc

7. They are electropositive in nature and form cation by loss of electron.

 1.They are bad conductor of heat and electricity except graphite.

2. They are not malleable and ductile.

3. Non metals generally have low melting and boiling points and density.

4.The number of electrons in the outer shell is generally 4-8.

5.They do not liberate hydrogen gas with acids.

6. Non-metallic oxides are generally acidic in nature. Eg. CO2, SO2,NO2, etc.

7. They are electronegative in nature and form anion by gain of electron.
Differences between minerals and ores
      Minerals         Ores
1. Mineralsare the naturally occurring substance which contains some amount of metals. They are found in the earth crust and obtained by mining.

2. All minerals are not ores.

3. Eg. bauxite (Al2​O3​⋅2H2​O) and clay (Al2​O2​⋅2SiO2​⋅2H2​O) are minerals of Al.

 1.Ores are the specific minerals from  which metals can be economically and conveniently extracted.

2.All ores are essentially minerals too.

3.Eg. bauxite is an ore of Al as Al can be economically and conveniently extracted from bauxite.
Differences between flux and slag :
Flux Slag
  1. It is a compound which is used in metallurgical process to remove (extract) gangue(unnecessary elements in ore) material during the extraction of element from ore.
  2. Properties of Flux: It must only react with gangue not with our element that we are extracting.
  1. Slag is the waste material which is removed (i.e. Flux react with gangue to leave slag)
  2. Property of slag: Slag is lighter than our molten metal and it form thick layer on the surface of molten metal to cut off contact of air with our metal and stop its oxidation reaction.
Differences between calcinations and roasting :
Calcination Roasting
  1. Calcination is a process of heating the concentrated ore at a temperature below its melting point in absence or limited supply of air to convert the ore into dry metallic oxide.
  2. This process is used in oxygen containing eg. oxide, hydroxide or carbonate ore.
  3. Example:
  1. Roasting is a process of heating the concentrated ore at a temperature below its melting point in presence of excess of air to convert the ore into dry metallic oxide.
  2. This process is used in non-oxide (eg. Sulphide) form of the ore.
  3. Example:

Chemistry ( Preparation, properties and uses) of some compounds :

 1. Plaster of Paris (CaSO4. 1/2H2O) :

Plaster of Paris is calcium sulphate hemihydrate and is represented by CaSO4. 1/2H2O or 2CaSO4. H2O.

Preparation: It is prepared by heating gypsum (rock) at about 140oC.

Properties :

  1. It is white and amorphous powder.
  2. It is insoluble in water.
  3. When powdered plaster of Paris is mixed with little water, it is converted into its paste which sets into hard solid mass within 5 to 15 minutes. This process is called setting of plaster.

Uses :

  1. It is used in surgery for plastering (i.e. setting) the fractured bones.
  2. It is used for making molds (casts) for statues and other decorative materials.
  3. Used for making black board chalk.
  4. Used for making artificial marble.
 2. Bleaching powder (CaOCl2) :

Its chemical name is calcium oxychloride or calcium chloro hypochlorite Ca(ClO)Cl.

Preparation : It is prepared by the action of chlorine gas on dry slaked lime.

Properties :

1. It is pale yellow amorphous powder.

2. Solubility : It is soluble in water. It gives Ca(OH)2 and Cl2 with water.

3. Action of air : When bleaching powder is exposed to air, it reacts with atmospheric carbon dioxide liberating Cl2 hence odour of chlorine is produced from bleaching powder.

4. Catalytic decomposition : When bleaching powder is heated with cobalt chloride as catalyst, Oxygen gas is evolved.

5. Bleaching action : When bleaching powder is mixed with small quantity of dilute mineral acid, hypochlorous acid is formed, which decomposes giving nascent oxygen. This nascent oxygen is responsible for converting coloured substance into colourless substance.

Uses :

  1. It is used as bleaching agent.
  2. It is used in the manufacture of chloroform (CHCl3).
  3. It is used as germicide and disinfectant in the purification of drinking water.

 3. Epsom salt ( MgSO4. 7H2O) :

Epsom salt is chemically magnesium sulphate heptahydrate( MgSO4. 7H2O).

Preparation :

1. Commercially, it is prepared by the action of dilute sulphuric acid on magnesium carbonate ( magnesite ore).

The resulting aqueous solution is subjected to crystallization to get crystals of Epsom salt.

2. It is also prepared by the action of dilute sulphuric acid on dolomite.

The insoluble CaSO4 is removed by filtration and filtrate is crystallized to obtain crystals of Epsom salt.

3. Magnesium sulphate is prepared by dissolving magnesium metal or magnesium oxide with dil. H2SO4.

The solution is concentrated and on cooling crystals of magnesium sulphate, MgSO4. 7H2O are formed.

Properties :

1. It is colourless crystalline solid.

2. It is efflorescent in nature.( loses water of crystallization slowly)

3. Action of water : It is highly soluble in water. The aqueous solution of magnesium sulphate is acidic in nature due to formation of strong acid and weak base.

4. Action of alkali : It gives white precipitate of magnesium hydroxide with caustic alkali solution.

5. Action of heat : when it is heated to about 2000C, anhydrous form is obtained. On further heating, it decomposes to give MgO and SO3 gas.

Uses :

  1. It is used as a purgative (laxative) in medicine.
  2. It is used to correct magnesium and sulphur deficiency of soil.
  3. It is used to prepare fire proof fabrics.
  4. It is used in the manufacture of paint, soap, etc.
 4. Silver nitrate:

Preparation : silver nitrate is prepared by dissolving silver metal in warm dil. nitric acid. The resulting solution is crystallized to obtain silver nitrate crystal.

Properties :

1. It is colourless and crystalline solid.

2. It is soluble in water.

3. When it is strongly heated, it decomposes to form metallic silver.

   

4. Action with halides: AgNO3 solution reacts with halides to give ppt. of silver halides.

5. Action with ammonia : Silver nitrate reacts with ammonia to form a complex i.e. diamine silver nitrate.

6. Action with sulphide salt: Silver nitrate solution reacts with metal sulphide to form black ppt. of silver sulphide.

Uses :

  1. It is used as laboratory reagent to detect halides.
  2. It is used to prepare Tollen’s reagent.
  3. It is used to prepare silver halide salts used in photography.
  4. It is used in preparation of indelible (permanent) ink.
 5 . Calomel(Hg2Cl2) :

Calomel is mercurous chloride , Hg2Cl2.

Preparation :

1. It can be prepared by heating mercury with mercuric chloride.

2. It can be prepared by treating mercurous nitrate solution with chloride salts.

3. It can be prepared by the action of mercuric chloride with stannous chloride.

Properties :

1. It is white amorphous solid.

2. It is insoluble in water. However, it dissolves in chlorine water forming mercuric chloride.

3. It decomposes on heating to give metallic mercury and mercuric chloride.

4. Calomel is reduced by stannous chloride to give metallic mercury.

5. It reacts with alkali like NaOH to give black ppt. of Hg2O.

Uses :

  1. It is used as purgative in medicine.
  2. It s used to make calomel electrode (which is used as standard reference electrode).
  3. It is used as fungicide.
 6. Corrosive sublimate ( HgCl2) :

Corrosive sublimate is mercuric chloride, HgCl2.

Preparation :

1. It is prepared by heating mercury with excess of chlorine.

2. It is prepared by heating mercuric sulphate with sodium chloride.

3. It can also be prepared by treating mercuric oxide with dilute hydrochloric acid.

Properties :

1. It is white crystalline solid.

2. It is soluble in water and organic solvents such as alcohol, ether, etc.

3. It is highly poisonous and causes death.

4. When it is heated with mercury, it gives mercurous chloride.

5. Mercuric chloride reacts with stannous chloride and formes mercurous chloride.

6. HgCl2 solution reacts with NaOH to give yellow ppt. of mercuric oxide.

Uses :

  1. It is used as a fungicide in agriculture.
  2. As antiseptic to sterilize surgical instruments.
  3. As a preservative of wood(timber)
 7. Red oxide of copper ( Cu2O) :

Cuprous oxide or copper(I) oxide is commonly called red oxide of copper.

Preparation :

1. It is prepared by the reduction of cupric oxide using reducing agent like glucose solution.

2. It is prepared by heating copper in air above 11000C.

Properties :

1. It is reddish amorphous powder.

2. It is insoluble in water.

3. When red oxide is heated strongly in air, it turns to black oxide of copper(cupric oxide).

4. It reacts with hydrogen on heating to form metallic copper.

5. It is a basic oxide and reacts with conc. HCl to give cuprous chloride salt.

Uses :

  1. It is used in glass industry to prepare red coloured glass.
  2. It is used as an antirust paint.

CHAPTER- 9 : Minerals

Minerals are substances that are formed naturally in the Earth. Minerals are usually solid, inorganic, have a crystal structure, and form naturally by geological processes.

Minerals in food : Minerals are inorganic nutrients found in foods that are essential for growth and health and do not contain the element carbon.

Mineral Function (biological importance) Sources Deficiency
Sodium

(Na)

 ♦ Needed for proper fluid balance (regulate osmotic pressure of body fluids),

♦ for generation of nerve impulses and muscle contraction.

 ♦ Table salt(sodium chloride);

♦ Large amounts in processed foods,

♦ Small amounts in milk, breads, vegetables, and unprocessed meats.

 ♦ The Improper functioning of nerves and muscles,

♦ Nausea, cramps, vomiting, dizziness, possible respiratory failure.
Potassium

(K)

 ♦ Needed for proper fluid balance (regulate osmotic pressure of body fluids),

♦ Influences muscle activity, especially cardiac muscle.

 ♦ Meats, milk,

♦ Fruits especially banana, orange juice and dried fruits,

♦ Vegetables

 ♦ Muscle weakness

♦ Cardiac diseases

♦ Respiratory failure
Calcium

(Ca)

 ♦ Important for healthy bones and teeth;

♦ Helps muscles relax and contract;

♦ Important in nerve functioning, blood clotting, blood pressure regulation, immune system health.

 ♦ Milk and milk products;

♦ Fish with bones,

♦ Green vegetables(broccoli, mustard greens); legumes,

♦ “hard” drinking water.

 ♦ Ricket- abnormal development of bones,

♦ osteoporosis : when you’re older, your bones break very easily due to the slow loss of bone mass

♦ short-term deficiency may cause muscle cramps, stiffness(inflexibility) and poor mobility.
Magnesium

(Mg)

 ♦ Needed for making proteins.

♦ Found in bones;

♦ Muscle contraction, nerve impulse transmissions, immune system health.

 ♦ Milk, Nuts and seeds (legumes);

♦ Leafy, green vegetables;

♦ Sea food; chocolates.

♦ “hard” drinking water

 ♦ Muscle tremors (shaking), seizure.

♦ Irritability (state of being irritate).
Iron

(Fe)

 ♦ Essential for the formation of haemoglobin found in red blood cells that carries oxygen in the body;

♦ Increases resistance to infection

♦ Functions as part of enzymes involved in tissue respiration

♦ Needed for energy metabolism.

 ♦ Organ meats; red meats; fish; poultry; shellfish (especially clams); Egg yolks;

♦ legumes; Dried fruits;

♦ Dark, leafy greens; iron-enriched breads and cereals.

 ♦ Iron deficiency cause anemia: it happens due to decrease in number of haemoglobin in red blood cells. Symptoms can include headache, chest pain, and pale skin.

♦ Irritability, lethargy.
Zinc

(Zn)

 ♦ Part(component) of many enzymes; needed for making protein and genetic material;

♦ has a function in taste perception, wound healing,

♦.normal fetal development, production of sperm, normal growth and sexual maturation, immune system health.

 ♦ Meats, fish, poultry,

♦ leavened whole grains, vegetables.

 ♦ Decreased wound healing,

♦ decreased taste acuity,

♦ hair loss, diarrhea,

♦ growth failure

(retardation)

⇐  See previous chapters.. . 

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