Carbon & It's Compounds

• Diamonds are the hardest known natural material.
• Graphite is used as an electrical conductor, lubricant, and waterproofing agent.
• Diamond is chemically very inert due to it's compact structure (does not react with most chemicals)
• Graphite is slightly more reactive than diamond due it's more open area than diamond (more prone to chemical attacks)
• Carbon occurs in free state and in combined state
• In free state-

  carbon occurs in crystalline forms that is crystals like diamond and graphite & in the amorphous form that is impure as coal found under the earth's surface.
• In combine state-

  • Carbon occurs as carbon dioxide in atmosphere
  • It is found in wood as cellulose
  • In plants & animals as carbohydrates
  • In minerals as limestone (CaCO3)
• Allotropy-

  Allotropy is the existence of an element in more than one one physical form having different different physical properties, but the same graded chemical properties
• Coal - uses

  • For manufacture of coal, coal gas, petroleum
  • Mainly used as a cheap fuel also a fossil fuel)
• Coke - uses

  • As a fuel burns without smoke)
  • As a reducing agent in iron & steel industry
• Lampblack or soot - uses

  • As a black shoe polish, black paint, typewriter ribbon
  • As a filler in rubber tyre
• Wood Charcoal - uses

  • As a decolourising agent it adsorbs organic coloring matter.
  • As an household fuel it burns without smoke and is easy to ignite.
• Types of Coal - Anthracite, Bituminous, Lignite, Peat

  • Peat 60%
  • Lignite 65%
  • Bituminous 85%
  • Anthracite 90%
• Transformation of vegetable matter -

  By slow bacterial decomposition of matter. It is influenced under the heat, pressure & limited air, over millions of years.

  The different stages of transformation of matter results in a residue varying amounts of carbon giving different types of coals.
• Wood Charcoal used for reducing heated metallic oxides to their respective metals.
• $ZnO +$$C - Zn +$$CO$
• Coke is made from coal by heating at high temperature (1200°C) in absence of oxygen. The volatile substances are driven off leaving behind pure carbon.
• In free state carbon dioxide occurs as:

  • Respiration by living organisms
  • Decay & decomposition of organic matter e.g. Plants & animals.
  • Burning of carbon compounds e.g. wood & petroleum
• In combined state carbon dioxide occurs as:

  • As metallic carbonates & bicarbonates in the earth's crust. e.g. Magnesite MgCO3
• Allotropes of carbon -

  Crystalline form:

  • Diamond
  • Graphite
  • Fullerene

  Amorphous form:

  • Coal
  • Coke
  • Lampblack Soot
  • Charcoal - [wood, bone, sugar]
• Magnesium ribbon burns in carbon dioxide gas depositing black particles of carbon on the walls of the jar.

  $CO2 +$$2Mg -> 2MgO +$$C$
• Oxalic acid is warmed with conc. H2SO4 which acts a dehydrating agent and removes a molecule of water from oxalic acid.
• • Liquid Carbon dioxide on sudden evaporation results in freezing & formation of solid carbon dioxide that is dry ice.
  • Refrigerant for preservation of foods. Dry ice freezes & last longer than ordinary ice
• • CO2 in solution or liquid form is liberated in a device called fire extinguisher. CO2 is non-combustible, does not support combustion & heavier than air. Hence cuts out the fire.
  • Fire fighting domestic and industrial application.