Page 220 - ICSE Chemistry 8
P. 220

•  Lampblack is a fi ne black powder prepared by burning hydrocarbons like oil, wax, kerosene oil, paraffi  n,
                       naphthalene or petrol in limited supply of air.
                    •  The diff erent varie  es of coal are peat, lignite, bituminous and anthracite.
                    •  When coal is heated strongly in the absence of air it produces coke, coal gas, coal tar and ammonia
                       solu  on.
                    •  Carbon monoxide is a highly poisonous gas and is accumulated in the atmosphere mainly when carbon
                       (charcoal) burns in the presence of insuffi  cient supply of oxygen (air).




                                                              EXERCISES



                 BE PROMPT
                 A.  Fill in the blanks.

                       1.  The compounds of carbon of biological origin are called ___________________.
                       2.  _____________ is the phenomenon of existence of an element in more than one form.

                       3.  _____________ is the purest form of carbon.
                       4.  _____________ charcoal is used to separate a mixture of noble gases.

                       5.  _____________ is a type of coke which is a black and porous substance used in household furnaces.
                       6.  Solid carbon dioxide is called _____________.


                 B. Iden  fy the error in the given statements. Circle the incorrect word and write the correct word in
                      the blank.
                       1.  Carbon has atomic number 8 and its electronic confi gura  on is (2,4).           _____________

                       2.  Carbon is soluble in all solvents.                                              _____________
                       3.  Carbon exists in four allotropic forms.                                         _____________

                       4. Frac  onal dis  lla  on is the process in which breakdown of an organic
                           substance takes place on strongly hea  ng in the absence of air.                _____________
                       5.  The higher the carbon content of coal, the lower is its calorifi c value.        _____________

                       6.  Carbon dioxide is lighter than air.                                             _____________

                 C.  Match the columns.
                          Column A                               Column B

                       1.  Polyvinyl chloride                (a)  A greyish-black, opaque substance with a metallic lustre
                       2.  Water gas                         (b)  A very small molecule made up of only 60 carbon atoms

                       3.  Graphite                           (c)  Used in the manufacturing of gun powder
                       4.  Bakelite                          (d)  Used for making pipes
                       5.  Buckminsterfullerene              (e)  A mixture of carbon monoxide and hydrogen

                       6.  Lampblack                          (f)  An insulator used to make electrical switches


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