Chemistry

  All Class Assessment  Grade 8 Chemistry 21-22                            Class Assessment 1.     What is this symbol ' ⇌ ' used to represent? A.    dual side reaction B.    dual side process C.    reversible reaction D.    reversible process         2. When the system A + B   C + D is at equilibrium, ( a ) the forward reaction has stopped. ( b ) both the forward and the reverse reactions have stopped. ( c ) the reverse reaction has stopped. ( d ) neither the forward nor the reverse reaction has stopped.   3.     Meaning of the word "anhydrous" is A.    with water B.    without water C.    with copper D.    without copper   4.     A reaction in which liquid freezes and its solid form changes into liquid at same temperature, is called E.    dual side reaction F.    dual side process G.   reversible reaction H.    reversible process   5.     The water melts and freezes at A.    different temperatures B.    different p

All Class Assessment  Grade 7 Chemistry 21-22     All  Class Assessment    1.      ---------------------- is a natural rock a)     Element b)     Ore c)      Atom 2.      The metal in ores are chemically bonded to other ------------------ d)     Element e)     Ore f)       Atom 3.      The least reactive ones are at the ----------------- g)     tope h)     middle i)        bottom 4.      Ores are rocks from which it is economical to extract metals that they contain. A)     True B)     False 5.      The least reactive ones are at the tope A)     True B)     False   j)        Most metal are found naturally in --------------------------- called ores. A.     Element B.     rocks C.     Atom k)         Gold is very expensive because it is ----------------------to find. A.     difficult B.     easy C.     both A & B l)        ----------------  is a process of heating an ore  to a high temperature in the presence of air. middle A.     Blasting B.     Roasting C.     Melting m)   The metal