Liquid nitrogen is a very cold fluid form of nitrogen that is capable of freezing objects in very short periods of time. In fact, if a ping pong ball is placed in liquid nitrogen for a few minutes and then dropped on the floor, it shatters like glass. What type of changes does the ball experience when it is frozen in the liquid nitrogen and then dropped on the floor?
A.
physical changes only
B.
neither physical nor chemical changes
C.
physical and chemical changes
D.
chemical changes only

plz don't give wrong asnwer

  the   balanced   equation   for   reaction of   ca metal   with   o2 to   produce   cao   is as below

2 ca+ o2→ 2 cao2

  explanation

the reaction is   balanced     since the   number of atoms   in reactant side is   equal to   number of atoms   in   product side.   for   example   they   are 2   atom of   ca in   reactant   side   and   2   atoms of ca   in   the product side.

  the   process   is a   meet the   requirement   of   redox   reaction because :     calcium   is   oxidized   from   oxidation state 0   to 2+   while   oxygen   is reduced from   oxidation   state   0   to 2-

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