50 ! brainliest if

which is usually associated with a faster reaction rate?
a. adding heat energy to the reactants
b. putting a glass cover over the reactants
c. using a solid with a low surface area in the reactants
d. decreasing the concentration of a solution of the reactants

A is the answer because the others don't make sense. B if you put glass over reactants it doesn't change anything in the reaction. C using a solid with a low surface area will actually be doing the opposite, a higher SA will increase the rate of reaction. D decreasing the concentration will decrease the reaction

  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-