1- La masa molar es el número de moles de una sustancia que tendría una masa de 1 gramo. (2 Points)
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2- La suma del porcentaje por masa de cada elemento de un compuesto debe ser igual al 100%
(2 points)
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3- Un hidrato es un compuesto que reacciona violentamente en presencia de agua.
(2 points)
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4- Anhidro es un término que se usa para describir un compuesto que no posee moléculas de
agua enlazadas a sus átomos
(2 points)

  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-

girl imma just put my comment here because i need a couple point okurrttt

the answer is c. nacl