Rachel burns a 53 gram cracker under a soda can filled with 77.2 grams of water. She took the temperature of the water before she began -- it was 6.9 degrees Celsius. After the cracker was done burning, the temperature of the water was 84.3 degrees Celsius. How many calories of heat were released by the cracker? Round your answer to one digit after the decimal point.

b

Explanation:

the answer is either b or c

  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-