3. Find the mass of silver that experiences a temperature change of 7.0°C to 90.0°C with total change in heat
energy of 300.0 J.

4. Find the specific heat of 0.40 kg of graphite that changes from 26.0°C to 30.0°C and absorbs 1136 J of heat
energy

i think it's c. i'm not sure but i think so.

  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-