Need 1. decide whether each of these reactions is exothermic or endothermic: a. when two chemicals mix their temperature rises: b. a solid burns brightly and releases heat, light and sound: c. when two chemicals are mixed their temperature drops: d. two chemicals will only react if you heat them continually: e. plants take in light energy for photosynthesis: 2. 4 fe = 3o2 → 2 fe2o3 is this equation balanced? yes / no, explain why 3. which chemical equation is balanced? 2na + cl2 → 2nacl na + 2cl2 → 2nacl 2na + 2cl2 → 2nacl na + cl2 → nacl 4. list four signs of a chemical reaction.