During an experiment, a metal and an excess of fluorine gas were placed into a combustion chamber at a temperature of 1800°C. The temperature in the sealed chamber continued to rise to 2100°C. After the reaction stopped, a brittle white substance, which dissolved in water, was extracted from the chamber. What can be concluded from this evidence?
- exothermic formation reaction
- endothermic decomposition reaction
- exothermic decomposition reaction
- endothermic formation reaction