What is the difference between a Lewis dot symbol and a Lewis structure?
2 H2 (g) + O2 (g) 2 H2O (g) Endothermic or exothermic Exothermic heats going out *note that combustion reactions are ALWAYS exothermic The heat energy released or absorbed by a reaction is called the heat of reaction or the enthalpy change and is represented by the symbol ∆H. Reactions tend to occur if there is an overall release of energy during the reaction. Being exothermic (∆H is negative because the reaction is losing energy by dumping heat into the surrounding) is one way that a reaction can release energy. Endothermic reactions have a positive ∆H they absorb energy 2C 2 6(g) + 7O 2(g) 4CO 2g) + 6H 2 (g) ∆H = 682.5 kcal Is this reaction exothermic or endothermic Exothermic ∆H is negativereleases heat How much heat energy (in kcal) is produced w
