What evidence is there that Potential energy is entering the system

Particle model to predict what will happen if a sharp object creates a hole in the soccer ball

650.j is the same amount of energy as? 2720cal1550cal650.cal2.72cal

Butane gas reacts with oxygen gas to give carbon dioxide gas and water vapor (gas). if you mix butane and oxygen in the correct stoichiometric ratio, and if the total pressure of the mixture is 390 mmhg, what is the pressure (in mmhg) of water vapor after the reaction is completed (temperature and volume do not change).