MODEL 4: ENERGY AND CHEMICAL REACTIONS When a car coasts down a hill, the potential energy it had initially gradually becomes kinetic energy: energy the car has by virtue of its motion. To stop the car, the brakes are used to turnthe kinetic energy into thermal energy, or heat. 16. When a car that has rolled down hill is stopped with the brakes, does energy move from the air to the car or the car to the air? Explain. 17. In the figure above, which is higher in energy, reactants or products? veactants 18. When the reaction occurs, is energy consumed by the reactants or given off