What does the energy hill represent on an energy diagram? A. The potential energy gained by the products when a reaction
happens
B. The final amount of potential energy of the products of the
reaction
C. The potential energy the reactant's have stored in molecular bonds
D. The additionat potential energy the reactants must gain in order to
React

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.