#1: which of the following statements is true? a. in an endothermic reaction, the energy of the products is the same as the energy of the reactants. b. in an endothermic reaction, the energy of the products is less than the energy of the reactants. c. in an exothermic reaction, the energy of the products is the same as the energy of the reactants. d. in an exothermic reaction, the energy of the products is less than the energy of the reactants. ***my answer; d is that right? @aaronq : )

Option (D) is the correct answer.

Explanation:

In an endothermic reaction energy is absorbed by reactant molecules in a chemical reaction as a result energy of products is more than the energy of reactants.  

Whereas in an exothermic reaction energy is released by a chemical reaction as a result energy of reactants is more than the energy of products.  

Therefore, we can conclude that the correct statement is in an exothermic reaction, the energy of the products is less than the energy of the reactants.

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.