Answer:
1
all matter is made of tiny particles called atom
An endothermic chemical reactions products tend to have a higher potential energy than the reactants. Thus making the /\ H positive, not negative.
Answer and Explanation:
As the temperature of the substances increases, the average energy of the molecules increases, and average energy of attraction between the molecules decreases consequently intermolecular spacing between the molecules increases. As a result, a substance change in succession from gas to liquid to solid.
Answer:
They aren't listed as a whole number, because an atom's mass is not always a whole number. The mass differs between types of atoms as well.
