Best Answer
C) is the best description, although a scientific theory is not necessarily a "fact". They are, however, based on evidence.
A) is complete garbage.
B) is a good description of a scientific "law"- something that predicts how a certain event will occur without explaining why this is (for instance, the law of gravity accurately describes the gravitational forces between two bodies, but does not explain why these forces are there).
D) is a scientific "hypothesis"- an explanation for an observed phenomena that is yet to be proven.
Answer:
A particle
Explanation:
Modern quantum theory holds that light has both wave-like and particle-like properties. When the length scales involved are large compared to the wavelengths of light (ex., forming images with thin lenses), the
particle nature of light dominates.
Answer:
Complete ionic: 
.
Net ionic: 
.
Explanation:
Start by identifying species that exist as ions. In general, such species include:
- Soluble salts.
- Strong acids and strong bases.
All four species in this particular question are salts. However, only three of them are generally soluble in water: 
, 
, and 
. These three salts will exist as ions:
- Each
formula unit will exist as one 
ion and one 
ion. - Each formula unit will exist as one
ion and two 
ions (note the subscript in the formula 
.) - Each formula unit will exist as one and two ions.
On the other hand, 
is generally insoluble in water. This salt will not form ions.
Rewrite the original chemical equation to get the corresponding ionic equation. In this question, rewrite , , and (three soluble salts) as the corresponding ions.
Pay attention to the coefficient of each species. For example, indeed each formula unit will exist as only one ion and one ion. However, because the coefficient of 
in the original equation is two, 
alone should correspond to two 
ions and two 
ions.
Do not rewrite the salt because it is insoluble.
.
Eliminate ions that are present on both sides of this ionic equation. In this question, such ions include one unit of and two units of . Doing so will give:
.
Simplify the coefficients:
.
It has 92 protons, 92 electrons, and 238 — 92 : 146 neutrons.
