The correct answer that would best complete the given statement above would be option A. Chemical changes ALWAYS <span>involve the breaking and making of chemical bonds. When there is chemical change, a new compound is being formed. If a new compound is not formed, then it is not considered as a chemical change. When a new compound is formed, therefore, there is the breaking and making of chemical bonds. Hope this helps.</span>
Answer:
D It must be equal to 1.00
Explanation:
The refraction in the second medium must be equal to 1. The refraction index is given as the ration of the angle of incidence to the angle of refraction. This is given as a fraction. In other words:

where Θ₁ and Θ₂ are angles of incidence an refraction, and n is the refractive index.
At a critical angle, the refraction is equal to the reflection inside the medium. This results in a phenomenon called total internal reflection where light is reflected internally in the medium.
Answer : The balanced molecular equation will be:

Explanation :
Molecular equation : It is a balanced chemical reaction in which the ionic compounds are expressed as the molecules instead of component ions.
According to the question, when iron react with copper (II) sulfate then it react to give iron (II) sulfate and copper as a product. In this reaction, iron is more reactive metal than the copper metal. So, it can easily displace copper metal form the solution.
The balanced molecular equation will be:

It is OH- (hydroxide ion)