Kc= concentration  of  product  divided  by  concentration   of  reactant
NO +  NO2  ---->  N2O3
Kc =(N2O3)  /  (No)(NO2)
Kc= ( 1.3  )/{ (3.9)(3.8) }
Kc=0.088 (  answer  B)
        
                    
             
        
        
        
Answer:
Explanation:
The crabs cannot see the plankton they eat near the ocean floor. For the crabs to see the plankton, some color of visible light would need to reach the plankton so that it can be reflected into the crabs' eyes.
 
        
                    
             
        
        
        
Pure magnesium's formula would just be Mg because all elements except for 7 nonmetals are just left alone when they are by themselves in a formula. The 7 diatomic elements( means they have to have two of them without another element attached to it aka. a subscript two after it when it's by itself) are hydrogen, nitrogen, oxygen, fluorine, chlorine, bromine, and iodine. An easy way to remember the diatomic seven is that when looking at a periodic table if you trace over them from nitrogen over to fluorine and down to iodine all of those elements are diatomic + hydrogen. 
And your unbalanced and balanced equations are correct.
(sorry I went on a tangent with the diatomic rules hopefully it will help you in the future though) 
        
             
        
        
        
Answer: It depends on the element.
Explanation: Every element has a different amount of protons in its nucleus. It is the same as its atomic number on the periodic table. For example: Hydrogen has an atomic number of 1 because it has 1 proton in its nucleus, Helium has 2, Carbon has 6, Platnium has 78, and so on... 
 
        
             
        
        
        
Explanation:
When water vapour changes to liquid water then this process is known as condensation.
For example, when lid is placed in a hot water filled pan then after sometime vapours appear on the surface of lid. When temperature of water decreases then water vapours convert into liquid form. 
Thus, we can conclude that in condensation water vapor changes to liquid water.