Answer:
Iron is the densest out of the given options.
Explanation:
Oxygen
1.429 g/L
Water
1000 g/L
Hydrogen Peroxide
1450 g/L
Iron
7874 g/L
Iron Oxide
5240 g/L
 
        
             
        
        
        
Answer : The technology that can make coal a cleaner fuel is to use lower quality of coal with high sulfur content.
Explanation : Using lower quality of coal with high amount of sulfur in it can make coal a cleaner fuel because of high amount of sulfur it will have better combustion.  
        
             
        
        
        
A word equation is a written description of a chemical reaction.
All word equations start with the reactants.
Then, what comes next is the word "react to form."
Finally, the products of the equation are mentioned.
An example is,
Zinc and Hypochondriac acid react to form hydrogen gas and zinc chloride.
        
             
        
        
        
Noble Gas. Metals have 1 or 2 Valence Electrons. Halogens have 7 Valence Electrons. Semi-Metals can have different amounts.