There rlly isn’t noooo number so what do you expect of course it would be zero. 0£
        
                    
             
        
        
        
Question
Give a definition of mixture?
Why air is called a mixture?
Answer:
mixture - substance made by combining two more different materials in such a way that no chemical reaction occurs.
Air is a mixture  because  it is composed of gases like inert gases, carbon dioxide, oxygen, nitrogen an so on. Also dust particles are present in the atmosphere so air is a mixture .
Explanation:
 
        
             
        
        
        
Answer:
1) rusting of metal is both chemical and physical change
2) black ice is an example of a physical change
Explanation:
when metal rusts, it is due to a reaction between the atoms in the metal and the atoms in the air(oxygen) or water(oxygen). When it rusts it also physically changes the look of the metal from silver to dirty brownish maroon. 
Black ice is a change in state hence it cannot be a chemical change as the original substance NO LONGER EXISTS in a chemical reaction. It is a physical change however as the ice is changing into a different state of matter.
HOPE THIS HELPS!!!
 
        
             
        
        
        
Covalent bonds but not ionic 
        
                    
             
        
        
        
Answer:
0.2598 M
Explanation:
Molarity is mol/L, so we have to convert the grams to moles and the mL to L. To convert between grams and moles you need the molar mass of the compound, which is 36.46g/mol.



Round to the lowest number of significant figures = 0.2598 M