145 since it’s the mass number plus protons I think
        
                    
             
        
        
        
Answer:
The easiest way to identify a double displacement reaction is to check to see whether or not the cations exchanged anions with each other.
Explanation:
 if the states of matter are cited, is to look for aqueous reactants and the formation of one solid product (since the reaction typically generates a precipitate).
 
        
             
        
        
        
Answer:
0.48
Explanation:
all you need is to decide 12% with 100% then you multiply it by 4L. 
 
        
             
        
        
        
Answer:
0.5 mole
Explanation:
The question isn't even clear 
But I'm guessing you want to ask the number of moles
n= Number of molecules/ Avogadros number 
n= 1/2
 
        
             
        
        
        
Answer:
The number is mostly related to the mass or the weight of the element. 
Explanation: