Answer:
64J of energy must have been released.
Explanation:
Step 1: Data given
One reactant contains 346 J of chemical energy, the other reactant contains 153 J of chemical energy. 
The product contains 435 J of chemical energy.
Step 2:
Since the energy is conserved
Sum of energy of Reactants = Energy of Products
Sum of energy of Reactants = 346 J + 153 J = 499 J
The energy of the product = 435 J 
435 < 499 
This means energy must have been lost as heat.
Step 3: Calculate heat released
499 J - 435 J = 64 J
64J of energy must have been released.
 
        
             
        
        
        
Answer:
Green
Explanation:
Positive: A strong green color in the flame indicates the presence of halogens (chloride, bromide, iodide but not fluoride).
 
        
             
        
        
        
Melting is equivalent to freezing: a temperature when a solid become a liquid.
        
                    
             
        
        
        
Answer:
In pair NaF and H2O both compounds exibit predominantly ionic bonding.