Ground Water can become polluted from when fossils and things make their way to the bottom of the ground and polluted the ground water
 
        
                    
             
        
        
        
Barium fluoride (BaF2) - Also known as Barium(II) fluoride - because it's a combination of two different kinds of ions (binary = two).
        
                    
             
        
        
        
Answer: 460.624
Explanation: 
1. Multiply the numbers 
(24.5260 x 2.56) + 397.84
= (62.784) + 397.84
2. Add the numbers 
(62.784) + 397.84
= 460.624
        
             
        
        
        
11. I would say physical because the color of the item is changed and the texture and density is changed aswell.