First you should know that there is seven oxygen atoms in one Mn2O7
So 
2.00 moles of Mn2O7 contain 14.00 moles of oxygen...
Then you multiply this no. with Avagadro no....
from formula
Number of moles= no. of particles/avagadro's no..
14.00×6.02×10²³=84.28 atoms of oxygen... 
        
             
        
        
        
Answer:
The answer is D because NH4+and OH- it will be 
N-1. N-1,
 H-5
O-1 H-5
 O-1
 
        
             
        
        
        
Answer:
Hello fellow brainlian! here is the answer that you seek:High pressure areas are usually caused by air masses being cooled, either from below (for instance, the subtropical high pressure zones that form over relatively cool ocean waters to the west of Califormia, Africa, and South America
Explanation:
Have a totally horse-some day!
                    With love, 
                             -The one and only Alaska
 
        
                    
             
        
        
        
Could you show the characteristics?