Answer:
i think the answer is A....
Explanation:
Igneous rocks (from the Latin word for fire) form when hot, molten rock crystallizes and solidifies. The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface.
 
        
             
        
        
        
Sulphate ion is used but fornyour kind information there ain't no place
        
                    
             
        
        
        
Answer:
This formula contains 12 oxygen atoms.
 
        
             
        
        
        
Convert 72g of water into moles of water using molecular weights. 
So water is H2O so add up those molecular weights (H=1 and O=16)
2(1)+(16) = 18 g/mol
Then convert so 72g / (18 g/mol) = 4 mol
Now you can convert mol of water to mol of oxygen. So 4 mol of water is 4 mol of oxygen. Then use oxygen molecular weight to find grams again. 
4 mol oxygen * 16 g/mol = 64g of oxygen
If we were doing hydrogen instead of oxygen there would be 8 mol hydrogen in 4 mol of water (2 H’s in every H2O molecule) and since we have 74 grams and oxygen is 64 grams, Hydrogen should be 8 grams. Math to check below 
8 mol hydrogen * 1 g/mol = 8g of hydrogen 
It all adds to 72 so we are correct.