Explanation:
Aquifers are porous and permeable formations that stores ground water. The ground water system is made up of mostly fresh water. 
- An aquifer acts as a reserve for ground water in the environment. 
 - By passing through different formations, water that recharges them are purified. 
 - This makes them fresh and mostly free from salt intrusion 
 
An aquifer is able to store this fresh water and it is is good prospect for sourcing ground water. 
 
        
             
        
        
        
The mass of Calcium required to complete this reaction is 4.008 g. 
- Law of conservation of mass states that In a closed system, mass cannot be produced or destroyed, but it can be changed from one form to another.
 - The mass of the chemical constituents before a chemical reaction is equal to the mass of the constituents after the reaction.
 - In several disciplines, including chemistry, mechanics, and fluid dynamics, the idea of mass conservation is widely applied.
 
In the given reaction mass of product after completion of reaction is 13.614 g that means total mass of constituents before reaction should also be 13.614.
So, 
mass of Ca + mass of O₂ + mass of S = mass of CaSO4
Ca + 6.400 g + 3.206 g = 13.614 g 
mass of Ca = 13.614 - 9.606 = 4.008 g
Therefore, by law of conservation of mass 4.008 g of Ca is required for the completion of the reaction. 
Learn more about mass conservation here:
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102 grams of ammonia is formed when 3 moles of nitrogen and 6.7 moles of hydrogen reacts. 
Explanation:
The equation given is of Haeber's process in which the nitrogen is limiting factor in the ammonia formation and hydrogen if in excess gets delimited.
We know that 1 mole of Nitrogen gives 2 moles of ammonia.
We have 3 moles of nitrogen here,
So, 6 moles of ammonia will be form
so from the formula 
no of moles=mass/atomic mass
            mass= no. of moles*atomic mass
                      = 6*17
                        = 102 grams of ammonia will be formed.
So, 6 moles or 102 grams of ammonia is formed when 3 mole of nitrogen and 6.7 mole of hydrogen reacts.
 
        
             
        
        
        
Answer:
1. 72.9 atm 
2. 0.43937 K
Explanation:
1. Gray- lussacs law is p1/t1=p2/t2 so we use this formula to figure it out by filling in the variables and solving
p1=45.0 atm
t1=323 K
p2= ?
t2=523 K 
Now we fill in this in the formula and solve - 45.0 atm/ 323 K = p2/ 523 K
and now we solve for p2 by multiplying 535k by each side to give us p2
2. Using the same formula we get 10.0atm/? = 12.0 atm/ 273.15 k and we divide both sides by 10.0 atm