Answer:
because hard water is salty
The answer is the third one .
Answer:
a) No molecules of hydrogen
b) four molecules of ammonia
c) four left molecules of nitrogen.
Explanation:
The balanced reaction between nitrogen and hydrogen molecules to give ammonia molecules is:

Thus one molecule of nitrogen will react with three molecules of hydrogen to give two molecules of ammonia.
We have six molecules of each nitrogen and hydrogen in the closed container and they undergo complete reaction it means the limiting reagent is hydrogen. For six molecules of nitrogen, eighteen molecules of hydrogen will be required.
So six molecules of hydrogen will react with two molecules of nitrogen to give four molecules of ammonia.
The product mixture will have
a) No molecules of hydrogen
b) four molecules of ammonia
c) four left molecules of nitrogen.
1) 100s of millions of years ago Trees and plants fall into swamps
2) Layers of rotting plant matter builds up underwater
3) Over millions of years the weight of layers heat the plant matter and turn into Peat
4) Over millions of years more pressure and heat turns Peat into coal