How is coal extracted from mountaintop removal mines?
a.
dynamite is used to create underground tunnels where miners go to extract the coal.
b.
dynamite is used to break apart rocks and then draglines are used to remove the broken rock and reach the coal.
c.
coal in mountaintops is extracted by digging strips in the landscape to reach the coal.
d.
placer deposits in mountain river bottoms are removed by sifting through sediment.

The correct answer is B.

Mountain top removal is a method of surface mining, which is used to extract minerals from the surface ridge of mountains. In order to reach the minerals [usually coal] beneath the mountains, dynamites are often used to break apart the rocks, drag lines are then used to remove the split rocks in order to reach the mineral beneath. This method is a controversial method because of the damages it causes to the natural land forms.

n+h→nh3

we must remember that nitrogen and hydrogen are both diatomic molecules in their standard gas form. this adjusts the equation to

n2+h2→nh3

now we need to adjust coefficients in order to balance the atoms on each side of the equation. currently we have 2 atoms of nitrogen and 2 atoms of hydrogen on the reactant side and 1 atom of nitrogen and 3 atoms of hydrogen on the product side.

we can balance the hydrogens by placing a coefficient of 2 in front of ammonia and a coefficient of 3 in front of the hydrogen.

n2+3h2→2nh3

this gives us 6 hydrogen on each side and coincidentally the nitrogens now equal 2 on each side.