Is this a multiple choice? Anyways I will just give you a written answer and hopefully it helps.
A: Helium is made up of two electrons held by electromagnetic force to two protons that are inside of a nucleus along with one or two neutrons.
<u>Answer:</u> The equations are provided below.
<u>Explanation:</u>
Skeleton equations are defined as the equations which simply indicate the molecules that are involved in a chemical reaction. These equations are unbalanced equations.
Balanced equations are defined as the chemical equation in which number of individual atoms on the reactant side must be equal to the number of individual atoms on the product side.
Water decomposes in the direct current to form hydrogen and oxygen.
Skeleton Equation: 
Balanced Equation: 
Mercury (II) oxide decomposes in heat to form mercury, oxygen.
Skeleton Equation: 
Balanced Equation: 
Calcium carbonate when heated forms calcium oxide and carbon dioxide.
Skeleton Equation: 
Balanced Equation: 
Group 2 hydroxides, when heated forms oxide and water vapor.
Skeleton Equation: 
Balanced Equation: 
Firstly, a balanced equation has to be written for the production of ammonia (NH₃) from hydrogen gas (H₂) and nitrogen gas (N₂):
N₂ + 3H₂ → 2NH₃
Now, the mole ratio of N₂ : NH₃ is 1 : 2 based on the coefficients of the balanced equation.
If the moles of N₂ = 2.5 moles
then the moles of NH₃ produced = 2.5 mol × 2
= 5 mol
Thus, the moles of ammonia produced when 2.5 mol of nitrogen gas is combined with excess hydrogen gas is 5 mol.
Answer:
She should suspect a Tornado.
Explanation:
Tornadoes form when warm humid air collides with cold dry air. The denser the cold air is pushed over warm air, causing an updraft. As soon as it reaches the ground a tornado is formed.