(a) Hydrogen gas combines with nitrogen to form ammonia. H2(g) + N2(g) → NH3 The balanced equation for this reaction can be written as: 3H2(g) + N2(g) ...

Hydrogen gas combines with nitrogen to form ammonia:

The reaction between hydrogen gas (H2) and nitrogen (N2) to form ammonia (NH3) is a well-known example of a synthesis reaction. This reaction is commonly referred to as the Haber process, which is used to produce ammonia on an industrial scale.

The chemical equation for this reaction is:

N2 + 3H2 → 2NH3

Let's break down this equation and explain it in detail:

Reactants:
- Nitrogen (N2): Nitrogen is a diatomic molecule, meaning it exists naturally as N2. It is a colorless and odorless gas that makes up approximately 78% of the Earth's atmosphere.
- Hydrogen (H2): Hydrogen is also a diatomic molecule, existing naturally as H2. It is the lightest and most abundant element in the universe.

Product:
- Ammonia (NH3): Ammonia is a compound composed of one nitrogen atom bonded with three hydrogen atoms. It is a colorless gas with a pungent odor and serves various purposes in industry, agriculture, and household products.

Reaction:
In the reaction, one molecule of nitrogen (N2) combines with three molecules of hydrogen (H2) to produce two molecules of ammonia (NH3). This reaction is exothermic, meaning it releases heat energy.

Balancing the Equation:
To balance the equation, we need to ensure that the number of atoms of each element is the same on both sides of the equation. In this case, we have two nitrogen atoms on the left side and two on the right side, three hydrogen atoms on the left side and six on the right side, and two ammonia molecules on the right side.

To balance the equation, we need to multiply the reactants with appropriate coefficients:
- N2 + 3H2 → 2NH3

This balanced equation shows that one molecule of nitrogen reacts with three molecules of hydrogen to form two molecules of ammonia.

Overall, the reaction between hydrogen gas and nitrogen to form ammonia is an essential process in the production of ammonia, which is widely used as a fertilizer and in the manufacturing of various chemicals.