Write the balance equation and the reaction type when magnesium is added to HCl

2HCl + Mg ==> MgCl2 + H2

Looks like a single replacement reaction to me. Mg replaced H2.

When a covalent bond is formed between 1 mole of atoms A and 1 mole of atoms B, the overall energy of these atoms decreases and heat is released into the surroundings.

i. Is the process of a covalent bond formation exothermic or endothermic?
ii Is the change of enthalpy for the formation at constant pressure of a mole of covalent bonds between A and B positive or negative? Why?

To write the balanced equation and determine the reaction type when magnesium (Mg) is added to hydrochloric acid (HCl), we need to follow a few steps:

Step 1: Write the chemical formula for the reactants.

The chemical formula for magnesium is Mg, and for hydrochloric acid, it is HCl.

Step 2: Determine the products formed.

When magnesium reacts with hydrochloric acid, it undergoes a single displacement reaction, where the magnesium displaces the hydrogen in the hydrochloric acid. So, the products formed will be magnesium chloride (MgCl2) and hydrogen gas (H2).

Step 3: Write the balanced equation.

To balance the equation, we need to make sure that there are an equal number of atoms on both sides of the equation. Here's the balanced equation:

Mg + 2HCl → MgCl2 + H2

Step 4: Identify the reaction type.

The reaction between magnesium and hydrochloric acid is a single displacement reaction, also known as a redox (oxidation-reduction) reaction. In this reaction, magnesium loses electrons (oxidation) to form Mg2+ ions, while hydrogen gains electrons (reduction) to form H2 molecules.

So, the balanced equation and the reaction type when magnesium is added to HCl can be summarized as follows:

Balanced equation: Mg + 2HCl → MgCl2 + H2
Reaction type: Single displacement (redox) reaction