How many moles of HCl can be made from 6.15 \(\mathrm{mol}\) \(\mathrm{H}_{2}\) and an excess of \(\mathrm{Cl}_{2} ?\)

Stoichiometry is the study of the quantitative aspects of chemical reactions. It allows us to predict the amount of product that can be formed from given reactants or the amount of reactants needed to form a desired product. In this exercise, stoichiometry helps us determine how many moles of hydrochloric acid (HCl) can be produced from a certain amount of hydrogen (H₂) when there is an excess of chlorine (Cl₂). By understanding the stoichiometric relationships between reactants and products in a chemical reaction, we can accurately calculate amounts, ensuring efficient and effective use of materials in chemical processes.

Chemical reactions involve the transformation of reactants into products. They are represented by chemical equations that show the substances involved and their quantities. In the given exercise, the chemical reaction between hydrogen (H₂) and chlorine (Cl₂) to produce hydrochloric acid (HCl) is described by the equation:


H₂ + Cl₂ → 2 HCl

This equation illustrates that one molecule of hydrogen reacts with one molecule of chlorine to produce two molecules of hydrochloric acid. Understanding this reaction helps us identify the required reactants and predict the amount of product formed, which is crucial for practical applications in chemistry.

A balanced chemical equation has the same number of atoms for each element on both sides of the equation, ensuring that mass is conserved. For the reaction between hydrogen (H₂) and chlorine (Cl₂) to form hydrochloric acid (HCl), the balanced equation is:

H₂ + Cl₂ → 2 HCl

This balanced equation signifies that the reaction starts with one molecule of H₂ and one molecule of Cl₂, resulting in two molecules of HCl. Balancing equations is essential for stoichiometry because it provides the exact relationships between reactants and products, enabling accurate calculations in chemical reactions.

The mole ratio is derived from the coefficients of a balanced chemical equation and indicates the relationship between the amounts of reactants and products. In this exercise, the balanced equation:

H₂ + Cl₂ → 2 HCl

shows a 1:1:2 mole ratio. This means that 1 mole of H₂ reacts with 1 mole of Cl₂ to produce 2 moles of HCl. Knowing the mole ratio allows us to use stoichiometry to calculate how many moles of one substance will react with or be produced from a given amount of another substance. For example, if we start with 6.15 moles of H₂, and chlorine is in excess, we can expect to produce:

Moles of HCl = 6.15 moles of H₂ * 2 = 12.3 moles of HCl
It helps us accurately determine the quantities involved in chemical reactions.