Question

Hydrogen iodide gas breaks down into hydrogen gas and iodine gas during a decomposition reaction. Write a skeleton equation for this reaction.

Short answer

The skeleton equation for the decomposition reaction of hydrogen iodide gas into hydrogen gas and iodine gas is: \(HI \rightarrow H_{2} + I_{2}\).

Step-by-step solution

Identify the reactant and products

The given reactant is hydrogen iodide gas (HI). During the decomposition reaction, it breaks down into hydrogen gas (H2) and iodine gas (I2).

Write the skeleton equation

Now we'll write the skeleton equation, which represents the decomposition reaction. The reactant, hydrogen iodide gas, is placed on the left side, and the products, hydrogen gas and iodine gas, are placed on the right side, separated by an arrow: \(HI \rightarrow H_{2} + I_{2}\)

Final Step: Completed Skeleton Equation

The completed skeleton equation representing the decomposition reaction of hydrogen iodide gas into hydrogen gas and iodine gas is: \(HI \rightarrow H_{2} + I_{2}\)

Key concepts

Decomposition Reactions

A decomposition reaction is a type of chemical reaction where one compound breaks down into two or more simpler substances. Imagine it as the reverse of a combination reaction. In a decomposition reaction, a single compound acts as a reactant and forms multiple products. This is akin to unpacking a box to find several individual items inside.

Decomposition reactions typically require energy, which could be in the form of heat, light, or electricity, to initiate the breakdown of the compound. This is because bonds within the compound need to be broken. The general form for a decomposition reaction can be expressed as:

\[ AB ightarrow A + B \]

where \(AB\) is the compound and \(A\) and \(B\) are the products formed. It's essential to recognize that in decomposition reactions, the complexity of the compounds decreases as they transform into simpler molecules or atoms.

Hydrogen Iodide

Hydrogen iodide, with the chemical formula \(HI\), is a diatomic molecule composed of hydrogen (H) and iodine (I). It exists as a gas under standard conditions and is known for its strong, pungent odor. In the context of chemical reactions, hydrogen iodide is often involved in various processes, such as synthesis and decomposition.

In its gaseous form, hydrogen iodide is highly soluble in water, and its aqueous solution is known as hydroiodic acid. When thinking of hydrogen iodide in decomposition reactions, it breaks down into its constituent elements, hydrogen gas \(H_2\) and iodine gas \(I_2\).

Both hydrogen gas and iodine gas are essential in various chemical processes. Hydrogen gas, in particular, is a colorless and odorless gas, considered environmentally friendly as it produces water when it combusts. Iodine gas is a violet gas and is primarily used in medicinal and industrial applications. Understanding the behavior and properties of hydrogen iodide is key in predicting and writing its chemical reactions.

Skeleton Equation

A skeleton equation is a way to represent a chemical reaction by showing just the formulas of the reactants and products. It's like a framework or a draft before balancing the equation. The skeleton equation gives a clear indication of what substances are involved in a reaction, but it does not provide the quantities in which they react or are produced.

In the skeleton equation for a decomposition reaction, you list the reactants on the left side of an arrow and the products on the right side. For the decomposition of hydrogen iodide, the skeleton equation is:

\[ HI \rightarrow H_{2} + I_{2} \]

Here, hydrogen iodide is shown breaking down into hydrogen gas and iodine gas. The arrow signifies the direction of the reaction, from reactants to products. To make this equation a complete and balanced chemical equation, you would ensure that the number of each type of atom is the same on both sides of the equation. However, as a skeleton equation, it serves the purpose of outlining the reaction structure without focusing on stoichiometry.