Question

When propane undergoes dehydrogenation, what is the product? Name it and draw a structural formula.

Short answer

When propane undergoes dehydrogenation, the product is propene with the molecular formula \(C_3H_6\) and the structural formula: ``` H H \ / C=C \ CH3 ```

Step-by-step solution

Determine the molecular formula of propane

Propane is an alkane with the molecular formula \(C_3H_8\).

Remove hydrogen atoms for dehydrogenation

Dehydrogenation means losing hydrogen atoms. From propane, we remove two hydrogen atoms, which will result in a molecular formula of \(C_3H_6\).

Identify the product of the dehydrogenation reaction

Since propane has lost two hydrogen atoms, the resultant molecule will have a double bond between two carbon atoms. This makes it an alkene. The product of this dehydrogenation reaction is propene, which has the molecular formula \(C_3H_6\).

Draw the structural formula of the product

The structural formula of propene is: ``` H H \ / C=C \ CH3 ``` In conclusion, when propane undergoes dehydrogenation, the product is propene with the molecular formula \(C_3H_6\) and the given structural formula.

Key concepts

Alkane to Alkene Transformation

Transitioning from an alkane to an alkene is a fundamental concept in the study of organic chemistry. Alkanes are saturated hydrocarbons, meaning they contain only single bonds between carbon atoms and possess the maximum number of hydrogen atoms possible for their molecular framework. The general formula for alkanes is \(C_nH_{2n+2}\).

Alkenes, on the other hand, are unsaturated hydrocarbons characterized by at least one double bond between carbon atoms, which reduces the number of hydrogen atoms compared to alkanes. This results in the general formula \(C_nH_{2n}\) for alkenes.

The process of converting an alkane to an alkene is known as dehydrogenation. It involves the removal of hydrogen atoms from the alkane, which leads to the formation of a carbon-carbon double bond. This reaction requires the introduction of energy, typically in the form of heat, and sometimes the presence of a catalyst to enhance the reaction rate.

Key Steps of Dehydrogenation

• Select an alkane as the starting material.
• Apply heat or a catalyst to the alkane to initiate dehydrogenation.
• Remove a pair of hydrogen atoms to form the alkene with a double bond.

In educational settings, understanding this transformation is pivotal for students as it lays the groundwork for more advanced aspects of chemical synthesis and organic reaction mechanisms.

Propene Chemical Structure

The chemical structure of propene exemplifies the features of alkenes. As the dehydrogenation product of propane, propene consists of three carbon atoms and six hydrogen atoms, with a molecular formula of \(C_3H_6\). The key structural element that distinguishes alkenes like propene from alkanes is the presence of a carbon-carbon double bond.

In propene, the double bond is located between the first and second carbon atoms. The double bond is not only crucial for the compound's chemical properties but also for its reactivity. It is where chemical reactions often occur, making propene a versatile starting material for various organic syntheses.

Visualizing the Chemical Structure

• The first carbon is doubly bonded to the second carbon.
• The first and second carbons each have two hydrogen atoms attached.
• The third carbon is single-bonded to the second and carries three hydrogen atoms, forming a methyl group (\(-CH_3\)).

When depicted in drawings, molecular models, or chemical formulas, understanding the structure aids students in visualizing molecular geometry and predicting the outcomes of chemical reactions involving propene.

Chemical Reactions in Organic Chemistry

Grasping the various types of chemical reactions that occur in organic chemistry is essential for students to progress in the field. Organic chemistry revolves around the reactions of organic compounds, primarily those containing carbon-hydrogen bonds.

These reactions are not only relevant for academic study but also for practical applications such as pharmaceuticals, materials science, and energy production. Dehydrogenation, the process we've discussed in reference to transforming propane into propene, is just one category among many reaction types.

Notable Reaction Types in Organic Chemistry

• Addition reactions, where atoms or groups are added to unsaturated molecules.
• Substitution reactions, where one group replaces another group on a molecule.
• Elimination reactions, where atoms or groups are removed from molecules, typically resulting in unsaturation.
• Rearrangement reactions, where molecular structures change as a result of shifting bonds.
• Redox reactions involving the transfer of electrons between species.

In these reactions, factors such as the molecular structure, the presence of functional groups, reaction conditions (e.g., heat, pressure, catalysts), and the medium (solvent) play pivotal roles in determining the products formed.