Question

Which has a higher hydrogen-to-carbon ratio: hexane or cyclohexane?

Short answer

Answer: Hexane has a higher hydrogen-to-carbon ratio than cyclohexane.

Step-by-step solution

Write the molecular formula for hexane and cyclohexane.

Hexane is an alkane with six carbon atoms in a straight chain, and its molecular formula is C6H14. Cyclohexane is a cyclic compound containing six carbon atoms in a ring, and its molecular formula is C6H12.

Calculate the hydrogen-to-carbon (H/C) ratio for hexane.

The hydrogen-to-carbon ratio for a compound can be calculated by dividing the number of hydrogen atoms by the number of carbon atoms. In the case of hexane (C6H14), there are 14 hydrogen atoms and 6 carbon atoms. Therefore, its H/C ratio is: H/C ratio (hexane) = (Number of hydrogen atoms) / (Number of carbon atoms) = 14/6 = 7/3.

Calculate the hydrogen-to-carbon (H/C) ratio for cyclohexane.

Similarly, we can calculate the H/C ratio for cyclohexane (C6H12). There are 12 hydrogen atoms and 6 carbon atoms in cyclohexane. Thus, its H/C ratio is: H/C ratio (cyclohexane) = (Number of hydrogen atoms) / (Number of carbon atoms) = 12/6 = 2.

Compare the H/C ratios and determine which compound has a higher ratio.

Now that we have the H/C ratios for both hexane (7/3) and cyclohexane (2), we can compare them. The H/C ratio of hexane is greater than that of cyclohexane, as 7/3 > 2. Therefore, hexane has a higher hydrogen-to-carbon ratio than cyclohexane.

Key concepts

Hexane

Hexane is a simple yet significant organic compound that belongs to the class of hydrocarbons known as alkanes. This compound is characterized by a straight chain of six carbon atoms, giving it the molecular formula of \( C_6H_{14} \). In hexane, each carbon atom is bonded to the maximum possible number of hydrogen atoms under the rules of chemical bonding. This digital fingerprint of molecular composition leads us to one of the outstanding attributes of this molecule - its high hydrogen-to-carbon ratio.

• It is a linear alkane.
• Hexane is often utilized in industrial and laboratory settings, notably as a non-polar solvent.

Understanding the structure and formula of hexane is fundamental when comparing its properties to other similar compounds, like cyclohexane.

Cyclohexane

Cyclohexane is another crucial compound in the realm of hydrocarbons, recognized for its distinct ring structure. Unlike hexane, cyclohexane forms a cyclic compound, denoted by the molecular formula \( C_6H_{12} \). Its formation involves six carbon atoms connected in a closed ring, reducing the hydrogen count compared to similar alkanes without rings.

• Cyclohexane's structure results in a lower hydrogen-to-carbon ratio than linear alkanes.
• This compound finds extensive use in the production of synthetic fibers and other industrial materials.

The structural transformation from a linear to a ring form reduces the hydrogen atoms, which directly affects its hydrogen-to-carbon ratio and overall chemical behavior.

Molecular Formula

The molecular formula is a concise representation showing the number and type of atoms in a molecule. In organic chemistry, it plays a crucial role, particularly when distinguishing between different isomers like hexane and cyclohexane.

• For hexane, the molecular formula is \( C_6H_{14} \), indicating it has 6 carbon and 14 hydrogen atoms.
• In cyclohexane, the formula \( C_6H_{12} \) reflects its 6 carbon and 12 hydrogen atoms.

The molecular formulas help determine characteristics like the hydrogen-to-carbon ratio, which aids in identifying whether a compound is saturated or unsaturated, and provides insights into its potential reactions and uses in various fields.

Alkane

Alkanes are a broad group of chemical compounds consisting solely of hydrogen and carbon atoms. These compounds are saturated hydrocarbons, which means every carbon atom is linked with the maximum number of hydrogen atoms possible. Hexane is a classic example, with its straight chain structure signifying it as a member of this hydrocarbon family.

• They are denoted by the general formula \( C_nH_{2n+2} \), where \( n \) represents the number of carbon atoms.
• Alkanes are known for their relatively simple chemical behavior, often used as fuel and in organic synthesis.

Understanding alkanes is essential for grasping basic organic chemistry and understanding how structural changes can pivot a compound’s properties, as seen when comparing hexane with other isomers.

Cyclic Compound

Cyclic compounds are unique in the chemical landscape due to their ring structures. Cyclohexane is a prime example, where its six carbon atoms form a closed loop, contrasting starkly with non-cyclic alkanes like hexane.

• This cyclization results in a significant reduction in the number of hydrogen atoms bonded to carbon.
• Cyclic compounds often exhibit distinct properties, such as increased stability and reactivity compared to their linear counterparts.

The structural arrangement in cyclic compounds influences their chemical properties and applications, from stability in forming complex materials to roles in synthetic chemistry. This showcases the intricate relationship between molecular structure and functionality in chemical compounds.