Question

What is the molecular formula for an alkane with 12 carbon atoms?

Short answer

The molecular formula is \( C_{12}H_{26} \).

Step-by-step solution

Understanding Alkanes

Alkanes are saturated hydrocarbons, meaning they only contain single bonds between carbon atoms. They follow a general molecular formula of \( C_nH_{2n+2} \), where \( n \) is the number of carbon atoms.

Identify the Number of Carbon Atoms

In this exercise, we are given that the alkane has 12 carbon atoms. So, we substitute \( n = 12 \) into the general formula for alkanes.

Apply the Formula

Substitute \( n = 12 \) into the general formula: \( C_nH_{2n+2} \). This gives \( C_{12}H_{2(12)+2} \).

Simplify the Formula for Hydrogen Atoms

Calculate \( 2(12) + 2 \) which simplifies to 24 + 2 = 26. Thus, the molecular formula becomes \( C_{12}H_{26} \).

Key concepts

Alkane Chemistry

Alkane chemistry is a fundamental topic in organic chemistry, revolving around the properties and reactions of alkanes. Alkanes are the simplest form of hydrocarbons, consisting only of carbon and hydrogen atoms. They are also referred to as paraffins.

• Alkanes are characterized by carbon atoms connected exclusively by single covalent bonds.
• Due to their stability, alkanes are relatively inert, meaning they don't react easily under normal conditions.
• Common uses of alkanes include fuel, lubrication, and as starting materials for more complex chemicals through reactions like cracking and reforming.

Understanding alkanes involves knowing their structure, naming them according to the International Union of Pure and Applied Chemistry (IUPAC) system, and recognizing their general physical properties, such as being less dense than water and insoluble in it.
Alkanes are typically found in natural sources like crude oil, from which they are extracted and refined for various uses in energy production and materials science.

Saturated Hydrocarbons

Saturated hydrocarbons are compounds made solely of hydrogen and carbon atoms, where all bonds between carbon atoms are single bonds. Because they contain the maximum possible number of hydrogen atoms, they are called 'saturated.'

• The term 'saturated' indicates that no more hydrogen atoms can be added without breaking the stability of carbon chains.
• Alkanes are the primary type of saturated hydrocarbons.
• The lack of carbon-carbon double or triple bonds in alkanes means they have lower reactivity compared to unsaturated hydrocarbons.

Saturated hydrocarbons are also called alkanes and exhibit notable properties, including their ability to be burned cleanly as fuels, providing energy with fewer byproducts like soot or smoke.
Their stable structure also contributes to their use as a clean choice in household or industrial settings, such as in gas stoves or internal combustion engines.

General Molecular Formula

The general molecular formula for alkanes is an essential component in understanding their composition and how their structure scales with the number of carbon atoms.

• The formula is given by \( C_nH_{2n+2} \), where \( n \) represents the number of carbon atoms in the alkane molecule.
• This formula helps predict the number of hydrogen atoms that accompany any given number of carbon atoms.

For example, determining the molecular formula of an alkane with 12 carbon atoms involves substituting \( n = 12 \) into the formula, resulting in \( C_{12}H_{26} \).
This relationship is crucial in organic chemistry as it allows chemists to derive the molecular makeup of alkane substances efficiently, predicting their possible size and interactions without needing physical observation.