Question

Candle wax is a mixture of hydrocarbons, one of which is an alkane with 23 carbon atoms. What is the formula for this hydrocarbon?

Short answer

The formula for the alkane with 23 carbon atoms is C23H48.

Step-by-step solution

Determining the General Formula for Alkanes

The general formula for an alkane is CnH(2n+2), where 'n' represents the number of carbon atoms in the molecule.

Substituting the Number of Carbon Atoms

For the alkane with 23 carbon atoms, substitute 'n' with 23 in the general formula: CnH(2n+2) to get the molecular formula.

Calculating the Number of Hydrogen Atoms

Perform the substitution: C(23)H(2*23+2) to calculate the number of hydrogen atoms in the molecule.

Writing the Molecular Formula

After performing the calculation, the number of hydrogen atoms is 2*23+2. The molecular formula for the hydrocarbon with 23 carbon atoms is C23H48.

Key concepts

General Formula for Alkanes

Alkanes are the simplest family of hydrocarbons, compounds composed solely of carbon and hydrogen atoms. The general formula for alkanes is an essential piece of knowledge for understanding organic chemistry. It is represented as \( C_nH_{2n+2} \), where \( n \) stands for the number of carbon atoms in the molecule.

In the context of the exercise, we are asked to determine the formula for an alkane that has 23 carbon atoms. By applying the general formula for alkanes, we would insert 23 for \( n \) to compute the number of hydrogen atoms. This simplifies to \( C_{23}H_{46+2} \) or \( C_{23}H_{48} \), thereby indicating that this particular alkane molecule has 23 carbon atoms and 48 hydrogen atoms.

Understanding the general formula is crucial as it lays the foundation for predicting the molecular structure of alkanes based on the number of carbon atoms. It helps in grasping the proportional relationship between carbon and hydrogen, which is characteristic of the alkane series.

Hydrocarbons

The term hydrocarbon is used to describe compounds that consist exclusively of the elements hydrogen and carbon. Alkanes are one of the primary types of hydrocarbons, categorized for their single bonds and maximum hydrogen capacity. This makes them saturated hydrocarbons.

Hydrocarbons are the backbone of organic chemistry, and they are classified into different groups based on their structure and bonding. Alongside alkanes, there are other types, such as alkenes with double bonds and alkynes with triple bonds. Hydrocarbons have various applications, including use as fuels, solvents, and as raw materials in the plastics industry.

In our exercise, candle wax is mentioned as a hydrocarbon mixture, indicating that it’s largely made up of different types of hydrocarbons, predominantly alkanes because they are stable, non-reactive, and have high energy content, which makes them suitable for combustion.

Chemical Nomenclature

Chemical nomenclature is a systematic method for naming chemical substances. It provides a standard way to convey detailed information about the structure and composition of a molecule. The International Union of Pure and Applied Chemistry (IUPAC) sets the rules for naming compounds.

For alkanes, the IUPAC nomenclature uses prefixes based on the number of carbon atoms, followed by the suffix '-ane' indicating the molecule is an alkane. For instance, methane (\( CH_4 \)) is the simplest alkane with one carbon atom, whereas the compound in our exercise is an alkane with 23 carbon atoms. Following IUPAC rules, it should be named tricosane.

Understanding chemical nomenclature is vital for students as it aids in identifying and differentiating between the vast array of chemical compounds. Knowing the nomenclature rules allows students to both name a compound from its structure and deduce the structure from its name.