Chemical Formula for Propane

Propane is a hydrocarbon that belongs to the alkane family. It is commonly used as fuel for heating, cooking, and in some vehicles. Understanding propane involves knowing its chemical structure and reactions. Here is a detailed look at propane’s chemical formula and some related examples.

Chemical Formula

The chemical formula for propane is C₃H₈.

This indicates that a propane molecule consists of three carbon (C) atoms and eight hydrogen (H) atoms. The molecular structure can be represented as:

CH₃ - CH₂ - CH₃

Structural Formula

The structural formula of propane shows the arrangement of atoms within the molecule. Each carbon atom forms four bonds, and each hydrogen atom forms one bond:

    H   H   H
    |   |   |
H - C - C - C - H
    |   |   |
    H   H   H

Isomerism

Propane does not have isomers because all three carbon atoms can only connect in a single linear arrangement.

Combustion Reaction

One of the most important reactions involving propane is combustion. In the presence of sufficient oxygen, propane burns to produce carbon dioxide and water:

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O + heat

Example: Calculate the amount of CO₂ produced when 1 mole of propane is burned.

Given the balanced equation:

C₃H₈ + 5O₂ → 3CO₂ + 4H₂O

1 mole of C₃H₈ produces 3 moles of CO₂.

Uses of Propane

Propane is used in various applications, such as:

Fuel for Heating and Cooking: Propane is used in household heating systems and for cooking in gas grills and stoves.
Automotive Fuel: Propane is used as an alternative fuel for vehicles in the form of liquefied petroleum gas (LPG).
Industrial Applications: Propane is used in industrial processes, such as metal cutting and soldering.

Physical Properties

Boiling Point: -42.1°C or -43.8°F
Melting Point: -187.7°C or -305.9°F
Density: Approximately 2.0098 kg/m³ (at 0°C and 1 atm)

Chemical Properties

Non-Polar Molecule: Propane is non-polar due to the similar electronegativities of carbon and hydrogen atoms.
Flammability: Propane is highly flammable and can form explosive mixtures with air.

Example of Propane Usage

Example: A propane tank used for a barbecue grill contains 10 kg of propane. How much heat energy is released when the propane is completely burned?

Using the combustion reaction and knowing the heat of combustion of propane is approximately 50.4 kJ/g:

Heat energy = mass × heat of combustion
Heat energy = 10,000 g × 50.4 kJ/g = 504,000 kJ

Thus, 10 kg of propane releases 504,000 kJ of heat energy upon complete combustion.

Understanding the chemical formula and properties of propane is essential for its safe and effective use in various applications. Whether for heating, cooking, or industrial purposes, propane plays a vital role in our daily lives.