Physical Properties of Alkane Compounds in Organic Chemistry

Physical properties such as melting point, boiling point, viscosity, densities, colour, states at room temperature of alkanes are explained. Variation of physical properties of different alkane compounds are discussed in this tutorial.

Content - physical properties of alkane compounds

• Which will decide physical properties of alkane compounds
• Melting and boiling points of alkanes
  • List of melting and boiling points of alkanes
• Physical states (Solid, liquid, gas phases) of alkanes with comparison
• Density of alkane compounds
• Viscosity of alkane compounds

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Which will decide physical properties of alkane compounds?

Most of the physical properties of alkane compounds such as other chemicals depends on the strength of intermolecular forces between alkane molecules and molecular mass.

Melting and boiling points of alkanes

Melting and boiling points of alkanes is a significant physical property of alkane because alkanes are heavily used in industrial applications for energy generation purposes.

• There are only week Van der Waals forces between alkane molecules. Therefore, melting and boiling points of simple alkane compounds such as methane, ethane, propane, butane have lower melting and boiling points.
• When molecular mass increases, melting and boiling points increases.

List of melting and boiling points of alkanes

According to the above table, you can observe melting and boiling points gradually increase with the increment of number of carbon atoms.

Physical states (Solid, liquid, gas phases) of alkanes with comparison

As explained in the melting and boiling point comparison, physical states of alkanes also depend on the intermolecular forces and molecular mass. First alkane compounds are gases. Then number of carbon atoms is increased, next alkane compounds become liquids. Alkanes with higher molecular masses become solids.

• Physical state of alkane compound can be decided by observing the melting and boiling points of respective compound.
• As an example, let's consider butane and pentane. Butane is a gas at room temperature and Pentane is a liquid at 1 atm pressure conditions.

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Density of alkane compounds

Density is also an important physical property because alkanes in liquid form are widely used as solvents. Most of the alkanes in liquid form have density lower than water. Therefore, these liquid form alkane compounds float on water.

Densities of alkane which exist in liquid forms at room temperature

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Viscosity of alkane compounds

Viscosity of alkane which exist in liquid forms at room temperature

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Questions

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