Is Boiling Point An Intensive Property: Detailed Facts


An intensive property is a property of matter that does not change by changing the configuration and quantity of matter. Is boiling point an intensive property too?

The boiling point is the temperature at which the liquid starts boiling and changes its state in the gaseous form of matter. The boiling point of a liquid does not change even if we reduce the quantity of the liquid thus it is an intensive property.

Why is the Boiling Point an Intensive Property?

The boiling point of the liquid depends upon the heat energy acquired by the liquid to break the intermolecular bonding between the atoms.

The boiling temperature of any liquid does not change even if the container shape, its size, and the quantity of a liquid kept for boiling changes. The boiling point of all the liquid is fixed in this pure form thus the boiling point is an intensive property of liquids.

is boiling point an intensive property
Water at its boiling point; Image Credit: Pixabay

You must have noticed that if you keep one liter of water for boiling or 1000 liters of water for boiling, the water will start boiling at the same temperature which is 100 degrees Celsius. The boiling point of the water does not change, it remains the same. Hence the boiling point is said to be an intensive property of liquids.

Is the Boiling Point of Water an Intensive Property?

Intensive properties of matter are such as temperature, specific heat, density, hardness, colour, transparency, refractive index, etc.

The boiling point is the temperature at which the liquid start boiling and is an intensive property of liquid as the boiling point of the liquid doesn’t change by varying the quantity of the liquid.

There are two different types of properties, intensive and extensive. Extensive properties are those which describe the physical quantity of matter like shape, size, amount, etc., unlike intensive property which does not depend upon the physical quantities.

How does the liquid turn into a vapour state upon boiling?

The molecules in the liquid are bonded by forming loosely intermolecular bonds between the atoms that they constitute.

The heat energy acquired by the volume of liquid upon boiling is grasped by these bonds. As this energy acquired is high enough to break the bonds between the atoms, the molecular bonds break, and the intermolecular spacing between the atoms increases, thus converting liquid into the gaseous phase.

The boiling point of the liquid is based on the intermolecular bonding between the molecules constituting the liquid and the number of hydrogen bonds formed. The hydrogen and oxygen atoms form a strong atomic bonding and a huge amount of energy is required to break this bond. Thus such liquids constituting the hydrogen and oxygen bond will have a high boiling point compared to other liquids.

What does the boiling point of a liquid clarify?

The boiling point is the temperature at which the liquid starts boiling and changes its phase from liquid to vapour.

Different liquids are made up of different chemical composition forming bonds with a different element and thus requires a different amount of energy to break these bonds.

Accordingly, the boiling point of the liquids differs and can tell about the chemical bonding between the molecules. Based on the boiling point we can tell about the chemical composition of the matter and estimate the bonding and chemical configuration of the matter.

What is boiling point elevation?

The elevation is a rise in quantity. The elevation of the boiling point implies a raising in the temperature.

The boiling point elevation is the rise in the temperature above the boiling point of the liquid at which the liquid starts boiling due to the addition of solute to the solvent.

It is given by the formula [latex]\Delta T=iK_bm[/latex]

Where [latex]K_b[/latex] is molal boiling point constant which is 0.510 C/m for water

[latex]\Delta T [/latex] is a change in boiling point on the addition of solute

M is a molality of solution which is defined as moles of solute dissolved per kg of solvent and

I is Van’t Hoff factor which is a number of ions formed on dissociation in the solvent.

You must have noticed that, upon adding sugar to the water, the boiling temperature of the water goes high. This is because the heat energy supplied to the volume of water is also acquired by the molecules of sugar. Moreover, the density of water also increases on dissolving the sugar in water.

Frequently Asked Questions

What is the change in the boiling point of ethanol on adding 2.5 grams of vanillin to the 75 grams of ethanol? Kb=1.220 C/m and the molar mass of vanillin is 152g/mol.

Given: [latex]K_b=1.22^0\ C/m[/latex]

M=152 g/mol

Mass of solvent = 75 grams

Mass of solute = 2.5 grams

mol of solute = [latex]\frac{2.5}{152}=0.01645\ g/mol[/latex]

[latex]Molality = \frac{mol\ of\ solute }{kg\ of\ solvent}= \frac{0.01645}{0.075} =0.22\ mol/kg[/latex]

[latex]\Delta T=iK_bm[/latex]

[latex]=1.22\times 0.22=0.2684^0C[/latex]

Hence the boiling point of ethanol on adding vanillin is [latex]78.5^0C+0.2684^0C=78.77^0C[/latex].

Why volume is not an intensive property?

Volume is a quantity defining the amount of matter present in the system and is a scalar quantity.

The volume of the matter does not remain the same throughout and can be changed by either transforming into another phase or by some external agencies and changing the container or compressing, thus it is an extensive property.

What is the difference between intensive and extensive properties?

Both these properties tell about the quantity and quantity of matter.

Intensive properties of matter are those which tend to remain fixed and do not vary while the extensive properties are those which depend upon the quantity and configuration of the matter.

Is surface tension intensive or extensive property?

The surface tension is the ability of the liquid to occupy the least surface area possible.

The surface tension between the molecules of the specific liquid does not changes as the quantity of the matter change hence it is an intensive property of matter.

Is specific gravity an intensive or extensive property of matter?

The specific gravity is a scalar quantity of matter which is the ratio of the density of the substance to the density of water at a specific pressure and temperature conditions.

Since the density is a mass of matter occupying the unit volume of matter, and the value of specific gravity is fixed for a respective matter into consideration hence it is an intensive property of matter.

Why mass is not an intensive property?

The mass of matter is based on the amount of matter present.

The amount of matter may change and can be defined based on the quantity of matter present in the container therefore it is an extensive property of matter.

Also, please click to know about Is Boiling Point And Condensation Point The Same.

AKSHITA MAPARI

Hi, I’m Akshita Mapari. I have done M.Sc. in Physics. I have worked on projects like Numerical modeling of winds and waves during cyclone, Physics of toys and mechanized thrill machines in amusement park based on Classical Mechanics. I have pursued a course on Arduino and have accomplished some mini projects on Arduino UNO. I always like to explore new zones in the field of science. I personally believe that learning is more enthusiastic when learnt with creativity. Apart from this, I like to read, travel, strumming on guitar, identifying rocks and strata, photography and playing chess. Connect me on LinkedIn - linkedin.com/in/akshita-mapari-b38a68122

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