Which Of The Following Is An Extensive Property Of Matter

Which of the Following is an Extensive Property of Matter? Understanding Extensive vs. Intensive Properties

The question, "Which of the following is an extensive property of matter?" requires a fundamental understanding of the difference between extensive and intensive properties. This distinction is crucial in chemistry, physics, and materials science. This article delves deep into the concept, providing clear definitions, examples, and practical applications to help you master this essential scientific principle.

What are Extensive Properties?

Extensive properties are physical properties of matter that depend on the amount of matter present. In simpler terms, if you double the amount of a substance, the value of the extensive property will also double. These properties are additive; the total value for a system is the sum of the values for its individual parts. Think of it like this: if you combine two identical objects, the extensive properties of the combined object will be twice that of a single object.

Key Characteristics of Extensive Properties:

• Dependence on Amount: The defining feature is their direct relationship to the quantity of matter.
• Additivity: The combined property of multiple parts equals the sum of the individual properties.
• Scale-Dependent: The value changes proportionally with the scale or size of the system.

Examples of Extensive Properties:

• Mass: The amount of matter in an object. A kilogram of iron has twice the mass of half a kilogram of iron.
• Volume: The amount of space occupied by matter. Two liters of water have twice the volume of one liter of water.
• Length: The distance between two points on an object. A 10-meter rope is twice as long as a 5-meter rope.
• Weight: The force of gravity acting on an object's mass (note: weight is dependent on gravitational field strength, which makes it slightly more complex, but still generally considered extensive).
• Energy: The capacity of a system to do work or produce heat. The total energy of two identical systems is twice the energy of one system.
• Heat Capacity: The amount of heat required to raise the temperature of a substance by a certain amount. A larger sample requires more heat.
• Entropy: A measure of disorder or randomness in a system. A larger system generally has higher entropy.

What are Intensive Properties?

In contrast to extensive properties, intensive properties are independent of the amount of matter present. These properties are intrinsic to the substance itself and remain constant regardless of the sample size. If you divide a sample in half, the intensive property remains unchanged for both halves.

Key Characteristics of Intensive Properties:

• Independence of Amount: The value does not change with the quantity of matter.
• Non-Additivity: The combined property of multiple parts is not simply the sum of individual properties.
• Scale-Independent: The value remains constant regardless of the size or scale of the system.

Examples of Intensive Properties:

• Temperature: A measure of the average kinetic energy of particles in a substance. A small cup of boiling water and a large pot of boiling water both have the same temperature.
• Density: The mass per unit volume of a substance. The density of gold remains the same whether you have a gold nugget or a gold bar.
• Pressure: The force exerted per unit area. The pressure inside a balloon is the same regardless of the balloon's size (assuming constant temperature).
• Boiling Point: The temperature at which a liquid boils and turns into a gas. The boiling point of water is always 100°C at standard atmospheric pressure, irrespective of the quantity.
• Melting Point: The temperature at which a solid changes into a liquid. The melting point of ice is always 0°C at standard atmospheric pressure, regardless of the amount of ice.
• Viscosity: A measure of a fluid's resistance to flow. The viscosity of honey remains constant whether you have a teaspoon or a gallon.
• Color: The visual appearance of a substance; it doesn’t change with the amount.
• Odor: The smell of a substance; it remains the same regardless of quantity.
• Hardness: Resistance to scratching or indentation; it's intrinsic to the material.
• Refractive Index: The measure of how much light bends when passing through a substance. This is an intrinsic property of the material.

Distinguishing Between Extensive and Intensive Properties: A Practical Approach

Identifying whether a property is extensive or intensive often comes down to common sense and understanding the physical meaning of the property. Ask yourself:

• Does the value change if I increase the amount of the substance? If yes, it's likely extensive. If no, it's likely intensive.
• Can I calculate the property for a larger system by simply adding the values for smaller parts? If yes, it's extensive. If no, it's intensive.
• Is the property a ratio or a measure per unit? Properties expressed as a ratio or per unit (like density: mass/volume) are usually intensive.

Why is the Distinction Important?

The distinction between extensive and intensive properties is fundamental in several scientific fields:

• Thermodynamics: Many thermodynamic calculations rely on the relationships between extensive and intensive properties. For instance, specific heat capacity (intensive) is related to heat capacity (extensive).
• Chemistry: Understanding these properties is crucial for stoichiometry, phase diagrams, and analyzing chemical reactions.
• Materials Science: Designing new materials often involves carefully selecting substances with specific intensive properties (strength, conductivity, etc.).
• Engineering: Engineers need to understand these properties to design and build structures and machines that can withstand various forces and conditions.

Advanced Considerations:

While the distinction is generally straightforward, some properties can exhibit complex behavior. For example, the heat capacity of a substance can slightly vary with temperature or pressure, although it's predominantly considered an extensive property.

Addressing the Original Question:

The question "Which of the following is an extensive property of matter?" cannot be answered without providing the "following" list of properties. However, armed with the information in this article, you can now confidently determine whether any given property is extensive or intensive. Simply check whether it depends on the amount of matter present and exhibits additivity. If it does, it's extensive; otherwise, it's intensive.

This detailed explanation provides a solid foundation for understanding extensive and intensive properties, equipping you to confidently identify them in various scientific contexts. Remember to always consider the fundamental definition: dependence on the amount of matter present. This principle guides your understanding of these essential physical characteristics of all matter.