Which Of The Following Is Not An Intensive Property

Which of the Following is NOT an Intensive Property? Understanding Intensive vs. Extensive Properties

The distinction between intensive and extensive properties is fundamental in physics and chemistry. Understanding this difference is crucial for various applications, from thermodynamics to material science. This article will delve deep into the concept, explore examples of both intensive and extensive properties, and definitively answer the question: which of the following is NOT an intensive property (assuming a multiple-choice question is presented). We'll also touch upon how this understanding impacts various scientific fields.

What are Intensive Properties?

Intensive properties are characteristics of a system that are independent of the amount of matter present. In simpler terms, they don't change even if you increase or decrease the size of the sample. Think of it like this: if you take a sample and divide it in half, the intensive properties of each half will remain the same as the original sample.

Key Characteristics of Intensive Properties:

• Independent of mass or size: The most defining characteristic.
• Intrinsic to the substance: They reflect the inherent nature of the material.
• Useful for identification: Intensive properties are often used to identify and characterize substances.

Examples of Intensive Properties:

• Temperature: The temperature of a cup of water is the same as the temperature of a swimming pool filled with the same water, assuming they are in thermal equilibrium.
• Pressure: The pressure of a gas in a small container is the same as the pressure of the same gas in a larger container, assuming the temperature remains constant.
• Density: The density of gold is the same whether you have a gold nugget or a gold bar.
• Boiling point: The boiling point of water remains 100°C (at standard atmospheric pressure) regardless of the volume of water.
• Melting point: Similar to boiling point, the melting point is an intensive property.
• Refractive index: This measures how light bends when passing through a material; it's independent of the material's quantity.
• Color: The color of a substance doesn't change based on the amount present.
• Hardness: A diamond's hardness remains the same regardless of its size.
• Specific heat capacity: The amount of heat required to raise the temperature of 1 gram of a substance by 1 degree Celsius.

What are Extensive Properties?

Extensive properties are characteristics of a system that depend on the amount of matter present. If you increase the amount of matter, the extensive property will also increase proportionally. Conversely, if you decrease the amount of matter, the extensive property will decrease proportionally.

Key Characteristics of Extensive Properties:

• Dependent on mass or size: Their value directly relates to the amount of substance.
• Additive: The values for multiple parts of a system can be added together to find the total value for the whole system.

Examples of Extensive Properties:

• Mass: The mass of 1 kg of iron is significantly less than the mass of 10 kg of iron.
• Volume: The volume of 1 liter of water is smaller than the volume of 10 liters of water.
• Length: A 10-meter rope is longer than a 1-meter rope.
• Energy: The total energy of a system is the sum of the energies of its components.
• Heat capacity: This is the total amount of heat needed to change a substance's temperature; it increases with the mass of the substance.
• Number of moles: This depends on how much of the substance you have.

Distinguishing Between Intensive and Extensive Properties: A Practical Approach

The easiest way to distinguish between intensive and extensive properties is to consider whether halving the sample size would change the property's value. If the value remains the same, it's an intensive property; if it's halved, it's an extensive property.

How to Answer "Which of the Following is NOT an Intensive Property?"

To answer this type of question, you need a multiple-choice list of properties. Let's consider a hypothetical example:

Question: Which of the following is NOT an intensive property?

A. Density B. Temperature C. Volume D. Refractive Index

Solution:

• Density (A): Intensive. Density remains constant regardless of sample size.
• Temperature (B): Intensive. The temperature of a system is independent of its size.
• Volume (C): Extensive. Volume directly correlates with the amount of substance.
• Refractive Index (D): Intensive. This optical property remains unchanged regardless of sample size.

Therefore, the correct answer is C. Volume.

Applications of Intensive and Extensive Properties in Different Fields:

The understanding of intensive and extensive properties is paramount in various scientific and engineering fields:

• Thermodynamics: Intensive properties are crucial in defining the state of a thermodynamic system. For instance, temperature and pressure are used to describe the state of a gas.
• Material Science: Intensive properties like density, hardness, and melting point are used to characterize and identify different materials.
• Chemical Engineering: In chemical processes, intensive properties help to design and control reactions. For example, knowing the boiling point of a solvent is crucial for designing distillation processes.
• Fluid Mechanics: Intensive properties such as density and viscosity are essential parameters in analyzing the behavior of fluids.

Beyond the Basics: Specific Heat Capacity – An Intensive Property with a Subtlety

While specific heat capacity is typically considered an intensive property (because it relates the heat required to change the temperature of one gram of a substance), the total heat capacity of an object is extensive. This highlights that even seemingly simple properties can have nuances depending on how they are defined and measured. This distinction lies in the normalization: specific heat capacity normalizes for mass, making it independent of the amount of substance, while total heat capacity does not.

Advanced Concepts: Molar Properties

Many extensive properties can be converted into intensive properties by dividing them by the amount of substance (often expressed in moles). These are called molar properties. For example, molar volume is the volume occupied by one mole of a substance, and molar mass is the mass of one mole of a substance. These molar properties are useful for comparing the properties of different substances on a per-mole basis.

Conclusion:

The distinction between intensive and extensive properties is crucial for a comprehensive understanding of physical and chemical systems. While it might seem like a basic concept, its applications are far-reaching. By understanding the fundamental difference and how to apply this knowledge, you can effectively analyze and interpret data in various scientific and engineering fields. Remembering that extensive properties scale with the amount of substance while intensive properties remain constant regardless of the amount is the key to correctly identifying intensive properties and solving related problems. The next time you encounter a question asking which property is NOT intensive, you will be well-equipped to accurately identify the extensive property from the list.