Question

Among the following, the intensive property is (properties are) A) molar conductivity B) electromotive force C) resistance D) heat capacity

Short answer

The intensive properties among the given options are A) molar conductivity and B) electromotive force.

Step-by-step solution

Understanding Intensive Properties

Intensive properties are those properties of a system that do not depend on the system's mass or the amount of substance present. These properties remain the same regardless of the size of the system.

Analyzing Each Option

Review each provided property to determine whether it is dependent on the size or amount of substance in a system. Molar conductivity refers to conductivity per mole and is therefore independent of mass. Electromotive force (emf) is a potential difference and does not depend on the amount of substance. Resistance depends on the dimensions of the material but is not an extensive property per se. Heat capacity depends on the amount of substance.

Identifying Intensive Properties

From the review, both molar conductivity and electromotive force are independent of the amount of substance, making them intensive properties. Resistance is not fundamentally extensive or intensive as it can change with size and shape of the object. Heat capacity is an extensive property because it depends directly on the amount of substance present.

Key concepts

Molar Conductivity

Molar conductivity, often represented as \(\Lambda_m\), is a key concept in physical chemistry that signifies the conducting power of all the ions produced by dissolving one mole of an electrolyte. It is measured in Siemens meter squared per mole (S m\(^2\) mol\(^{-1}\)). Unlike other properties that change with the amount of substance, molar conductivity is intensive because it gives us the conductivity of a solution based on a per mole basis.

When discussing molar conductivity, it's important to understand that it varies with the concentration of the electrolyte. It typically increases with dilution, as the ions have more room to move. This property is vital when discussing electrolyte solutions and is often tested in competitive exams like JEE Advanced physics, where a clear grasp of electrolysis and its principles can give students an edge.

Electromotive Force

Electromotive force (emf) is another intensive property, crucial in the study of physics and chemistry. It is the energy provided by a cell or a battery per coulomb of charge that passes through the battery, measured in volts (V). The emf is not a force but a potential difference; think of it as a 'pressure' that drives the charge around a circuit.

Despite the name, emf does not depend on the amount of substance or the size of the battery. A larger battery does not necessarily mean a higher emf. This concept often ties into discussions on circuits, where understanding the role of emf can make complex problems much simpler. For JEE Advanced physics aspirants, mastering emf is crucial to tackle questions involving circuits and energy transformations within them.

Physical Chemistry

Physical chemistry is the branch of chemistry focused on understanding the physical properties of molecules, the forces that act upon them, and the energy changes that occur during chemical reactions. It bridges a gap between physics and chemistry by employing principles from both disciplines to delve into the physical essence of chemical systems.

Key aspects of physical chemistry include thermodynamics, quantum chemistry, and kinetics, often requiring clear conceptual understanding and mathematical prowess. Students preparing for competitive exams like JEE Advanced must be adept at applications of physical chemistry, such as calculating molar conductivity and understanding the factors affecting electromotive force.

JEE Advanced Physics

The Joint Entrance Examination (JEE) Advanced is a highly competitive exam in India for students aspiring to enter prestigious engineering institutions like the IITs. Physics is a significant part of this exam, encompassing a wide range of topics from mechanics to modern physics.

In the context of JEE Advanced physics, intensive properties like molar conductivity and electromotive force are important concepts. Questions may involve applying principles from these topics to solve problems on electrolytic cells or batteries in electric circuits. A deep understanding of intensive and extensive properties can help students classify and approach physical chemistry problems efficiently, often saving precious time during the exam.