Thermodynamics Systems Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which type of thermodynamic system allows both energy and matter exchange with its environment?

Closed system

Isolated system

Open system (correct)

Semi-closed system

What is an example of a closed system?

An ice cube in a plate

Air inside a balloon

Water boiling in a boiler (correct)

Water boiling in a kettle

Which type of thermodynamic system is completely sealed off from its environment?

Open system

Closed system

Isolated system (correct)

Dynamic system

In a thermodynamic process, which of the following variables is NOT typically used to describe the state of a system?

Entropy Signup and view all the answers

What happens to the internal energy of a system during a thermodynamic process?

It can change with the state of the system. Signup and view all the answers

When water in a vessel is heated and starts boiling, which of the following statements is true?

The temperature of the water increases. Signup and view all the answers

Which example illustrates an isolated system?

A sealed thermos flask with hot coffee inside. Signup and view all the answers

What distinguishes a closed system from an open system?

Closed systems exchange energy only, while open systems exchange both. Signup and view all the answers

What happens to the gas molecules when the piston is pushed in and the volume decreases?

They gain momentum from the piston. Signup and view all the answers

When a gas expands against a constant pressure of 1 atm from 5 liters to 10 liters and absorbs 400 J of thermal energy, what is the change in internal energy?

300 J Signup and view all the answers

What is the condition for a system to be in mechanical equilibrium?

The pressure throughout the system is constant. Signup and view all the answers

Which factor is NOT a characteristic property of thermodynamic state variables?

Molecular weight Signup and view all the answers

If a system releases 125 kJ of heat and 104 kJ of work is done on the system, what is the change in internal energy?

-29 kJ Signup and view all the answers

A system is said to be in chemical equilibrium when:

There is no transfer of matter due to diffusion. Signup and view all the answers

What type of thermodynamic variable does not depend on the size of the system?

Temperature Signup and view all the answers

What is required for a system to achieve thermodynamic equilibrium?

All forms of equilibrium must be satisfied Signup and view all the answers

What describes thermal equilibrium between two systems?

Both systems reach the same temperature with no heat transfer. Signup and view all the answers

What does the Zeroth Law of Thermodynamics state?

Systems in thermal equilibrium with a third system are in equilibrium with each other. Signup and view all the answers

What aspect of thermodynamics does internal energy refer to?

The energy related to disordered motion of the molecules in a system. Signup and view all the answers

What occurs when ice is placed in water at room temperature?

Heat from the water melts the ice until equilibrium is reached. Signup and view all the answers

Which of the following best describes a thermodynamic system?

A collection of objects that can share energy with their environment. Signup and view all the answers

When hot water is mixed with cold water, what happens to the hot water?

It cools down as heat is transferred to the cold water. Signup and view all the answers

What is the main function of a thermometer based on thermodynamic principles?

To detect the temperature of an object in thermal equilibrium. Signup and view all the answers

Which statement is true regarding heat transfer between two bodies?

Heat transfers from a higher temperature body to a lower temperature body. Signup and view all the answers

What describes a system in chemical equilibrium?

The system's chemical composition is constant over time. Signup and view all the answers

Which equation represents the equation of state for an ideal gas?

PV = nRT Signup and view all the answers

What does the area under the P-V curve represent?

The work done in changing the volume of the gas. Signup and view all the answers

Which of the following is true about the work done during gas expansion?

The work is positive when the volume increases. Signup and view all the answers

During gas compression in a piston-cylinder, what happens to the pressure of the gas?

The pressure increases. Signup and view all the answers

What happens to the internal energy of the gas when it is brought in contact with a heat source?

It increases due to the flow of heat towards the gas. Signup and view all the answers

Which condition leads to the gas cooling down?

The gas pushes the piston out. Signup and view all the answers

What best describes the P-V diagram for a gas expanding at constant pressure?

It appears as a line parallel to the volume axis. Signup and view all the answers

If a gas is expanding with varying pressure, what happens to the work done by the gas?

The sign of work depends on volume change direction. Signup and view all the answers

How can the internal energy of the gas be increased besides using heat?

By quickly pushing the piston to compress the gas. Signup and view all the answers

In the context of thermodynamic state variables, what term describes the mathematical relation between these variables?

Equation of state. Signup and view all the answers

In a thermodynamic system, what indicates that work is done by the gas?

The piston moves due to pressure from the gas. Signup and view all the answers

According to the First Law of Thermodynamics, how are work and heat related?

Energy can be transferred through heat and work interactions. Signup and view all the answers

What occurs to the internal energy of the gas during expansion?

The internal energy decreases as work is done by the gas. Signup and view all the answers

When does the gas experience a positive work done on it?

When it compresses against external pressure. Signup and view all the answers

What causes energy (heat) to flow from the environment to the gas?

The gas being at a lower temperature than the environment. Signup and view all the answers

What is a thermodynamic process?

A procedure by which a system transitions from an initial state to a final state. Signup and view all the answers

In the context of thermodynamic processes, what does positive work imply?

Work is done by the system on its surroundings. Signup and view all the answers

What characterizes a quasi-static system?

The system is always in thermodynamic equilibrium. Signup and view all the answers

How does heat transfer influence a thermodynamic process?

Heat may be absorbed or released, affecting system state changes. Signup and view all the answers

What happens when the piston in a cylinder is pushed in?

Positive work is done on the system. Signup and view all the answers

What is indicated by the paths on a p-V diagram during a thermodynamic process?

The series of intermediate states traversed by the system. Signup and view all the answers

What occurs during an isothermal expansion of an ideal gas?

The gas expands without changing its temperature and absorbs heat. Signup and view all the answers

What is the effect of a sudden release of gas from an insulated cylinder?

The partition break leads to uncontrolled expansion. Signup and view all the answers

Study Notes

Thermodynamics

Thermodynamics is the branch of physics that studies heat, temperature, and the interconversion of heat and other forms of energy.
It's a combination of "thermo" (heat) and "dynamics" (motion).
A vehicle's engine and muscles both do work and produce heat.

Thermal Equilibrium

When a piece of ice is placed in water at room temperature, the ice melts because heat transfers from the warmer water to the colder ice.
Similarly, hot water cools down when mixed with cold water as heat moves from the warmer entity to the cooler.
Thermal equilibrium exists when two or more objects or substances reach the same temperature and there's no net heat transfer.
Heat travels from a higher temperature to a lower temperature.
System in thermal equilibrium do not transfer heat.

Laws of Thermodynamics

Zeroth Law: If two systems are in equilibrium with a third system, they are also in equilibrium with each other. This is used to measure temperature.

Internal Energy

Every system is made up of many molecules.
Internal energy is the energy related to the random motion of molecules in a system.
A glass of water sitting on a table has internal energy although this isn't noticeable on a macroscopic scale.

Thermodynamic System

A thermodynamic system is a group of objects that can exchange energy with their surroundings.
Anything that isn't part of the system is the environment or surroundings.

Types of Thermodynamic Systems

Open system: Allows matter and energy exchange with its surroundings (e.g., water boiling in a kettle).
Closed system: Allows energy exchange but not matter exchange with its surroundings (e.g., water boiling in a sealed boiler).
Isolated system: Doesn't allow matter or energy exchange with its surroundings (e.g., a thermos flask).

Thermodynamic Process

A thermodynamic process is any procedure that modifies a system's thermodynamic state.
For example, heating water in a vessel causes changes in state variables such as temperature, pressure, and volume.
A system's state is represented by its temperature, pressure, and volume.

Change in Internal Energy of a System

Internal energy (U) can change by heat transfer or work being done.

First Law of Thermodynamics

First Law establishes a connection between work and heat, and they are related in a thermodynamic process.
Work can be done on the system or by the system, depending on volume changes.

Work in a p-V diagram

The work done by a system during a thermodynamic process can be represented graphically using the area under the p-V curve.
The area of the curve is used to calculate work, indicating if the work done on the system or by the system (positive or negative value).

Change in internal energy during a process

Internal energy change is calculated by the difference between Heat transferred and Volume-pressure work done

Thermodynamic Cycle

A thermodynamic cycle is a series of thermodynamic processes that eventually return the system to its initial state. The network done by a cycle can be calculated by integrating the area under the cycle in the p-V diagram.

Thermodynamic Equilibrium

A mechanical equilibrium exists if there are no unbalanced forces within the system and between the surroundings.
Equilibrium also exists if the pressure is similar everywhere within the system, and between the system and the surroundings.
Chemical equilibrium is when no chemical reactions occur and no diffusion of matter takes place between different parts of the system.
Thermal equilibrium is when a system has a consistent temperature throughout and this temperature does not change over time.

Thermodynamic State Variables and Equation of State

Thermodynamic state variables are measurable characteristics of a system.
Examples include pressure (P), temperature (T), volume (V), density, and more.
The mathematical relationship between state variables is called the equation of state.
The equation of state for an ideal gas is PV = nRT, where: P is pressure, V is volume, n is the number of moles of gas, R is the universal gas constant and T is temperature.

Isothermal Process

An isothermal process undergoes change with a constant temperature.
For instance melting ice is an isothermal process.

Isobaric Process

An isobaric process is a change that takes place at a constant pressure.
Example: boiling water at a constant atmospheric pressure.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge on different types of thermodynamic systems, including open, closed, and isolated systems. This quiz covers essential concepts such as energy exchange, internal energy changes, and thermodynamic processes. Perfect for students studying thermodynamics.