SECOND LAW OF THERMODYNAMICS | 10.4

Kelvin statement

It impossible to remove thermal energy from a system at a single temperature and convert it to mechanical energy without changing the system or surroundings in some other way.”

Clausius statement:

Heat cannot, by itself, pass from a colder to a warmer body.

Heat Engine

device that converts internal energy into a more useful form such as mechanical and electrical energy

HOT reservoir

1. Heat is absorbed from a ******

Mechanical

****** work is done in heat engine

COLD reservoir

Heat is given off to a *******

impossible

It is **** to construct a heat engine that, operating in a cycle, produces no other effect than the absorption of energy from a reservoir and the performance of an equal amount of work

Heat engine statement:

It is impossible to extract an amount of heat QH from a hot reservoir and use it all to do work W . Some amount of heat QC must be exhausted to a cold reservoir.

Refrigerator or Heat Pumps

a heat engine operating in reverse

reversible procese

n which every state along some path is an equilibrium state / are an idealization, but some real processes are good approximations

irreversible process

does not meet these requirements

never the reverse

Heat flows spontaneously from hotter to colder bodies,

Refrigerator” Statement:

It is impossible for a refrigerator working in a cycle to produce no other effect than the transfer of thermal energy from a cold object to a hot object!”

Carnot Engine

A theoretical engine developed by Sadi Carnot ►A heat engine operating in an ideal, reversible cycle (now called a ***** between two reservoirs is the most efficient engine possible

Entropy

***** can be described in terms of disorder ►A disorderly arrangement is much more probable than an orderly one if the laws of nature are allowed to act without interference.

negative and entropy decreases.

When energy is absorbed, Q is

positive and entropy increases

When energy is absorbed, Q is

disorder

Isolated systems tend toward greater **** , and entropy is a measure of that disorder

perpetual motion machine

would operate continuously without input of energy and without any net increase in entropy.

Perpetual motion machines of the first type would violate the ****** , giving out more energy than was put into the machine

First Law

Second

Perpetual motion machines of the second type would violate the **** Law, possibly by no exhaust.