Chapter 9: Heat and States of Matter

Heat Engine

: A device that converts thermal energy into work.

Evaporation

causes the temperature of the liquid to decrease.

Convection Currents

result when heated fluid rises and cooler fluid sinks.

Convection

: the transfer of thermal energy in a fluid by the movement of fluid from place to place.

Solids

usually are better thermal conductors than liquids or gases.

Temperature

: a measure of the average kinetic energy of its particles.

Thermodynamics

: The study of the relationship among thermal energy, heat, and work.

Plasma

: matter consisting of positively and negatively charged particles and does not have a definite shape or volume.

Kinetic Theory

: The motion of the particles in matter.

Entropy

: a measure of how spread out, or dispersed, energy is.

Thermal Energy Flows

A system is an open system if across the boundary or if work is done across the boundary.

Entropy Principle

: all events that occur cause the entropy of the universe to increase.

Law of Thermodynamics

First : the increase in thermal energy of a system equals the work done on the system plus the thermal energy transferred to the system.

Specific Heat

is measured in joules per kilogram per degree Celsius, which is written as J / (kg °C)

Kinetic Energy

When particles collide, can be transferred from one particle to another and the direction of particle motion changes.

Electric Heaters

convert electrical energy to thermal energy.

Thermal Insulator

: A material in which thermal energy moves slowly.

Thermal Energy

A refrigerator does work on the coolant in order to transfer from inside the refrigerator to the warmer air outside.

Evaporation

: Vaporization that occurs at the surface of a liquid.

Vaporization

occurs as liquid changes into a gas.

Liquids

have a definite volume, but not a definite shape.

Specific Heat

: The amount of thermal energy needed to raise the temperature of 1 kg of some material by 1°C.

kinetic theory

According to the , matter is composed of particles that are atoms, molecules, or ions that always are in random motion.

Thermal Energy

: The sum of the kinetic and potential energies of all the particles in an object.

Thermal Energy

always flows from a warmer to a cooler material.

Kelvin

The SI unit for temperature

Heat of Fusion

The amount of energy required to change 1 kg of a substance from a solid to a liquid at its melting point

Conduction

This transfer of thermal energy between colliding particles

Thermal Conductor

A material in which thermal energy is transferred easily

Thermal Insulator

A material in which thermal energy moves slowly

First Law of Thermodynamics

the increase in thermal energy of a system equals the work done on the system plus the thermal energy transferred to the system

Second Law of Thermodynamics

States that it is impossible for thermal energy to flow from a cool object to a warmer object unless work is done

Heat Engine

A device that converts thermal energy into work

Entropy Principle

all events that occur cause the entropy of the universe to increase