Physical Science 1417 Chp 4 Heat & Temperature

entropy pg 110

A thermodynamic measure of disorder is called entropy. The total entropy of the universe continually increases.

Absolute zero

Absolute zero is the lowest temperature possible, occurring when all random motion of molecules was historically projected to cease.

coherent motion

All of the particles are moving together, in coherent motion, when the external kinetic energy is considered.

Radiant energy

Radiation involves the form of energy called radiant energy, energy that moves through space.

latent heat

Since the quantity of heat associated with a phase change is not associated with a temperature change, it is called latent heat.

incoherent motion

Since there is a lack of net motion and a lack of correlation, the particles have a jumbled incoherent motion.

Solids pg 90

Solids have definite shapes and volumes because they have molecules that are nearly fixed distances apart and bound by relatively strong cohesive forces.

Adhesives

Some substances, such as glue, have a strong force of adhesion when they harden from a liquid state, and they are called adhesives.

specific heat

Specific heat of a material, which is defined as the amount of heat needed to increase the temperature of 1 gram of a substance 1 degree Celsius.

flow

The liquid molecules flow, rolling over one another as the rock pushes its way between the molecules.

external and internal

To distinguish between the energy of the object and the energy of its molecules, we use the terms external and internal energy

total internal energy

of the molecules of a body, and there is more total energy in a large tub of water than in a cup of water at the same temperature.

cool

situations in which heat is flowing from your body as cool.

energy-form conversion

(mechanical, radiant, electrical, etc.), so we say that heating is taking place.

Specific Heat

1) The initial temperature of the liquid; 2) How much liquid is in the pot; and, 3) the nature of the liquid (water or soup?).

two kings of motion that the particle of an object can have:

1) a coherent motion where they move together in step, 2) an incoherent, chaotic motion of individual particles.

"Heat as Energy Transfer"

1) a temperature difference or 2) energy-form conversions.

Phase change pg. 101

1) adding heat through a temperature difference or 2) the absorption of one of the five forms of energy, which results in heating.

This state can be changed in two ways:

1) by heat flowing into (Qin) or out (Qout) of the system, or 2) by the system doing work (Wout) or by work being done on the system (Win).

Two Heating Methods

1) from a temperature difference, with energy moving from the region of higher temperature, and 2) from an object gaining energy by way of an energy-form conversation.

Phases of Matter

1) solid, 2) liquid, and 3) gas

three kinds of major phase changes

1) solid-liquid, 2) liquid-gas, and 3) solid-gas

Convert from one temperature to the other by considering two differences in the scales.

1) the difference in the degree size between the freezing and boiling points on the two scales and 2) the difference in the values of the lower reference points.

The second law and natural process

1) the observable external energy of an object 2) the internal energy of the molecules, or particles that make up an object.

heat engine

A heat engine is a device that converts heat into mechanical energy.

molecule

A molecule is generally defined as a tightly bound group of atoms in which the atoms maintain their identity.

a quantity of heat that is not associated with a temperature change

A phase change always absorbs or releases a quantity of heat that is not associated with a temperature change.

sublimation

A phase change that takes a solid directly to a gas or vapor is called sublimation.

monatomic molecule

A single atom of helium, for example, is known as a monatomic molecule.

convection current pg 100

As the air cools, it sinks over another par of the room, setting up a circulation pattern known.

diatomic molecules

At ordinary temperatures, the atoms of oxygen, nitrogen, and other gases are paired in groups of two to form diatomic molecules.

freezing point or the melting point

Both occur at a temperature called the freezing point or the melting point, depending on the direction of the phase change.

relative pg 93

Both scales have arbitrarily assigned reference points and an arbitrary number line that indicates relative temperature changes.

condensation

Condensation is the opposite of evaporation. In condensation, more molecules are returning to the liquid state than are leaving.

Convection pg 99

Convection is the transfer of heat by a large-scale displacement of groups of molecules with relatively higher kinetic energy.

atoms

Democritus wrote that matter was empty space filled with tremendous numbers of tiny, indivisible particles called atoms.

heating and cooling describe

Describe the direction of energy flow, naturally moving from a region of higher energy to one of lower energy.

Substance

Different materials require different amounts of heat to go through the same temperature range when their masses are equal.

evaporation

Evaporation reduces a volume of liquid water as water molecules leave the liquid state to become water vapor in the atmosphere. In evaporation, more molecules are leaving the liquid state than are returning.

Gases

Gases are composed of molecules with weak cohesive forces acting between them.

plasmas

Gases that are made up of positive ions and negative electrons are called plasmas.

total internal energy

Heat, on the other hand, is based on the total internal energy of the molecules of a body.

Heat Defined

Heat: Heat is a measure of the internal energy that has been absorbed or transferred from one body to another.

compounds

In addition to the chemical elements, there are pure substances called compounds that have more complex units of structure.

conducted

In solids, this transfer takes place as heat is conducted from a warmer place to a cooler one.

indirect solar gain

Indirect solar gain home uses a massive wall inside a window that serves as a storage mass.

Internal energy

Is the total kinetic and potential energy of the molecules of an object.

External energy pg 95

Is the total potential and kinetic energy of an everyday-sized object.

isolated solar gain

Isolated solar gain home uses a structure that is separated from the living space to collect and store solar energy.

average kinetic energy

It is the average kinetic energy that is proportional to the temperature, which involves the molecular mass as well as the molecular velocity.

Equation

JQ - W = U2 - U1

Key terms pg 111 British thermal unit pg 96 calorie Celsius scale p 92 conduction p 98 convection 99 entropy 110 external energy p 95 Fahrenheit scale p 92 first law of thermodynamics p 107 heat p 95 internal energy p 95

Kelvin scale p 93 kilocalorie p 96 kinetic molecular theory p 88 latent heat of fusion p 102 latent heat of vaporization p 102 molecule p 89 phase change p 101 radiation p 100 second law of thermodynamics p 208 specific heat p 97 temperature p 90

molecule

Kinetic molecular theory, the term molecule has the additional meaning of the smallest, ultimate particle of matter than can exist.

Internal potential energy

Latent heat refers to the "hidden" energy of phase changes, which is energy (heat) that goes into or comes out of internal potential energy.

fluids

Liquids and gases are collectively called fluids because of their ability to flow, a property that is lacking in most solids.

Liquids

Liquids have molecules that are not confined to an equilibrium position as in a solid.

Molecule defined

Molecule is defined as the smallest particle of a compound or a gaseous element that can exist and still retain the characteristic properties of that substance.

remains pg 102

More and more liquid water appears as the ice melts, but the temperature remains at 0 degrees C even through heat is still being added at a constant rate.

surroundings pg 107

Once the system is identified, everything else is called the surroundings.

kilocalorie

One kilocalorie (kcal) is the amount of energy ( or heat) needed to increase the temperature of 1 kilogram of water 1 degree Celsius.

British thermal unit

The English system's measure of heating is called the (Btu). One Btu is the amount of energy (or heat) needed to increase the temperature of 1 pound of water 1 degree Fahrenheit.

Fahrenheit scale

The Fahrenheit scale was developed by the German physicist Gabriel D. Fahrenheit (1686 - 1736) in about 1715.

diffuse

The ammonia molecules diffuse, or spread, throughout the room.

Mass

The amount of heat needed is also proportional to the amount of the substance being heated.

Temperature change

The amount of heat needed is proportional to the temperature change.

Adhesion

The attractive force between unlike molecules is called adhesion.

Atoms

The basic assumption of the kinetic molecular theory is that all matter is made up of tiny, basic units of structure called atoms.

metallic

The bimetallic (bi = tow; metallic = metal) strip will bend toward the metal with less expansion when the strip is heated.

thermodynamics pg 106

The branch of physical science called thermodynamics is concerned with the study of heat and its relationship to mechanical energy, including the science of heat pumps.

degrees

The distance between the two reference points was then divided into equal intervals called degrees.

kinetic molecular theory

The experiments finally led to a collection of assumptions about the small particles of matter and the space around them. Collectively, the assumptions could be called the kinetic molecular theory.

thermometer

The human body is a poor sensor of temperature, so a device called a thermometer is used to measure the hotness or coldness of something.

heat involved in a solid-liquid phase change in melting or freezing.

The latent heat of fusion is the heat involved in a solid-liquid phase change in melting or freezing.

the heat involved in a liquid-gas phase change where there is evaporation or condensation.

The latent heat of vaporization is the heat involved in a liquid-gas phase change where there is evaporation or condensation.

joule

The metric unit for measuring work, energy, or heat is the joule.

calorie

The metric unit of heat is called the calorie (cal). A calorie is defined as the amount of energy (or heat) needed to increase the temperature of 1 gram of water I degree Celsius.

The second law of thermodynamics pg 108

The natural direction of this process is called the second law of thermodynamics, with is that heat flows from objects with a higher temperature to objects with a cooler temperature.

true relative

The numbers simply mean some measure of temperature relative to the freezing and boiling points of water under normal conditions.

process

The process of increasing the internal energy is called heating, and the process of decreasing internal energy is called cooling.

latent heat of vaporization

The quantity of heat (Q) absorbed or release during this phase change is called the latent heat of vaporization (Lv).

latent heat of fusion

The quantity of heat (Q) is absorbed without a temperature change, it is called the latent heat of fusion.

coherent motion, heating, incoherent motion defined:

The relationship is that work on an object is associated with its coherent motion, while heating an object is associated with its internal incoherent motion.

condensation point

The temperature at which a gas or vapor changes back to a liquid is called the condensation point.

boiling point

The temperature at which a liquid boils and changes to a gas (or vapor) is called the boiling point.

vapor

The term vapor is sometimes used to describe a gas that is usually in the liquid phase.

Radaiton

The third way that heat transfer takes place because of a temperature difference is called radiation.

average kinetic energy

The word average implies that some of the molecules have a greater energy and others have less.

Process:

The word process is italicized to emphasize that heat is energy that can be measured as energy flows into or out of an object.

centigrade scale

There are 100 equal intervals, or degrees, between these two reference points, so the Celsius scale is sometimes called the centigrade scale.

elements

There are similar groups of atoms that make up the pure substances known as chemical elements.

internal energy

Thermodynamics is concerned with the internal energy (u) the total internal potential and kinetic energies of molecules making up a substance, such as the gases in the simple heat engine.

conduction

This is called conduction, the transfer of energy from molecule to molecule.

Kelvin Scale

This is not a relative scale but an absolute temperature scale called the Kelvin scale.

absorbs

This means that every gram of ice that melts in your cooler absorbs 80.0 cal of heat.

thermal motion

This random, chaotic motion is sometimes called thermal motion.

quad

This unit is the quad, which is 1 quadrillion Btu (a million billion or 10 15 Btu).

working

Thus, heating by energy-form conversion is actually a transfer of energy by working.

some amount of energy

Thus, the escaping molecules absorb energy from the surroundings, and condensing gas (or vapor) releases the exact same amount of energy.

Celsius scale

Was invented by Anders C. Celsius (1701-1744), a Swedish astronomer, in about 1735.

Phase change

When a solid, liquid, or gas changes from one phase to another, the transition is called:

Temperature

When a temperature difference occurs, energy is transferred from a region of higher temperature to a region of lower temperature.

how hot or how cold something is

When people ask about the temperature, they are really asking how hot or how cold something is.

equals & saturated

When the condensation rate equals the evaporation rate, the air above the liquid is said to be saturated.

Cohesion

When this attractive force is between the same kind of molecules, it is called;

external kinetic

When you push a table across the floor, the observable external kinetic energy of the table is transferred to the

temperature

Whether the kinetic energy is jiggling, vibrating, rotating, or moving from place to place, the temperature of a substance is a measure of the average kinetic energy of the molecules making up the the substance.

The first law of Thermodynamics

Which states that the energy supplied to thermodynamic system in the form of heat, minus the work done by the system, is equal to the change in internal energy.

warm

You sense situations in which heat is flowing into your body as warm and situations in which heat is flowing into your body as warm and

direction

Your body judges temperature on the basis of the net direction of energy flow

relative

Your response, or feeling, about the referent or number depends on a number of factors, including a relative comparison.

direct solar gain pg 103

direct solar gain home is one in which solar energy is collected in the actual living space of the home.

internal kinetic

internal kinetic energy of the molecules tween the table legs and the floor, resulting in a temperature increase.