table of contents states of matter changes of state gas behavior

Solids, Liquids, and Gases

States of Matter

Changes of State

Gas Behavior

Graphing Gas Behavior

Table of Contents

Solids, Liquids, and Gases - States of Matter

Solids1. definite shape2. definite volume 3. fixed, closely packed arrangement of particles that

vibrate in place

Two types of solids:a)crystalline solid

1. regular, repeating pattern of particles.2. Melts at a specific temperature3. Ex: salt, sugar

b) amorphous solid 1. particles are arranged randomly 2. does not melt at a specific temperature 3. Ex: plastic, rubber, glass

2) liquid-a. Definite volume

b. No definite shapec. Particles move freely around one anotherd. fluid- a substance that can flow.


LiquidsBecause its particles are free to move, a liquid has no definite shape. However, it does have a definite volume.

- States of Matter

Properties of a Liquidsurface tension

1. the inward pull of molecules toward each other 2. acts like a skin 3. dependent upon the substance

Viscosity 1. Resistance to flowing. 2. high viscosity flows slowly 3. depends on the size and shape of the particles and the attraction between them.

3) gas- a. no definite shape b. no definite volume.

c. Fills the space available


GasesAs they move, gas particles spread apart, filling all the space available. Thus, a gas has neither definite shape nor definite volume.

- States of Matter


Building VocabularyA definition states the meaning of a word or phrase by telling about its most important feature or function. After you read the section, reread the paragraphs that contain definitions of Key Terms. Use all the information you have learned to write a definition of each Key Term.

Key Terms: Examples:

- States of Matter

solid A solid has a definite shape and a definite volume.crystalline solid Solids that are made up of crystals are called

crystalline solids.amorphous solid In amorphous solids, the particles are not arranged

in a regular pattern.

liquid A liquid has a definite volume but no shape of its own.

fluid A liquid is also called a fluid, meaning “a substance that flows.”

Key Terms: Examples:surface tension

viscosity

gas

Surface tension is the result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together.

Another property of liquids is viscosity—a liquid’s resistance to flowing.

Like a liquid, a gas is a fluid. Unlike a liquid, however, a gas can change volume very easily.


Viscosity

Click the Video button to watch a movie about viscosity.

- States of Matter


End of Section:States of Matter

2-2 Changes in State-occurs when its thermal energy

increases or decreases significantlymelting1. solid to

liquid2.At its melting point, the particles of a solid substance are vibrating so fast that they break free from their fixed positions.

3. Melting Point Identifies a pure substance.


Changes Between Solid and LiquidThe change in state from a solid to a liquid is called melting.

- Changes of State


freezing1. liquid to solid

2. At its freezing point, the particles of a liquid are moving so slowly they begin to form regular patterns.

3. Same temperature as the melting point.


Changes Between Solid and LiquidThe change of state from liquid to solid is called freezing.

- Changes of State

takes place when the particles in a liquid gain enough energy to form a gas. 1. Liquid --- > Gas

Vaporization

2. evaporation- vaporization that takes place on the surface of a liquid.

3. boiling- vaporization that takes place within the liquid as well as on its surface.

1). Boiling point identifies a pure substance

2). Boiling depends upon air pressureLower air pressure = lower Boiling

point

Condensation gas ---> liquid1. occurs when particles in a gas

lose enough thermal energy and form a liquid.

2. Example: Fog on a windowSublimation solid --- > gas

1. the particles of a solid do not pass through the liquid state as they form a gas.

2. Surface gains enough energy to form a gas.

3. Example: Dry Ice


1. You are stranded in a blizzard. You need water to drink, and

you’re trying to stay warm. Should you melt snow and then drink it,

or just eat snow? Explain.

You should melt snow and then drink it. If you eat snow, your body must use some of its valuable energy to change the snow to a liquid.

2. Why does the evaporation of

sweat cool your body on a warm

day?

Your body supplies the thermal energy necessary to change the sweat from a liquid to a gas, causing the body to lose heat and become cooler


Temperature and Changes of StateA beaker of ice at –10ºC was slowly heated to 110ºC. The changes in the temperature of the water over time were recorded. The data were plotted on the graph shown here.

- Changes of State


Temperature and Changes of State

Temperature (ºC) on the y-axis, time (minutes) on the x-axis

Reading Graphs:

What two variables are plotted on the graph?

- Changes of State



The temperature is rising from 0ºC to 100ºC.

Reading Graphs:

What is happening to the temperature of the water during segment C of the graph?

- Changes of State



Segment B: melting point of ice; segment D: boiling point of water

Interpreting Data:

What does the temperature value for segment B represent? For segment D?

- Changes of State



Change from solid to liquid; change from liquid to gas

Drawing Conclusions:

What change of state is occurring during segment B of the graph? For segment D?

- Changes of State



Water molecules in segment E have more thermal energy because they are at a higher temperature.

Inferring:

In which segment, A or E, do the water molecules have more thermal energy? Explain your reasoning.

- Changes of State


OutliningAs you read, make an outline about changes of state. Use the red headings for the main topics and the blue headings for the supporting ideas.

Changes in State

I. Changes Between Solid and Liquid

A. MeltingB. Freezing

II. Changes Between Liquid and Gas

A. EvaporationB. BoilingC. Boiling Point and Air

PressureD. Condensation

III. Changes Between Solid and Gas

- Changes of State


Data Sharing Lab

Click the PHSchool.com button for an activity about sharing data for the Skills Lab Melting Ice.

- Changes of State


End of Section:Changes of State


A Change in PressureA punctured basketball deflates as gas particles begin to escape.

- Gas Behavior


Using FormulasPressure can be calculated using the formula below. Force is measured in newtons (N). If area is measured in square meters (m2), pressure is expressed in pascals (Pa).

Pressure = Force/Area

For example, a machine exerts a force of 252 N on a piston having an area of 0.430 m2. What is the pressure in pascals on the piston?

Pressure = 252 N/0.430 m2 = 586 Pa

- Gas Behavior


Using FormulasPractice Problem

A trash compactor exerts a force of 5,600 N over an area of 0.342 m2. What pressure in pascals does the compactor exert?

P = 5,600 N/0.342 m2 = 16,374 Pa

- Gas Behavior


2-3 Gas BehaviorGas behavior is dependent upon 3 factors:

1) volume- the amount of space matter fills. cm3, mL, L2) temperature- a measure of the average energy of

motion particles contain. oC3) pressure- the force of its outward push divided by the

area the gas is in.Pa—pascals or kPa--kilopascals


Pressure and VolumeAs weights are added, the gas particles occupy a smaller volume. The pressure increases.

- Gas Behavior

Solids, Liquids, and GasesBoyle’s LawIf temperature is constant:

As the pressure of a gas increases, the volume decreases.

As the pressure decreases, the volume increases.

P1V1 = P2V2


Volume and TemperatureChanging the temperature of a gas at constant pressure changes the volume similarly.

- Gas Behavior

Solids, Liquids, and GasesCharles’s LawIf pressure remains constant:

As the temperature of a gas increases,

the volume increases.

As the temperature decreases, the volume decreases.

V1/T1 = V2/T2


Pressure and TemperatureWhen a gas is heated, the particles move faster and collide more often with each other and with the walls of their container. The pressure of the gas increases.

- Gas Behavior


Additional Gas Law

If the volume remains constant:As the temperature of a gas is increased,

the pressure increases.

As the temperature is decreased, the pressure decreases.


Gas Laws Activity

Click the Active Art button to open a browser window and access Active Art about gas laws.

- Gas Behavior


Questions Answers

Asking QuestionsBefore you read, preview the red headings. In a graphic organizer like the one below, ask a what or how question for each heading. As you read, write answers to your questions.

What measurements are useful in studying gases?

Volume, temperature, and pressure

How are the pressure and volume of gases related?

When the pressure of a gas increases at constant temperature, its volume decreases.

How are the pressure and temperature of gases related?

When the temperature of a gas increases at constant volume, its pressure increases.

How are the volume and temperature of gases related?

When the temperature of a gas increases at constant pressure, its volume increases.

- Gas Behavior


End of Section:Gas Behavior


Making a GraphThe x-axis (horizontal) and the y-axis (vertical) form the “backbone” of a graph.

- Graphing Gas Behavior


Temperature and VolumeAs the temperature of the water bath increases, the gas inside the cylinder is warmed by the water.



Temperature and VolumeThe data from the experiment are recorded in the notebook table.



Temperature and VolumeThe graph of Charles’s law shows that the volume of a gas is directly proportional to its kelvin temperature under constant pressure.



Pressure and VolumePushing on the top of the piston decreases the volume of the gas. The pressure of the gas increases.



Pressure and VolumeThe data from the experiment are recorded in the notebook table.



Pressure and VolumeThe graph of Boyle’s law shows that the pressure of a gas varies inversely with its volume at constant temperature.



Previewing VisualsBefore you read, preview Figure 23. In a graphic organizer like the one below, write questions that you have about the diagram. As you read, answer your questions.

Graphing Charles’s LawQ. What is the relationship between temperature and

volume?

A. The volume of a gas is directly proportional to its temperature under constant pressure.

Q. What does the dotted line show?

A. The dotted line predicts how the graph would look if the gas could be cooled further.



Links on Gases

Click the SciLinks button for links on gases.



End of Section:Graphing Gas

Behavior


Graphic Organizer

Solid Definite

Not definite Water

Not definite Oxygen

State of Matter Shape VolumeExample (at room temperature)

Liquid

Gas

Definite

Definite

Not definite

Diamond



End of Section:Graphic Organizer

table of contents states of matter changes of state gas behavior

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