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Chapter 3 Solids, Liquids, and Gases
Table of ContentsChapter Preview
3.1 States of Matter
3.2 Changes of State
3.3 The Behavior of Gases
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
1. The space that matter fills is called
a. pressure.
b. area.
c. volume.
d. mass.
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
1. The space that matter fills is called
a. pressure.
b. area.
c. volume.
d. mass.
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
2. Which of the following describes a solid?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
2. Which of the following describes a solid?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
3. Which of the following describes a liquid?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
3. Which of the following describes a liquid?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
4. Which of the following describes a gas?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Chapter Preview Questions
4. Which of the following describes a gas?
a. definite volume but no definite shape
b. definite shape and definite volume
c. neither definite shape nor definite volume
d. definite shape but no definite volume
Chapter 3 Solids, Liquids, and Gases
Section 1:States of Matter
California Content Standard 8.3.e: Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.
Chapter 3 Solids, Liquids, and Gases
Solids
The particles in a solid are closely locked in position and can only vibrate.
Chapter 3 Solids, Liquids, and Gases
Solids
Solids that are made up of crystals are called crystalline solids.
In amorphous solids, the particles are not arranged in a regular pattern.
Chapter 3 Solids, Liquids, and Gases
Liquids
Compared to particles in a solid, the particles in a liquid are more loosely connected and can collide with and move past one another.
Chapter 3 Solids, Liquids, and Gases
Gases
In gases, the atoms and molecules are free to move independently, colliding frequently.
Chapter 3 Solids, Liquids, and Gases
Section 2:Changes of State
California Content Standard 8.3.d: Students know the states of matter (solid, liquid, gas) depend on molecular motion.
California Content Standard 8.5.d: Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction.
Chapter 3 Solids, Liquids, and Gases
Changes Between Solid and Liquid• The change in state from a solid to a liquid is called melting. • When a substance melts, the particles in the solid vibrate so
fast that they break free from their fixed positions.• A change from solid to liquid involves an increase in thermal
energy.
Chapter 3 Solids, Liquids, and Gases
Changes Between Solid and Liquid• The change from a liquid to a solid is called freezing.• When a substance freezes, the particles in the liquid
move so slowly that they begin to take on fixed positions.
• The change from liquid to solid involves a decrease in thermal energy.
Chapter 3 Solids, Liquids, and Gases
Changes Between Liquid and Gas• The change from a liquid to
a gas is called vaporization.
• Vaporization that takes place only on the surface of a liquid is called evaporation.
Chapter 3 Solids, Liquids, and Gases
Changes Between Liquid and Gas• Boiling occurs when a liquid
changes to a gas below its surface as well as at the surface.
• The temperature at which a liquid boils is called its boiling point.
• The boiling point of a substance depends on the pressure of the air above it.
• The lower the pressure, the less energy needed for the particles of the liquid to escape into the air.
• Boiling point is a characteristic property of a substance.
Chapter 3 Solids, Liquids, and Gases
Changes Between Liquid and Gas
Condensation •The change in state from a gas to a liquid.•During condensation, the particles in a gas lose enough thermal energy to form a liquid.•Condensation is the reverse of vaporization.•Clouds in the atmosphere form due to condensation.
Chapter 3 Solids, Liquids, and Gases
Changes Between Liquid and Gas
Sublimation •During sublimation, particles of a solid do not pass through the liquid state as they form a gas.•Dry ice, or solid carbon dioxide, is an example of compound that does not turn to liquid at normal atmospheric pressures.
Chapter 3 Solids, Liquids, and Gases
Temperature and Changes of State
A beaker of ice at –10ºC was slowly heated to 110ºC. The graph shows how the temperature of the water changed over time.
Chapter 3 Solids, Liquids, and Gases
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?
Chapter 3 Solids, Liquids, and Gases
Temperature and 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?
Chapter 3 Solids, Liquids, and Gases
Temperature and 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?
Chapter 3 Solids, Liquids, and Gases
Temperature and 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? During segment D?
Chapter 3 Solids, Liquids, and Gases
Section 3:The Behavior of Gases
California Content Standard 8.3.d: Students know the states of matter (solid, liquid, gas) depend on molecular motion.
California Content Standard 8.9.e: Construct appropriate graphs from data and develop quantitative statements about the relationships between variables.
Chapter 3 Solids, Liquids, and Gases
Measuring GasesWhen working with a gas, it is helpful to know its volume, temperature, and pressure.
Volume
Temperature
Because gas particles move and fill the space available, the volume of a gas is the same as the volume of its container.
Temperature is a measure of the average energy of motion of the particles of matter. The faster the particles are moving, the greater their energy and the higher the temperature.
Chapter 3 Solids, Liquids, and Gases
Measuring Gases
When working with a gas, it is helpful to know its volume, temperature, and pressure.
Pressure
Pressure of a gas is the force of its outward push divided by the area of the walls of the container.
Pressure is often measured in units of pascals (Pa) or kilopascals (kPa). It can also be measured in atmospheres (atm) or millimeters of Mercury (mm Hg).
Chapter 3 Solids, Liquids, and Gases
A Change in Pressure
A punctured basketball deflates as gas particles begin to escape.
Chapter 3 Solids, Liquids, and Gases
Temperature and Volume – Charles’s LawWhen the temperature of a gas increases at constant pressure, its volume increases.
The variables are directly proportional to each other, forming a straight line that passes through the origin.
Chapter 3 Solids, Liquids, and Gases
Temperature and Volume – Charles’s Law
When the temperature of a gas is decreased at constant pressure, the volume decreases.
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Charles’ LawTemperature Conversion
Equation
Kelvin (K) = °C + 273
Example: 0 °C = 273 K
20 °C = 293 K
V1/T1 = V2/T2
V1 = Volume 1
T1 = Temperature 1
V2 = Volume 2
T2 = Temperature 2
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Charles’ LawExample 1:
Calculate the decrease in temperature when 2.00 Liters of gas at a temperature of 20 °C is compressed to 1.00 Liters.
V1/T1 = V2/T2 20 °C = 293 Kelvin
2 L = 1L
293 K x
2x = 293
x = 146.5 Kelvin
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Charles’ Law
Example 2:
Calculate the increase in volume when 600 mL of air at a temperature of 20 °C is heated to 60 °C.
V1/T1 = V2/T2 20 °C = 293 Kelvin
60 °C = 333 Kelvin
600 mL = x
293 K 333 K
293x = (600)(333)
293x = 199,800
x = 682 mL
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Charles’ Law
Example 3: Check for Understanding
A gas occupies 900 mL at a temperature of 27 °C. What is the volume at 132 °C?
V1/T1 = V2/T2 27 °C = 300 Kelvin
132 °C = 405 Kelvin
900 mL = x
300 K 405 K
300x = (900)(405)
300x = 364,500
x = 1,215 mL
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Charles’ Law
Example 4: Check for Understanding
What change in volume results if 60 mL of gas is cooled from 33 °C to 5 °C?
V1/T1 = V2/T2 33 °C = 306 Kelvin
5 °C = 278 Kelvin
60 mL = x
306 K 278 K
306x = (60)(278)
306x = 16,680
x = 54.5 mL
Chapter 3 Solids, Liquids, and Gases
Pressure and Volume – Boyle’s Law
When the pressure of a gas at constant temperature is increased, the volume of the gas decreases.
Chapter 3 Solids, Liquids, and Gases
Pressure and Volume – Boyle’s Law
When the pressure is decreased, the volume increases.
Gas pressure is inversely proportional to volume at constant temperature. The product of the two variables is a constant.
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Boyle’s LawPressure Conversion
Equation
1 atm = 760 mm Hg = 101,325 Pa
Example: 2 atm = 1,520 mm Hg
2 atm = 202,650 Pa
(P1)(V1) = (P2)(V2)
P1 = Pressure 1
V1 = Volume 1
P2 = Pressure 2
V2 = Volume 2
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Boyle’s Law
Example 1:
A gas occupies 12.3 liters at a pressure of 40 mm Hg. What is the volume when the pressure is increased to 60 mm Hg?
(P1)(V1) = (P2)(V2)
(12.3)(40) = (60)(x)
492 = 60x
x = 8.2 liters
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Boyle’s Law
Example 2:
If a gas occupies 3.60 liters at a pressure of 1 atm, what will its volume be at a pressure of 2.50 atm?
(P1)(V1) = (P2)(V2)
(1)(3.60) = (2.50)(x)
3.60 = 2.50x
x = 1.44 liters
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Boyle’s Law
Example 3: Check for Understanding
If a gas occupies 1.56 liters at a pressure of 1 atm, what will its volume be at a pressure of 3 atm?
(P1)(V1) = (P2)(V2)
(1)(1.56) = (3)(x)
1.56 = 3x
x = .52 liters
Chapter 3 Solids, Liquids, and Gases
Gas Law Problems – Boyle’s Law
Example 4: Check for Understanding
If a gas occupies 600 mL at a pressure of 8 atm, what will its volume be at a pressure of 2 atm?
(P1)(V1) = (P2)(V2)
(8)(600) = (2)(x)
4,800 = 2x
x = 2,400 mL
Chapter 3 Solids, Liquids, and Gases
Pressure and Temperature
When 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.
Chapter 3 Solids, Liquids, and Gases
Graphing Gas Behavior
In an experiment, the temperature of a gas at a constant volume was varied. Gas pressure (in kilopascals) was measured after each 5-kelvin change in temperature. The data from the experiment are shown in the table.
Chapter 3 Solids, Liquids, and Gases
Graphing Gas BehaviorGraphing
Use the data to make a line graph. Plot temperature on the horizontal axis with a scale from 270 K to 300 K. Plot pressure on the vertical axis with a scale from 0 kPa to 25 kPa. (1 kPa = 1,000 Pa)
Chapter 3 Solids, Liquids, and Gases
Graphing Gas Behavior
Changing the temperature of a gas at constant volume changes its pressure in a similar way.
Interpreting Data
What was the manipulated variable in this experiment?
Chapter 3 Solids, Liquids, and Gases
Graphing Gas Behavior
Pressure increases with temperature.
Interpreting Data
What kind of trend do the data show?
Chapter 3 Solids, Liquids, and Gases
Graphing Gas Behavior
Gas pressure increases.
Drawing Conclusions
What happens to the pressure of a gas when temperature is increased at constant volume?