Chapter 14, Section 1

Chapter 14, Section 1

Section 1: Matter and Thermal Energy

Essential Questions

• What is the kinetic theory of matter?

• How do particles move in the different states of matter?

• How do particles behave at the boiling and melting points?

Presentation Expectations

• You do not need to write this down, you have access to the slides so you can write them down after the presentation is over. 

• For now, just listen. If you have questions, there are built-in question breaks. Write your questions down and un-mute yourself to ask the question. 

• The chat will not be monitored during the presentation, so please refrain from asking questions there. 

• Answering questions in the presentation is a requirement - if you are not responding to the questions in the Quizizz, I will assume you are not here. 

Kinetic Theory

• An explanation for how the particles in gases behave. 

• 1) All matter is composed of tiny particles (atoms, molecules, and ions)

• 2) These particles are in constant, random motion

• 3) The particles collide with each other and with the walls of any container in which they are held. 
  

• 4) The amount of energy that the particles lose from these collisions can be ignored.

Gaseous State

• Small molecules compared to the distance between the particles

• Particles are in constant, random motion

• Frequent collisions between molecules

• The higher the temperature, the more kinetic energy the particles have, which means the speeds of the particles increase as temperature increases. 

• A gas will expand to fill its container, which means it does not have definite shape or volume. 

Liquid State

• Liquids have more kinetic energy/speed than solids, but less than gases.

• Liquids will change shape depending on their container, but do not change in volume like gases. 

• Liquids are said to have "indefinite shape" and "definite volume" 

Solid State

• Particles have low kinetic energy, but are moving (vibrating) in place. 

• They are bound to the particles around them, which does not allow them to move freely.

• Particles are bound by intermolecular forces of attraction. 

Multiple Choice

How particles behave in various states of matter, including how they move and how they are arranged, is described by:

• The Kinetic Theory of Matter

• Matter and Thermal Energy

• Melting Point

• Heat of Fusion

Multiple Choice

All matter is composed of

• particles

• collisions

• motion

• gases

Multiple Choice

The Substance in Example A is most likely in which state of matter?

• solid

• gas

• liquid

• plasma

Multiple Choice

The substance in Example C is most likely in which state of matter?

• solid

• liquid

• gas

• plasma

Multiple Choice

The substance in Example B is most likely in which state of matter?

• solid

• liquid

• gas

• plasma

Thermal Energy

• Thermal Energy - the total energy (kinetic and potential) of a material's particles.

• There is energy from the motion of the particles (Kinetic) as well as from inside the atoms known as binding energy (Potential) 

• Inrease in Temperature = Increase in the Average Kinetic Energy of the Particles 

Temperature

• A term used to explain how hot or cold something is. 

• Temperature is another way of represeting the average kinetic energy of the particles that make up a substance. 

• Molecules of water at 0°C have less kinetic energy than molecules of water at 100°C. 

Changes of State

• What happens to an ice cube when placed in a glass at room temperature?

• Over time, the ice absorbs the heat from its environment and begins to melt. 

• By changing from a solid to a liquid, this is known as a change of state. 

• A change of state occurs any time matter goes from one state to another (solid, liquid, gas, or plasma) 

Multiple Choice

When a solid can change state from a solid directly to a gas, without becoming a liquid first, that process is known as:

• sublimation

• condensation

• heat of vaporization

• evaporation

Melting

• As ice sits in a glass on the countertop, absorbing thermal energy, it begins to melt. 

• The temperature at which a solid becomes a liquid is known as its melting point. 

• The energy required to change a substance from solid to liquid at its melting point is known as heat of fusion. 

• The graph to the right shows the relationship between time and temperature for water. Why do you think the melting (red) and boiling (green) periods are flat? 
  

Open Ended

What is your hypothesis for the flat segments noted on the graphs? *Reminder: you have 3 minutes to form your response, so please take your time in crafting it. Science teachers care about grammar, too.

Multiple Choice

A student is conducting an experiment and is observing the temperature of a container filled with ice. The student begins recording the temperature immediately after the container is removed from the freezer. He records the temperature as soon as he notices the ice melting. This temperature is known as the water's:

• melting point

• heat of fusion

• mass

• average kinetic energy

Multiple Choice

The amount of energy required to change a substance from solid to liquid at its melting point is referred to as:

• the heat of fusion

• the melting point

• the melting fusion

• the fusion point

Vaporization

• Figure: As the temperature increases, the particles that make up the substance in its liquid state move faster. When the energy creates enough pressure to break the air pressure above the liquid, the water boils. 

• The steam that rises off of boiling water is the water changing from the liquid state to the gaseous state, this is known as vaporization. 

• Vaporization occurs in two ways: evaporation and boiling. 

Boiling

• Boiling is one of the ways vaporization occurs. 

• When the liquid reaches a temperature at which bubbles begin to form, that means that water vapor is forming inside of the water and is rising to the top to escape.

• The temperature at which this pressure difference occurs is known as the boiling point. 

• The heat/energy required to achieve this process is known as the heat of vaporization. 

Condensation

• The opposite process to Vaporization (A gas becomes a liquid) is known as condensation. 

• As the kinetic energy of the molecules decreases, the vapor turns to liquid and forms water droplets on the surfaces of nearby objects. 

Open Ended

Can you think of two examples of condensation that you have experienced?

Multiple Choice

As the temperature increases in a liquid, there is a difference in pressure between the surface of the liquid and the external pressure pushing down on it. When these two values are equal to each other, this is referred to as the liquid's:

• boiling point

• freezing point

• heat of fusion

• heat of vaporization

Multiple Choice

Since energy is conserved, there is no way to heat a substance without adding energy to the system. This usually comes in the form of a heating plate or flame. The energy required for a liquid to become a gas at its boiling point is referred to as the:

• heat of vaporization

• boiling point

• sublimation

• heat of fusion

Multiple Choice

The state of matter, beyond the gaseous state, in which matter has enough energy to overcome the attractive forces between its particles and the attractive forces within its atoms, this is referred to as

• plasma

• thermal expansion

• heat of fusion

• thermodynamics

Thermal Expansion

• Remember that particles move faster as the temperature increases. This means that as the temperature increases, the volume tends to increase as well. 

• An increase in the size or volume of a substance when the temperature is increased is also known as Thermal Expansion. 

• Thermal expansion is the reason that hot air balloons rise, muffins expand in the oven, and the liquid in thermometers to rise and fall with changing temperature. 

Multiple Choice

Thermometers were originally filled with liquid mercury, which was known to increase in volume as its temperature increased. When the thermometer was placed into a warmer environment, the liquid would expand and a reading would be taken from the labels along the thermometer. This is an example of:

• thermal expansion

• condensation

• evaporation

• sublimation