States of Matter

Phase Changes

• Turn to page 84 in your textbook.

• Read section 3.3 pages 84-91

• Answer the all the questions on p. 91 Section Assessment

States of Matter1. Solid

2. Liquid

3. Gas

4. Plasma

Solid Liquid Gas

Packing/spacing of particles

Movement of particles

Can it flow?

Take shape of container?

Fill volume of container?

Compressible?

What is volume?• the amount of 3-dimensional space

occupied by an object

Characteristics of Solids

• Definite shape• Definite volume• Particles packed together tightly• Expands slightly when heated

Characteristics of Liquids

• Definite volume• Takes shape of its

container• Particles close, but not

rigidly packed• Expands when heated

Characteristics of Gases

• Indefinite shape – takes shape of its container

• Indefinite volume – takes volume of its container

• Particles are far apart• Is easily compressed

Hot Air Balloons

http://videos.howstuffworks.com/discovery/http://videos.howstuffworks.com/discovery/36118-massive-engines-how-hot-air-36118-massive-engines-how-hot-air-balloons-work-video.htmballoons-work-video.htm

Gas or Vapor??

Gas

Vapor

exists in the gaseous state at room temperature.

Oxygen, Hydrogen, Nitrogen, Carbon dioxide

the gaseous state of a substance that generally exists as a liquid or solid at room temperature.Water vapor, Acetone, Nail polish remover, Perfume

Plasma

• exists only at extremely high temperature• an ionized gas• electrons have been stripped away from atoms• Plasma ball demonstration

Kinetic Theory

• All particles of matter are in constant motion:– Particles of a solid vibrate in a fixed location– Particles of liquid can slide past one another.

Constantly held close to one another.– Particles of a gas are mostly “free”.

Solid Liquid Gas

Packing/spacing of particles

VERY tight packed

tight packed VERY far apart

Movement of particles

Vibrate in place Flow past one another

Constantly in motion

Can it flow? NO Yes Yes

Take shape of container?

NO Yes Yes

Fill volume of container?

NO NO (think about a small amount of liquid vs. a large container)

Yes

Compressible? No “virtually incompressible”

Yes

Volume of water demo

• 3 different sized flasks…do they contain the same amounts of water?

ReviewStates of Matter and Density

1. What are two properties of all liquids?2. What are two properties of all gases?3. What are two properties of all solids?4. If salt takes the shape of the container it is poured into, why is it still considered a solid?5. Why is salt water considered a mixture and not a compound?6. Define compound and give an example of one.7. How are compounds and mixtures alike?8. A liquid was found to have a mass of 22.5 g and a volume of 25 ml. What is the liquid's density?

9. What is the mass of a gold ring whose volume is 5 cm3? Gold has a density of 19.3 g/cm3.

States of Matter and Density1. What are two properties of all liquids?2. What are two properties of all gases?3. What are two properties of all solids?4. If salt takes the shape of the container it is poured into, why is it still considered a solid?5. Why is salt water considered a mixture and not a compound?6. Define compound and give an example of one.7. How are compounds and mixtures alike?8. A liquid was found to have a mass of 22.5 g and a volume of 25 ml. What is the liquid's density? .9 g/ml9. What is the mass of a gold ring whose volume is 5 cm3? Gold has a density of 19.3 g/cm3. 96.5 g

Structure of Matter Animation

• Click on structure of matter link on left side of page

What’s the Matter Mini Lab• All matter that we see or touch, and even ones that we can’t see or touch are in one of

• three states: They are solids, liquids, or gases. In this activity you will be studying the

• different states of matter. When scientists think or talk about matter they mean every

• substance in the universe from the largest planet to the tiniest speck of dust. But what is

• matter? In the following experiment you will observe a form of liquid matter to try to

• determine what matter is made of.

•  

• Materials

• · 2 10 mL graduated cylinders

• · eyedropper

• · water

• · alcohol

•  

• Procedure

• 1. Put 10.0 mL of water in a 50 mL graduated cylinder. Be careful! Your measurements need to be as precise as possible!!!! Use an eyedropper or pipet if needed!

• 2. Put 10.0 mL of alcohol into the 10 mL graduated cylinder.

• 3. Carefully pour the alcohol into the water.

• 4. Observe what happened in the graduated cylinder and answer the questions below.

•  

• Questions:

• 1. What happens when you mix the two liquids together?

• 2. After the liquids were mixed together, do they take up the same space as they did

• before? How do you know?

•  

What’s the Matter mini-lab explained

• Sometimes the volume of the mixture is less than, some times the sum of, and other times greater than the volume of the components. In the case of ethanol (alcohol) and water the volume of some concentrations is less than the sum of the components. Liquid water has a somewhat "open" structure that is broken up by the addition of ethanol so the mixture "collapses". In general there is no good way of predicting volumes of mixing of either liquids or of liquids and solids.

States of Matter – Lesson 2

• Phase Changes and Heating Curves

Phase Changes – see p.85 in text!

• a.k.a. changes of state

• melting/freezing

• vaporization/ condensation

• sublimation/ deposition

Thermal Energy & States of Thermal Energy & States of MatterMatter

• Solid – atoms are in a fixed position, they only vibrate back Solid – atoms are in a fixed position, they only vibrate back and forth. Solids have both a definite shape and definite and forth. Solids have both a definite shape and definite volume.volume.

• Liquid – atoms are free to slide over and upon each other. Liquid – atoms are free to slide over and upon each other. Liquids have a definite volume but not a definite shape.Liquids have a definite volume but not a definite shape.

• Gas – atoms are free to move independently of other atoms Gas – atoms are free to move independently of other atoms of the substance. Gases have neither a definite shape or of the substance. Gases have neither a definite shape or volume.volume.

Phase Changes

• Temperature does not change during a phase change

Graphs showing freezing and melting points

• http://apps.caes.uga.edu/sbof/main/lessonPlan/FreezingMeltingWater.pdf

• In both graphs, there is a region (bounded by the red bars) that represents the phase change of the water. In these intervals, there is no kinetic energy. However, potential energy is either increasing (as in the case during melting) or decreasing (as in the case during freezing) in these intervals.

Phase Changes – see p.85 in text!

• TEMPERATURE does not change during a phase change.

• ENERGY is being absorbed or released during a phase change.

• Red arrows are endothermic!

• Blue arrows are exothermic!

Energy Changes

• A process that releases energy is called an exothermic process.

• A process that absorbs energy is called an endothermic process.

Melting Freezing

• solid → liquid

• particles become more disordered

• particles ABSORB energy to increase their disorder

• endothermic

• liquid → solid

• particles become more orderly

• particles RELEASE energy to become more ordered

• exothermic

Vaporization Condensation

• liquid → gas

• particles become more disordered

• particles ABSORB energy to increase their disorder

• boiling, evaporation• endothermic

• gas → liquid

• particles become more orderly

• particles RELEASE energy to become more ordered

• exothermic

Sublimation Deposition

• solid → gas• NO change to liquid in

between!• particles become more

disordered• particles ABSORB energy

to increase their disorder

• dry ice (solid CO2), iodine

• endothermic

• gas → solid

• particles become more orderly

• particles RELEASE energy to become more ordered

• frost on a window• exothermic

1. What are the characteristics of a solid?

2. What is plasma?

3. Give an example of freezing.

4. Give an example of condensation.

• Temperature does not change during a phase change.

• Energy is being absorbed or released during a phase change.

• Exothermic – energy (heat) is released

• Endothermic – energy is absorbed

Heating Curve

• Graph showing effect on temperature as heat is added to a substance

• Shows the physical changes that occur as heat is added (changes in temperature AND changes of state)

Time

Tem

pera

ture

Time

Tem

pera

ture

Time

Tem

pera

ture

solid

liquid

gas

Time

Tem

pera

ture

solid

liquid

gas

melting

vaporization

Time

Tem

pera

ture

0°C

100°C

solid

liquid

gas

melting

vaporization

These numbers are for water only

Time

Tem

pera

ture

solid

liquid

gas

melting

vaporization

Review

• Explain the differences between:– melting/freezing– vaporization/ condensation– sublimation/ deposition

• Can you explain the Heating Curve Graph on the next slide?

Heating Curve Graph

Heating Curve Graph Activity

• Please do the Heating Curve Graph Activity

States of Matter – Lesson 3

• Gas Laws

Gas Laws!!!

• Solid Liquid Gas• Orderly not very not at all• Forces strong not very no forces

• For phase change in this direction, particles must absorb energy (endothermic reactions)

• For phase change in this direction, particles must release energy (exothermic reactions)

Kinetic Theory of Gases

• Gas particles are in constant, random motion.

• Particles do not interact except when they collide by chance.

• No forces of attraction exist between particles.

Gas Pressure

• a result of the collisions between gas particles and the walls of the container

• measured in pascals (usually kilopascals, kPa)

Pressure

• A force distributed over an area.

Gas Pressure

• Affected by several factors– Temperature

– Volume

– Number of Particles

P T V

Make a card and put your penOr pencil on the factor that is heldConstant. As you move the card Up or down, it will let you know whatHappens to each factor!!

Example: If Temp is held constant, whatHappens to volume when pressure increases? As you hold your pen on the T and move the P up, You will see that V goes down…so, volume decreases!!!!

Pressure and Temperature(at constant volume)

• As temperature increases, pressure increases.

• As temp increases, kinetic energy of particles increases. Particles collide more often with walls of container and with greater force.

Pressure and Volume(at constant temperature)

• As pressure increases, volume decreases.

As pressure decreases, volume increases.

• As volume increases, pressure decreases.

As volume decreases, pressure increases.

Pressure and Volume(at constant temperature)

WHY does pressure decrease when volume increases?

When the volume of the container increases, there is a larger inside surface of the container. The same number of particles (moving the same as before) will be hitting the inside surface just as often as they did before, except now those hits are over a larger area.

Pressure and Number of Particles(at constant temperature and volume)

• Easy!!

• More particles = higher pressure

• More particles results in more collisions with the walls of the container.

Volume and Temperature(at constant pressure)

• As temperature increases, volume increases.

• As temp increases, kinetic energy of particles increases. Particles collide more often with walls of container and with greater force. In a flexible container, the walls will expand as a result.

Boyle’s Law

P V P V1 1 2 2

the volume of a gas is inversely proportional to its pressure if the temperature and number of particles are constant.

Boyle’s Law

Boyle’s Law Animation

Charles’s Law

V

T

V

T1

1

2

2

– the volume of a gas is directly proportional to its temperature in kelvins if the pressure and the number of particles of the gas are constant.

The Combined Gas Law

P1 V1 = P2 V2

T1 T2

Gas Law Animation

• http://www.mhhe.com/physsci/chemistry/essentialchemistry/flash/gasesv6.swf

1.6 L

100 kPa

P1V1 = P2V2

T1 T2

Pressure Demonstrations

• Boiling Water at Room Temp

• Marshmallow/Marshmallow Man

• Inflating Balloon

• Balloon Vaccum?

Pressure• A gas exerts pressure on all sides of the container which holds the gas. The

amount of pressure is related to the energy of the gas and the amount of gas. The higher the energy, the more pressure is exerted, and the more gas is contained, the more pressure is exerted.

Gases expand to fill the boundaries of their containers. Once a gas has filled the container, it keeps pressing outwards, continuously trying to expand. This expansion creates a pressure on the sides of the container. The pressure is exerted by the molecules of the gas colliding with the sides of the container. The more energy a gas has, the more energy its molecules will have, and the more pressure will therefore be exerted. If there is more gas inside a given container, there will be a higher number of average collisions with the sides of the container, and more pressure will therefore be exerted.

A container may be of any size and shape. A common container of air is a balloon. Another container of gas is the Earth's atmosphere: the gas inside the Earth's atmosphere is constantly pushing against the sides of its container (including you!). Due to the gas contained in the atmosphere, we are all constantly under a pressure of about fifteen pounds per square inch.

Boiling Water at Room Temperature

• Atoms or molecules that make up a solid or a liquid are very close together. If you lower the pressure (in other words, make a vacuum) this means that there will be very few gas atoms or molecules near the surface of the solid (or liquid). This, in turn, makes it very unlikely for any molecule that leaves the surface to be replaced. So as you make the pressure lower, the 'stuff' you're dealing with will have a harder time coming together to make a solid (or a liquid).

Actually, below a certain pressure, you can't get a liquid at all. Below that pressure, if you cool a gas down, it will do something called 'crystal lattice formation' and go straight from a gas to a solid. (The opposite of this, going from a solid to a gas, is called 'sublimation.')

The boiling point for a liquid will also drop at lower pressures. In fact, you can actually get a liquid to boil at room temperature if you have a vacuum.

• High altitude cooking – see next slide!!• http://www.ext.colostate.edu/pubs/foodnut/p41.html•

High Altitude Cooking• At altitudes above 3,000 feet...

• At altitudes above 3,000 feet, preparation of food may require changes in time, temperature or recipe. The reason, lower atmospheric pressure due to a thinner blanket of air above. At sea level, atmospheric pressure is 14.7 pounds per square inch (psi), at 5,000 feet it’s 12.3 psi, and at 10,000 feet only 10.2 psi - a decrease of about 1/2 pound per 1,000 feet. This decreased pressure affects food preparation in two ways:

• Water and other liquids evaporate faster and boil at lower temperatures.

• Leavening gases in breads and cakes expand more quickly.

• The temperature at which water boils declines as elevation rises (Table 1). Because of this, foods prepared by boiling or simmering cook at a lower temperature at high altitude than at sea level, and thus, require a longer cooking time. Meats cooked by simmering or braising may require one-fourth more time at 5,000 feet than at sea level. Oven temperatures, however, are not affected by altitude, so sea-level instructions work for oven-roasted meats. Hard-cooked eggs will also take longer to cook. A “three-minute” egg may take five minutes to cook at 5,000 feet. High altitude areas are also prone to low humidity, which causes the moisture in foods to evaporate more quickly during cooking. Covering foods during cooking will help hold in moisture.

Marshmallow Man• The chemical structure of a marshmallow is such that there are many pockets of air trapped by sugar

molecules. These pockets of air are constantly applying pressure to the sugar molecules in the amount of approximately 15 pounds per square inch.

A gas exerts pressure on all sides of the container which holds the gas. The amount of pressure is related to the energy of the gas and the amount of gas. The higher the energy, the more pressure is exerted, and the more gas is contained, the more pressure is exerted.

On an average day, the air pressure pressing on all things at the surface of the Earth is approximately 15 pounds per square inch.

Step 1: The marshmallow man is under normal circumstances. The air pressure inside the marshmallows exactly equals the air pressure around the marshmallows.

Step 2: The vacuum pump is turned on and the air inside the bell jar is slowly sucked out. This causes a decrease in air pressure around the marshmallows. Since the air pressure inside the marshmallows has not changed, there is now a difference in pressure. The force on the sugar molecules from the air inside is now greater than the force on the sugar molecules from the outside. The marshmallows expand and air eventually leaves the marshmallows.

Step 3: When the air was pumped out of the bell jar in the previous step, the force inside the marshmallows caused the marshmallows to expand. The force became so great, however, that much of the air inside the marshmallows escaped. When the air was allowed to flow back into the container, the air inside the marshmallows had decreased, so the marshmallows deflated.

Frostbite Theater

• Koosh Ball in Liquid Nitrogen