Ch. 2 “Matter”Ch. 2 “Matter”

2.1: “What Is Matter?”2.1: “What Is Matter?” 2.2: “Matter and Energy”2.2: “Matter and Energy” 2.3: “Properties of Matter”2.3: “Properties of Matter”

2.2: “Matter & Energy”2.2: “Matter & Energy”

Objectives:Objectives:1.1. Use the kinetic theory to describe the Use the kinetic theory to describe the

properties and structures of the different properties and structures of the different states of matter.states of matter.

2.2. Describe energy transfers involved in Describe energy transfers involved in changes of state.changes of state.

3.3. Describe the laws of conservation of Describe the laws of conservation of mass and conservation of energy, and mass and conservation of energy, and explain how they apply to changes of explain how they apply to changes of state.state.

Recall Method: Recall Method: Why can you smell cookies baking in a Why can you smell cookies baking in a bakery when you are far from the oven?bakery when you are far from the oven?

Reasons…Reasons…

11stst: Assume that particles (atoms & : Assume that particles (atoms & molecules) within substances can move.molecules) within substances can move.

22ndnd: Assume that the atoms & molecules : Assume that the atoms & molecules move faster as the temperature rises.move faster as the temperature rises.

33rdrd: Energy moves from the oven to the : Energy moves from the oven to the cookies, causing molecules in the cookie cookies, causing molecules in the cookie dough to move fast & become gases dough to move fast & become gases which spread out.which spread out.

Kinetic TheoryKinetic Theory All matter is made of atoms & molecules All matter is made of atoms & molecules

that act like tiny particles.that act like tiny particles. Tiny particles are in constant motion. Tiny particles are in constant motion.

Higher temp. faster the movement.Higher temp. faster the movement. At the same temperature, more massive At the same temperature, more massive

(heavier) particles move slower than less (heavier) particles move slower than less massive (lighter) particles.massive (lighter) particles.

Fluids

SolidsSolids:: Rigid structureRigid structure Fixed volume and shapeFixed volume and shape Strong attractions of particles = vibrateStrong attractions of particles = vibrateLiquidsLiquids:: Definite volumeDefinite volume No specific shapeNo specific shape Particles flow = easily slide Particles flow = easily slide ViscosityViscosity: The resistance of a fluid to flow.: The resistance of a fluid to flow.(The higher the attraction of the particles, the slower (The higher the attraction of the particles, the slower fluid will flow.)fluid will flow.)** both liquids and gases are fluids!!** both liquids and gases are fluids!!GasesGases:: Particles are far apart & move randomlyParticles are far apart & move randomly No fixed volume or shapeNo fixed volume or shape Gases can exert pressureGases can exert pressure

Why does a balloon with helium go Why does a balloon with helium go “flat” faster than a balloon filled with “flat” faster than a balloon filled with

air?air? The wall of the balloon has The wall of the balloon has

tiny holes through which tiny holes through which gas particles can escape. gas particles can escape. The helium particles are The helium particles are smaller & less massive than smaller & less massive than the nitrogen & oxygen the nitrogen & oxygen particles found in the air. particles found in the air. The smaller & less massive The smaller & less massive particles move faster, so particles move faster, so they get through the holes they get through the holes more quickly. more quickly.

What is the role of energy?What is the role of energy?

Demonstration (2 volunteers)Demonstration (2 volunteers)

1) Dip one index finger into the water. Dip 1) Dip one index finger into the water. Dip your other index finger into the oil. Wave your other index finger into the oil. Wave each finger in the air.each finger in the air.

2) Do your fingers feel cool?2) Do your fingers feel cool?

3) Which liquid evaporated faster?3) Which liquid evaporated faster?

4) Repeat experiment using water on one 4) Repeat experiment using water on one finger and rubbing alcohol on the other.finger and rubbing alcohol on the other.

What happened??What happened??

Which of the three liquids evaporated the Which of the three liquids evaporated the fastest? Slowest?fastest? Slowest?

Which liquid cools the skin the most? Least?Which liquid cools the skin the most? Least?

The molecules in each liquid absorb energy from The molecules in each liquid absorb energy from their surroundings (skin) increasing the speed of their surroundings (skin) increasing the speed of molecules. Alcohol requires the least energy to molecules. Alcohol requires the least energy to escape from liquid. Oil requires the most!!escape from liquid. Oil requires the most!!

Energy’s RoleEnergy’s Role

Energy: The ability to change or move Energy: The ability to change or move matter.matter.

The Changes of State for WaterThe Changes of State for Water

EvaporationEvaporation: The change of a substance : The change of a substance from a liquid to a gas = cooling processfrom a liquid to a gas = cooling process

CondensationCondensation: The change of a : The change of a substance from a gas to a liquid = heating substance from a gas to a liquid = heating process: (must have a surface for it to process: (must have a surface for it to condense on!!!)condense on!!!)

SublimationSublimation: The change of a substance : The change of a substance from a solid to a gas.from a solid to a gas.

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Changes of State for Water: Page 49 Fig. 2-14 pg. 49

ExamplesExamples

Evaporation = liquid to gasEvaporation = liquid to gas ex: sweatex: sweat

Condensation gas to liquidCondensation gas to liquid ex: cold can of pop sweatsex: cold can of pop sweats

Sublimation = solid to gasSublimation = solid to gas ex: Dry Ice: Directly from solid to gasex: Dry Ice: Directly from solid to gas

Graphic Organizer: Changes of Graphic Organizer: Changes of States Of WaterStates Of Water

Solid Liquid Gas

Sublimation

Melting Boiling or Evaporation

Freezing Condensation

Law of Conservation of MatterLaw of Conservation of MatterLaw of Conservation of EnergyLaw of Conservation of Energy

Mass cannot be created or destroyed Mass cannot be created or destroyed (Matter can change from one form to (Matter can change from one form to another but the total mass stays the another but the total mass stays the same.)same.)

Energy cannot be created or destroyed Energy cannot be created or destroyed (Energy can be changed from one form (Energy can be changed from one form into another but total amount stays the into another but total amount stays the same.)same.)

Were You Paying Attention?Were You Paying Attention?

DefineDefine energy energy State State the Law of Conservation of Energy the Law of Conservation of Energy

and the Law of Conservation of Mass.and the Law of Conservation of Mass. ListList two examples for each of the three two examples for each of the three

common states of matter.common states of matter. RankRank the following in order of increasing the following in order of increasing

strength of forces between molecules.strength of forces between molecules.a. Honey b. Marble c. Water a. Honey b. Marble c. Water

d. Nitrogen Gas e. Candle Waxd. Nitrogen Gas e. Candle Wax

Continued….Continued….

CompareCompare and contrast the shape and and contrast the shape and volume of solids, liquids, and gases.volume of solids, liquids, and gases.

PredictPredict which two of the following involve which two of the following involve the same energy transfer. Assume that the same energy transfer. Assume that the same substance and the same mass the same substance and the same mass is involved in all four processes:is involved in all four processes:

a. Melting b. Sublimation a. Melting b. Sublimation c. Evaporation d. Condensation c. Evaporation d. Condensation

ContinuedContinued

Describe the energy transfers that occur Describe the energy transfers that occur when ice melts and water vapor when ice melts and water vapor condenses to form liquid water.condenses to form liquid water.

Homework: Creative Thinking:Homework: Creative Thinking:

Describe a characteristic of gases, and Describe a characteristic of gases, and use the kinetic theory to explain how a dog use the kinetic theory to explain how a dog could find you by your scent.could find you by your scent.