States of Matter

Four states of matter Solid Liquid Gas Plasma

SOLIDS Definite Shape and Volume Particles are often arranged in repeating geometric patterns to form crystals Some are composed of particles with no particular order (amorphous solids)

Liquids Definite Volume Indefinite Shape Can’t normally be squeezed into a smaller space Indefinite Shape Flow and take shape of container

Gases No definite shape or volume Molecules can be squeezed together or spread out to fill the space available

Plasma Gas-like mixture of positively and negatively charged particles Only exists at very high temperatures MOST of the matter in the universe!! Around 99% Ex’s natural plasmas- lightning, fire artificial- fluorescent light

Which state of matter has a definite volume, but not a definite shape? Solid Liquid Gas Plasma 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Terms related to states of matter

Kinetic Theory of matter Question #1 on page 78 All matter is made of atoms and molecules that act like particles These particles are always in motion. The higher the temperature of the substance, the faster the particles move. At the same temp, more massive (heavier) particles move slower than less massive (lighter) particles

Kinetic Theory of matter In other words… All matter is made of tiny particles (atoms) in constant motion How MUCH they move depends on how much energy they have Increased temperature will… increase kinetic energy= more movement

Thermal expansion Almost all matter expands as it gets hotter and contracts when it cools. Temperature is a measure of the average kinetic energy of the particles in the object Theoretically, absolute 0, (0 degrees Kelvin) has no movement of particles Never achieved in a lab

Temperature is a measure of the _______ of the particles in an object Degrees Celsius Average Kinetic Energy Average Potential Energy 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Energy of PHase changes

Exothermic PHASE CHANGES ENERGY RELEASED Energy is RELEASED from the substance out to its surroundings Ex’s- each of these products have molecules with LESS energy than they did before the phase change Freezing (liquid water has more energy than ice) Condensation (gas to liquid) Deposition (gas to solid)

Endothermic PHASE CHANGES ENERGY REQUIRED Energy is ABSORBED by the substance from its surroundings Ex’s- each of these products have molecules with MORE energy than they did before the phase change Melting (ice has less energy than water) Evaporation (liquid gas) Sublimation (solid gas))

For each of the following… Name the process described and then determine if it is exothermic or endothermic

liquid to gas… Sublimation, Exothermic Condensation, Exothermic Evaporation, Endothermic Sublimation, Endothermic Condensation, Endothermic 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Gas to liquid… Sublimation, Exothermic Condensation, Exothermic Evaporation, Endothermic Sublimation, Endothermic Condensation, Endothermic 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Solid to gas… Sublimation, Exothermic Condensation, Exothermic Evaporation, Endothermic Sublimation, Endothermic Condensation, Endothermic 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Intermolecular forces The force between two molecules Holds them together weakly Stronger in a solid than liquid, etc.

Intermolecular Forces The attractions between molecules are not nearly as strong as the intramolecular attractions that hold compounds together.

Intermolecular Forces They are, however, strong enough to control physical properties such as boiling and melting points, vapor pressures, and viscosities.

Intermolecular Forces Affect Many Physical Properties The strength of the attractions between particles can greatly affect the properties of a substance or solution.

Viscosity Resistance of a liquid to flow is called viscosity. It is related to the ease with which molecules can move past each other. Viscosity increases with stronger intermolecular forces and decreases with higher temperature.

Surface Tension Surface tension results from the net inward force experienced by the molecules on the surface of a liquid.

Water is special Contains H bonds (which are not actually bonds, but strong Intermolecular forces) Gives water special properties like… Density of ice is special! Surface Tension!

Phase Changes

The States of Matter The state a substance is in at a particular temperature and pressure depends on two antagonistic entities: The kinetic energy of the particles The strength of the attractions between the particles

Phase changes cannot occur without breaking or forming the if forces

Energy Changes Associated with Changes of State The heat added to the system at the melting and boiling points goes into pulling the molecules farther apart from each other. The temperature of the substance does not rise during the phase change.

**In order to change state, these Intermolecular Forces must be broken or formed, and this requires adding or subtracting __________________Energy The energy put in to break bonds at a phase change is __________ ____ the energy released when the bonds are reformed to change back! Heat of Vaporization: Energy required to change a liquid at its boiling point to a gas is equal to the energy released from the particles when a gas is changed to a liquid! Heat of Fusion: Energy required to change a solid at its melting point to a liquid is equal to the energy released from the particles when a liquid is changed to a solid!

So what does this mean about melting and freezing point temperatures? They are EQUAL!

Special Info about the Heating and Cooling Curves of Water heating curve of water animation The total energy absorbed in the heating curve is equal to the total energy released in the cooling curve of water Melting/freezing pt: occur at same temperature Boiling/condensation pt: occur at same temperature

More Special info Temperature does not change during a phase change So, the graphs have 2 main plateau areas where phase changes are occurring

Cooling Curve of Water

Using everything we have learned… Explain what happens when a cold glass of water “sweats”

Condensation - gas to liquid Water particles in the air have more kinetic energy (heat) than the glass of water. As water particles get close to the glass, energy is transferred from the particles to the glass. This starts the following process… a. Particles lose kinetic energy, slow down, and come closer together. IF’s become strong enough to make particles merely rotate around each other. The energy they lose to turn into a liquid is the heat of vaporization. Substance is releasing energy to the surroundings (exothermic)

Using everything we have learned… Explain what happens when liquid water changes to ice.

Freezing - liquid to solid-. a. Particles lose kinetic energy and slow down. b. Substance releases energy to surroundings (exothermic) c. IF’s b/w particles become stronger than the particles’ motion, so the particles begin merely vibrating in place to form a solid. d. The amount of heat the particles must lose to turn into a solid is called the heat of fusion.

Is this a heating or cooling graph? Both of the above None of the above 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

There are two flat sections in the above graph. Why? IF are breaking IF are being created (forming) The phase change is increasing the temp None of the above 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

A cooling curve is 10 Exothermic and a chemical change Endothermic and a physical change endothermic and a chemical change Exothermic and a physical change 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Which of the following is sublimation? Solid to liquid Solid to gas Liquid to gas Gas to liquid 10 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Which type of matter has a definite shape and definite volume? 10 Which type of matter has a definite shape and definite volume? Gas Liquid Solid plasma 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Which type of matter has indefinite shape but definite volume and can take the shape of the container? Gas Liquid Solid plasma 10 0 of 28 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

Why are there 2 portions of the phase change curve in which the temperature is not increasing? (the water is not removed from the heat source during any portion of time)

10 Ice stage Water + ice stage Water stage Water vapor stage At which of the following stages in the experiment would the average molecular speed of the water molecules be greatest? Ice stage Water + ice stage Water stage Water vapor stage 10 0 of 28

Law of conservation of mass Law of conservation of motion What is the theory that says tiny particles are always in motion and the higher the temp. the faster the particles move? Thermal energy Kinetic theory Law of conservation of mass Law of conservation of motion 10 0 of 28