“Matter in Motion” Chapter 2.1 and Chapter 3

“Properties of Matter” Matter is anything that has mass and occupies space.

Ch. 3 Section 1 – “Matter and Energy” The kinetic theory of matter states: Matter is made of atoms and molecules. These particles are always in motion, and the higher the temperature of a substance the faster the particles move. More massive particles move slower than less massive particles.

Ch. 3 Section 1 – “Matter and Energy” 3 main states of matter: Solid Liquid Gas

Ch. 3 Section 1 – “Matter and Energy” Solids: Particle Motion: Slow moving (hard to change position). Shape: Definite Volume: Definite

Ch. 3 Section 1 – “Matter and Energy” Liquids: Motion: Faster than solids Shape: Changing Volume: Definite

Ch. 3 Section 1 – “Matter and Energy” Gases: Motion: Faster than liquids Shape: Changing Volume: Changing

Ch. 3 Section 1 – “Matter and Energy” Plasmas are a 4th state of matter. They consist of free-moving ions and electrons. Properties: Same as gas, but can also conduct electricity. Found naturally in stars, lightning, fire, and in the aurora borealis. Found artificially in fluorescent light.

Ch. 3 Section 1 – “Matter and Energy”

Ch. 3 Section 1 – “Matter and Energy” Energy is the ability to change or move matter (to do work). The energy of motion is called kinetic energy. Because they are in motion, all particles have kinetic energy.

Ch. 3 Section 1 – “Matter and Energy” Temperature is the measure of the average kinetic energy with in an object. As temperature rises, so does the speed of the particles.

Ch. 3 Section 2 – “Change of State” Energy must be added or taken away from a substance to change its state of matter. The identity of a substance does not change during a change of state, but the energy of a substance does change.

Ch. 3 Section 2 – “Change of State” Solids change to liquids by melting. The melting point is the temperature at which a substance changes from solid to liquid (0o C for water).

Ch. 3 Section 2 – “Change of State” Evaporation is the change of a substance from a liquid to a gas. The boiling point is the temperature at which a substance changes from a liquid to a gas (100o C for water).

Ch. 3 Section 2 – “Change of State” During sublimation, solids change directly into gases (ex. carbon dioxide).

Ch. 3 Section 2 – “Change of State” Melting, evaporation, and sublimation all require a gain of energy.

Ch. 3 Section 2 – “Change of State” Condensation is a change of state from a gas to a liquid. The condensation point is the temperature at which a gas becomes a liquid (100o C for water).

Ch. 3 Section 2 – “Change of State”

Ch. 3 Section 2 – “Change of State” Freezing is the change of state from a liquid to a solid. The freezing point is the temperature at which a liquid becomes a solid (0o C for water).

Ch. 3 Section 2 – “Change of State” Both condensation and freezing require a loss of energy!

Ch. 3 Section 2 – “Change of State” Mass remains constant during a change in phase because of the law of conservation of mass. The laws says that mass cannot be created or destroyed. 100 lbs. water makes 100 lbs. of steam

Ch. 3 Section 2 – “Change of State” Energy remains constant during a change in phase because of the law of conservation of energy. The laws says that energy cannot be created or destroyed.

Ch. 3 Section 2 – “Change of State” Temperature is constant during changes of state.

Phase Change Diagrams Many phase change diagrams show the change of state in relation to pressure and temperature. The normal pressure at sea level is 1 atm.

Phase Change Diagrams The melting point can be found by following the pressure line at which a substance is at until it crosses the solid/liquid line. The vaporization point can be found by following the pressure line until it crosses the liquid/vapor line.

Phase Change Diagrams The Triple point is the condition of temperature and pressure in at which all three phases exist together at equilibrium. For water, this is 0.0099 °C and 0.006 atmospheres.

Phase Change Diagrams The Critical Temperature, Tc is the temperature beyond which the solid and liquid phases of the substance cannot exist. Put another way, above the critical temperature, the substance can only be found as a gas. For water, this temperature is 373.99 °C.

Phase Change Diagrams The Critical Pressure, Pc is the pressure above which the substance cannot exist as a gas. For water, this pressure is 217.75 atmospheres. The Critical Point is the point defined by the critical temperature and the critical pressure.

Phase Change Diagrams The slope of the line between the solid and liquid phase provides important information about the substance: a) If the slope is negative (as it is for water), then the substance is more dense as a liquid than it is as a solid. b) If the slope is positive (as it is for most substances), then the substance is more dense as a solid than it is as a liquid.

Ch. 3 Section 3 – “Fluids” Fluids are classified as liquids and gases.

Ch. 3 Section 3 – “Fluids” Fluids move at different rates depending on their viscosity. Viscosity is the resistance of a gas or liquid to flow. Honey has a higher viscosity than water

Ch. 3 Section 3 – “Fluids” Fluids exert pressure evenly in all directions. Pressure is the amount of force exerted on a given area of surface.

Ch. 3 Section 3 – “Fluids” Fluids pressure decreases as speed increases. This is Bernoulli’s principle.

Ch. 3 Section 3 – “Fluids” Buoyant force is the upward force that keeps an object immersed in or floating on a fluid. Archimedes principle says that the buoyant force of an object in a fluid is an upward force equal to the weight of the fluid that the object displaces.

Ch. 3 Section 3 – “Fluids” Sink or float? Density determines whether an object will sink or float. If an object is more dense than the liquid it is in, then it will sink. Distributing the mass of something over a larger area will make less dense it more buoyant.

Ch. 3 Section 3 – “Fluids”

Ch. 3 Section 4 – “Behavior of Gases” Boyle’s Law: For a fixed amount of gas at a constant temperature, the volume of a gas increases as the gas’ pressure decrease. Likewise, the volume of a gas decreases as the gas’ pressure increases.

Ch. 3 Section 4 – “Behavior of Gases” Gay Lussac’s Law: The pressure of a gas increases as the temperature increases, if the volume of the gas does not change. The pressure decreases as the temperature decreases.

Ch. 3 Section 4 – “Behavior of Gases” Charles’ Law: For a fixed amount of gas at a constant pressure, the volume of the gas increases as the gas’ temperature increases. Likewise, the volume of the gas decreases as the gas’ temperature decrease.

PRACTICE: Temperature INCREASES, Volume _________. Temperature DECREASES, Volume ____________. Pressure INCREASES, Volume ___________. Pressure DECREASES, Volume ____________. Temperature INCREASES, Pressure ___________. Temperature DECREASES, Pressure ______________. #1 & 2 = _____________________ Law #3 & 4 = _____________________ Law #5 & 6 = _____________________ Law

Ch. 3 Section 4 – “Behavior of Gases” Gas Laws Animation

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Gay-Lusaac’s Law Demonstration: Boyle’s and Charles’ Law Demonstrations