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Explore the properties of solids, liquids, and gases and learn about phase changes in this chapter. Understand how particles in different states of matter behave and the effects of energy on these states. Discover the concept of vaporization, condensation, freezing, and melting. Gain insights into the different behaviors of solids, liquids, and gases and how they change from one state to another.
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Chapter 3 States of Matter
States of Matter Imagine that you have a baseball and a small packet of ketchup. 1. If you squeeze the ketchup packet, how would it change? 2. If you squeeze the baseball, how would it change? 3. What would these results tell you about the properties of solids and liquids?
The three states . . . a. definite shape b. definite volume c. variable shape d. variable volume
How would you describe the states of matter? Materials are classified based on whether their shapes and volumes are definite or variable. Shape and volume are clues to how particles in a substance are arranged
Solids Definite shape Definite volume Some type of orderly arrangement at the atomic level
Liquids Always has the same shape as its container Can be poured from one container to another Atoms close together but arrangement is more random then a solid
Gases Takes the shape of its container Molecules are arranged randomly & spread out Gas molecules can be compressed because the space between them is great How many helium balloons do you think one helium tank can fill?
Are there other states of matter? • On Earth – almost always, only three states of matter • In the Universe – 99% of matter exists at extremely high temperatures in the form of plasma
Kinetic Theory • All particles of matter are in constant motion • The faster something moves, the more KE it has • Also applies to ALL atoms within a substance
Motion in Gases • Particles are never at rest • Some are moving faster then others He atoms travel in a straight line until they collide with another He atom or the side of the container When they collide, one may lose KE, one may gain KE Total energy of atoms remains the same
Kinetic Theory of Gases • Particles in a gas are in constant random motion • The motion of one particle is unaffected by that of another unless the particles collide • Forces of attraction among gas particles can be ignored under normal conditions
The Behavior of Liquids • Particles in constant motion, but slower than in a gas • Forces of attraction DO AFFECT the movement • Volume is constant because of these forces of attraction; they keep the particles together
The Behavior of Solids • Similar to people in a movie theater • Atoms vibrate, but don’t move places
Phase Changes Definition: Reversible physical change that occurs when a substance changes from one state of matter to another. 6 Types: Melting, freezing, vaporization, condensation, sublimation, deposition
Phase Change Diagram Sublimation: solid to gas Condensation: gas to liquid Deposition: gas to solid Melting: solid to liquid Vaporization: liquid to gas Freezing: liquid to solid
Temperature and Phase Changes • Temperature of a substance doesn’t change during a phase change.
Energy & Phase Changes • During a phase change, energy is transferred between a substance and its surroundings. • Energy is either absorbed or released • Types of reactions: endothermic and exothermic
Endothermic Reactions Endothermic reaction of barium hydroxide and an ammonium salt. When you mix the two solids; they react, and the products dissolve in water of hydration. The reaction flask becomes extremely cold. System absorbs energy from its surroundings
Exothermic Reactions Energy released to the environment
Melting & Freezing • Melting • Heat flows from air to ice • Ice gains energy, molecules speed up • When enough energy provided, all molecules can move and melting is complete • MP of water is zero degrees celsius • Freezing • Energy flows from substance to air • KE slows down • At FP, attractions between molecules increase • When molecules are arranged, freezing occurs
Vaporization & Condensation • Vaporization • Liquid to gas • Amount of energy required is heat of vaporization • Condensation • Gas to liquid
Evaporation • Liquid to gas below bp • Greater surface area = faster evaporation rate • At the surface, some molecules move fast enough to escape the liquid • Sealed container causes VP to rise