Chapter 10- Liquids and Solids Bell Ringer: List and describe the 3 states of matter in molecular terms.
Studying Solids, Liquids and Gases • The study of solids, liquids, and gases require an understanding of: • The kinetic molecular theory • The arrangement of atoms within a molecule. • The intermolecular forces of attraction between particles.
Arrangement of Atoms Within Molecules • Important Factors to Consider: • Electronegativity differences • Molecular Symmetry
Intermolecular Forces- Dipole-Dipole Attraction • When the positive end of one polar molecule is attracted to the negative end of another polar molecule.
Intermolecular Forces- Hydrogen Bonding • When the positive hydrogen side of one polar molecule is attracted to the negative end of another molecule.
Intermolecular Forces- London Dispersion • Instantaneous Dipoles that are created by constantly moving electrons.
Three States of MatterShape • Gases have no shape because of little attractive forces and independent movement. Liquids take the shape of their container but do not expand readily because of attractive forces. Solid molecules have definite shape and are held in fixed position.
Section 4 Changes of State States of MatterDensity • Density is mass per unit volume and indicates the closeness of particles in a sample of matter. • Gas Liquid Solid Low High High
Three States of MatterParticle Energy • Differences in attractive forces slow down particle movement. • Gases- high kinetic energy because of low attraction between particles. • Liquids- moderate kinetic energy and attraction • Solids- low kinetic energy and high attractive forces.
EQ: What does it mean for something to have heat, or be hot? Temperature is related to the average kinetic energy of the particles in a substance. KE = mv2 2
2. SI unit for temp. is the Kelvin a. K = C + 273 (10C = 283K) b. C = K – 273 (10K = -263C) 3. Thermal Energy – the total of all the kinetic and potential energy of all the particles in a substance.
Physical Standard for Temperature “Kelvin” Triple Point of Water The temperature and pressure at which water, water vapor, and ice can coexist in equilibrium. Temperature = 0.01C Pressure = 4.58 mm Hg
Absolute Zero & the Kelvin Scale The Kelvin scale is setup so that its zero point is the coldest possible temperature--absolute zero, at which point a substance would have zero internal energy. This is -273.15 °C, or -459.69 °F. Absolute zero can never be reached, but there is no limit to how close we can get to it. Scientists have cooled substances to within 10-5 kelvins of absolute zero. How do we know how cold absolute zero is, if nothing has ever been at that temperature? The answer is by graphing Pressure vs. Temperature for a variety of gases and extrapolating. P gas A A gas exerts no pressure when at absolute zero. gas B gas C T (°C) 0°C -273.15°C
4. Thermal energy relationships a. As temperature increases, so does thermal energy (because the kinetic energy of the particles increased). b. Even if the temperature doesn’t change, the thermal energy in a more massive substance is higher (because it is a total measure of energy).
Fahrenheit Formula • On the Fahrenheit scale, there are 180°F between the freezing and boiling points and on the Celsius scale, there are 100°C. 180°F = 9°F = 1.8°F 100°C 5°C 1°C • In the formula for the Fahrenheit temperature, adding 32 adjusts the zero point of water from 0°C to 32°F. TF = 9/5 TC + 32 or TF = 1.8 TC + 32
Celsius Formula • TC is obtained by rearranging the equation for TF. TF = 1.8TC + 32 • Subtract 32 from both sides. TF - 32 = 1.8TC ( +32 - 32) TF - 32 = 1.8TC • Divide by 1.8 = °F - 32 = 1.8 TC 1.8 1.8 TF - 32 = TC 1.8
Cup gets cooler while hand gets warmer 5. Heat a. The flow of thermal energy from one object to another. b. Heat always flows from warmer to cooler objects. Ice gets warmer while hand gets cooler
Thermal Equilibrium Two bodies are said to be at thermal equilibrium if they are at the same temperature. This means there is no net exchange of thermal energy between the two bodies. The top pair of objects are in contact, but since they are at different temps, they are not in thermal equilibrium, and energy is flowing from the hot side to the cold side. hot cold heat 26°C 26°C No net heat flow The two purple objects are at the same temp and, therefore are in thermal equilibrium. There is no net flow of heat energy here.
Three States of MatterCompressibility • Compressibility- the ability to move particles closer together. • Gases- Highly compressible • Liquids- Slightly compressible • Solids- Non-compressible
State of MatterAttractive Forces Between Particles • Kinetic energy between solids and liquids is low allowing for dipole-dipole attraction, London dispersion or a crystalline lattice to occur. Attractive forces among gases are almost non-existent.
Three States of MatterDiffusion • Diffusion- the spontaneous mixing of the particles of two substances caused by their random motion. • Gases Liquids Solids Quick Slow None
States of MatterFluidity A fluid is a substance that’s atoms or molecules are free to move past each other and therefore can take the shape of the container. Gases Liquids Solids Fluid Fluid Not Fluid
Three States of MatterOrderliness of Particles • Gases Liquids Solids Random Some Order Crystalline Lattice
Liquid TermsCondensation • Term that refers to a gas changing to a liquid.
Liquid TermsEvaporation • Term that refers to the changing of a liquid into a gas.
Liquid TermsMelting/Freezing • Melting- the change of a solid into a liquid • Freezing- the change of a liquid to a solid
Liquid TermsViscosity Resistance to flow (molecules with large intermolecular forces).
Liquid TermsVolatile VOLATILE LIQUID • Liquids that evaporate readily and have very weak forces of attraction between particles.
Characteristics of LiquidsSurface Tension • The force that tends to pull adjacent parts of a liquid’s surface together thereby decreasing surface area to smallest possible size. It causes liquid droplets to take a spherical shape.
Characteristics of LiquidsCapillary Action • The attraction of the surface of a liquid to the surface of a solid.
Bell Ringer: • What is the term for the physical state change for each of the following Solid to a gas- Liquid to a gas- Gas to a solid- Gas to a liquid- Liquid to a solid- Sublimation Vaporization Condensation Deposition Melting
Solid TermsHygroscopic/Deliquescent • Hygroscopic- a substance that will capture water molecules from the air and hold them. • Deliquescent- a substance that is so hygroscopic that they take up enough water molecules from the air to dissolve and form a liquid.
Solid TermsHydrated Ions HYDRATED IONS • Ions that are chemically bonded to the water molecule.
Solid TermsAnhydrous Compound ANHYDROUS COMPOUND • A compound in which the water of hydration has been removed.
Solid TermsSublimation • Sublimation • The change of state from a solid directly to a gas.
Solid TermsDeposition • The change of state from a gas directly to a solid. The formation of frost is a popular example.
Types of SolidsAmorphous Solids AMORPHOUS SOLID • One in which the particle arrangement is random. • Examples: glass, plastic
Types of SolidsCrystalline Solids • Consists of crystals with an orderly geometric repeating pattern. They have a highly regular arrangement of their components [table salt (NaCl), pyrite (FeS2)].
Molecular CrystalsElectrons are Shared • Ammonium persulfate crystals are used as an alternative to traditional ferric chloride solutions for copper etching.
Covalent Network- DiamondEach atom is covalently bonded to the nearest atoms