Chapter 13 States of Matter

States of Matter matter classified as one of these physical states solids, liquids and gases. 4th state of matter—plasma: does not occur naturally on Earth except in the form of lightning bolts.

States of Matter

States of Matter The physical state of a sub is a physical property of that sub. Other physical properties: m.p., b.p., heat conductivity, electricity conductivity, color, crystal shapes, hardness etc.

Solids A solid is a physical state matter that has definite shape and definite vol. e.g.Wood, Fe, paper, and sugar

Solids particles tightly and orderly packed. When heated, expands slightly fixed position (particles just vibrate) Definite shape Not conform to shape of container

Solid Particle Movement Examples

Liquids A liquid is a state of matter that flows (fluids) constant volume, and takes the shape of its container. e.g. liquids : H2O, blood, and Hg. Particles not rigidly held in place less closely packed than those in a solid: able to move past each other. move much faster than (s)

Liquids allows a (l) to flow and take the shape of its container may not completely filled the container because definite volume.

Liquids  Because of the way the particles of a (l) are packed, (l) are virtually incompressible. Like (s), (l) tend to expand when heated.

Liquid Examples Particle Movement

Gases A (g) is a state of matter that flows (fluid) to conform to the shape of its container and fills the entire vol. Particles very far apart (compressible) moving very fast (high KE)

Gases Gas: a sub that is naturally in the gaseous state at room temp.(oxygen gas) Vapor:the gaseous state of a sub that is a (s) or a (l) at room temp. (water vapor) e.g. steam is a vapor because at room temp water exists as a (l). (steam is invisible)

Gas Particle Movement Examples

Gases subs can change physical states e.g. water changes to steam condensation: vaporization: evaporation: *melting—not involving gas sublimation:

Ice at -60°C (Ice) temp increasing All vapor All water (l) vaporizing water(l) temp increasing (d) (100°C) Temp increasing All ice 0°C (c) Boiling water & vapor at 100°C melting All water(l) 0°C (b) (0°C) Ice+water 0°C (a) (Ice) temp increasing Ice at -60°C

Heating curve of water

Kinetic Energy and Temperature Absolute zero (0 K, or –273°C) temp at which the motion of particles theoretically ceases. Particles would have no KE. Absolute zero has never been produced in the lab. (on earth)

Gases Kinetic Theory for gases The theory makes the assumptions about the size, motion, and energy of (g) particles.

Kinetic Theory and a Model for Gases kinetic → motion. Kinetic Energy energy an object has because of its motion. all matters (of different physical states) consist of tiny particles that are in constant motion.

Kinetic Theory for Gases Assumptions for gases (1)Particles in a (g) are separated by empty spaces. (2) vol of the empty space is much > than the total vol of the (g) particles. total vol of particles ≈ 0. (3) Since (g) particles are far apart and are so light → inter-molecular attractive forces ≈ 0.

Kinetic Theory for Gases (4) (g) particles are in constant, random motion in a straight line until they bump into something (another particle or the side of a container); only change direction; continue to move … (5) All collisions among particles in a (g) are perfectly elastic. An elastic collision A collision in which KE is transferred w/o loss from one particle to another.

Particle Energy Temperature a measure of the average KE of the particles in a sample of matter. At higher temp gas particles absorbed heat energy higher KE → move faster higher pressure (gases)?? At a given temp, all (g) have the same average KE.

Particle Energy The velocity of a particle includes both its speed and its direction. Each particle in a sample containing only one (g) will have the same mass but not the same velocity.

Gas Pressure (1) Gas pressure When (g) particles collide with the walls of their container, they exert pressure on the walls. (pressure depends on the mass of (g) ) Pressure is force (N) per unit area (m2). --N/m2 Vacuum An empty space with no (g) particles and no pressure. (no collision) Atmospheric pressure pressure exerted by the particles in the atm that surrounds Earth.

Gas Pressure (5) The SI unit of pressure is the pascal (Pa). One standard atmosphere (atm) is the pressure required to support 760 mm of Hg in a Hg barometer at 25°C. Barometer ….. = 1 torr

Gas Pressure (4) A barometer is a device that is used to measure atm pressure.

Phase Changes that Require Energy (2) vapor If a sub is usually a (l) at room temp (as water is), the (g) phase. Vaporization the process by which a (l)changes into a (g) or vapor. Evaporation vaporization occurs only at the surface of a (l) at any temperature (not boiling)

Phase Changes condensation ↔ vaporization sublimation↔ deposition freezing ↔ melting

Fluidity Fluids: (l) and (g) Fluidity is the ability to flow. (l) are less fluid than (g).

Liquid-vapor Equilibrium Sealed container evaporation Evaporation and condensation equilibrium At Eqm, Rate (l)→ (g) = rate (g)→ (l) Evaporation rate = Condensation Rate

Solids Liquids Gases volume Shape density Position of particles compressibility Inter-molecular attraction Particle motion Space between particles KE of particles Arrangement of particles

melting↔freezing Vaporization↔condensation Sublimation↔deposition

Phase Diagrams Triple point Critical point

Phase Changes on phase diagram Sublimation↔deposition Melting (fusion)↔freezing Vaporization↔condensation

CST example 1 In a sealed bottle that is half full of water, eqm will be attained when water molecules A cease to evaporate. B begin to condense. C are = in # for both the (l) and the (g) phase. D evaporate and condense at = rate

CST problem 2 Under the same conditions of pressure and temperature, a liquid differs from a gas because of the molecules of the liquid A have no regular arangement B are in constant motion C have stronger forces of attraction between them. D take the shape of the container they are in.

CST problem 3 Methane (CH4) gas diffuses through air because the molecules are A moving randomly. B dissolving quickly. C traveling slowly. D expanding steadily

CST problem 4 When someone standing at one end of a large room opens a bottle of vinegar, it may take several minutes for a person at the other end to smell it. Gas molecules at room temperature move at very high velocities, so what is responsible for the delay in detection of the vinegar? A the increase in the airspace occupied by vinegar molecules B the chemical rxn with nerves, which is slower than other sensory process C attractive forces between the air and vinegar molecules D random collisions between the air and vinegar molecules

CST problem 5 If the attractive forces among (s) particles are less than the attractive forces between the (s) and a (l), the (s) will A probably form a new precipitate as its crystal lattice is broken and re-formed. B be unaffected because attractive forces within the crystal lattice are too strong for the dissolution to occur. C begin the process of melting to form a (l). D dissolve as particles are pulled away from the crystal lattice by the (l) molecules.

CST problem 6 The random molecular motion of a substance is greatest when the substance is A condensed. B a liquid. C frozen D a gas

A water at 0°C is colder than (l) nitrogen and freezes. CST problem 7 The boiling point of (l) nitrogen is 77 K. It is observed that ice forms at the opening of a container of (l) nitrogen. The BEST explanation for this observation is A water at 0°C is colder than (l) nitrogen and freezes. B the nitrogen boils and then cools to form a (s) at the opening of the container. C water trapped in the (l) nitrogen escapes and freezes. D the water vapor in the air over the opening of the (l) nitrogen freezes out.

The End