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Day Read / review pages AND complete #s 3-6 AND Read / review pages AND complete #s Due Tuesday 11-1.

What do the words diffuse and effuse mean? - Use book if necessary 5-4

1. Locate your Chapter # 3 Quest. 2. Calculate and record your % grade. 3. Did you meet your goal? Why or why not. 4. Study (preparation) Plan for next test? 5. Record your new goal: - If you did not meet your goal it stays the same - If you did meet your goal – improve by one percentage points Day

Physical Behavior of Matter States of Matter Solid – rigid with a definite shape Liquid – flowing with a definite volume Gas – flowing, compressible – NO definite shape or volume

Physical Behavior of Matter Kinetic Theory of Matter Submicroscopic particles of all matter are in constant, random motion Kinetic energy – energy of motion KE = (1/2)mv 2

1. Gases consist of large #s of tiny particles that are far apart relative to their size (each particle has mass) 2. Collisions between gas particles and between particles and container walls are elastic 3. Gas particles are in constant, rapid, random motion… they possess kinetic energy Kinetic-molecular Theory - Gases

4. There are no forces of attraction or repulsion between gas particles 5. The average kinetic energy of gas particles depends on the temperature of the gas

Kinetic Theory and a Model for Gases The kinetic theory as it applies to gases includes the following fundamental assumptions about gases. The particles in a gas are considered to be small, hard spheres with an insignificant volume. –Within a gas, the particles are relatively far apart compared with the distance between particles in a liquid or solid. –Between the particles, there is empty space. –No attractive or repulsive forces exist between the particles.

Bromine molecule Kinetic Theory and a Model for Gases The kinetic theory as it applies to gases includes the following fundamental assumptions about gases. The motion of particles in a gas is rapid, constant, and random. –Gases fill their containers regardless of the shape and volume of the containers. –An uncontained gas can spread out into space without limit.

Kinetic Theory and a Model for Gases The kinetic theory as it applies to gases includes the following fundamental assumptions about gases. The motion of particles in a gas is rapid, constant, and random. –The rapid, constant motion of particles in a gas causes them to collide with one another and with the walls of their container.

Kinetic Theory and a Model for Gases The kinetic theory as it applies to gases includes the following fundamental assumptions about gases. The motion of particles in a gas is rapid, constant, and random. –The particles travel in straight- line paths until they collide with another particle. –The particles change direction only when they rebound from collisions.

Kinetic Theory and a Model for Gases The kinetic theory as it applies to gases includes the following fundamental assumptions about gases. All collisions between particles in a gas are perfectly elastic. –During an elastic collision, kinetic energy is transferred without loss from one particle to another. –The total kinetic energy remains constant.

What is an elastic collision? An elastic collision is one in which kinetic energy is transferred from one particle to another with no overall loss of kinetic energy.

Gas Pressure If no particles are present, no collisions can occur. Consequently, there is no pressure. An empty space with no particles and no pressure is called a vacuum. Gas pressure is the result of billions of rapidly moving particles in a gas simultaneously colliding with an object.

Gas Pressure Air exerts pressure on Earth because gravity holds the particles in air within Earth’s atmosphere. The collisions of atoms and molecules in air with objects results in atmospheric pressure. Atmospheric pressure decreases as you climb a mountain because the density of Earth’s atmosphere decreases as the elevation increases.

Kinetic-molecular Theory - Gases Expansion Fluidity fluids = liquids and gases Low density Compressibility Diffusion spontaneous mixing Effusion gas particles under press. Pass thru tiny opening

Ideal gas – an imaginary gas that perfectly fits all the assumptions of the kinetic-molecular theory Kinetic-molecular Theory - Gases

Applies when: pressure is NOT very high and temperature is NOT very low!!! Real gases occupy space and attract one another.

1. Gases consist of large #s of tiny particles that are far apart relative to their size (each particle has mass) Kinetic-molecular Theory - Gases 2. Collisions between gas particles and between particles and container walls are elastic 3. Gas particles are in constant, rapid, random motion… they possess kinetic energy

Kinetic-molecular Theory - Gases 4. There are no forces of attraction or repulsion between gas particles 5. The average kinetic energy of gas particles depends on the temperature of the gas

Ideal gas Kinetic-molecular Theory - Gases – an imaginary gas that perfectly fits all the assumptions of the kinetic-molecular theory

Pressure Kinetic energy Ideal gas Diffuse Constant, rapid, random STP Elastic collision Effuse Atmospheric pressure vacuum

The Gas Laws Gas Laws – simple mathematical relationships between the volume, temperature, pressure, and quantity of a gas 4 variables: volume, temperature, pressure, and quantity

The Gas Laws 4 variables? volume, temperature, pressure, and quantity …

The Gas Laws 4 variables: volume, temperature, pressure, and quantity Quantity (amount) – n – measured in ________ Volume – V – measured in ________ (1L = 1000 cm 3 ) Temperature – T – measured in _________ Pressure – P – measured in … moles liters kelvins

Pressure – the force per unit area on a surface pressure = force / area barometer – measures atmospheric pressure Pressure

barometer – measures atmospheric pressure

units of PRESSURE: Millimeters of mercury (mm Hg) Atmospheres (atms) Pascals (Pa) pounds per square inch (psi) PAGE 407 Pressure 1.00 atm = 760 mm Hg = 14.7 psi = 101,300 Pa

Pressure Convert: 760 mm Hg = ___ atm 2.5 atm = ___ Pa Pa = ___ mm Hg 775 mm Hg = ___ atm

Back to STP 1 atm and K IF conditions are not specified, assume STP Applies when: pressure is NOT very high and temperature is NOT very low!!!

R

1.Define an ideal gas 2.The ideal gas works (applies) when pressure is _____________________. 3.Real gases occupy space and …