Kinetic Theory, Gas Laws & Stoichiometry

Kinetic Theory, Gas Laws & StoichiometryI. Kinetic (molecular) Theory explains properties of (s), (l), (g), in terms of forces between particles & the E they possess..the MOTION of the particles it says that particles (atoms & molecules) are in constant motionVid KMT

A. Phases or state of matter1. matter composed of tiny particles

2. particles in constant motion

3. total E of colliding particles remains constant (some particles lose E & some gain E in collisions .the collisions are ELASTIC which means they dont lose any kinetic energy)

B. Kinetic Energy (KE) is the energy due to motion.1. KE = mv2

2.Units are Joules. kgm2/s2

C. 2nd Law of Motion 1. The acceleration produced by a net force is directly proportional to the force that caused it & in the same direction. (if F then a )

AND

Force, mass, & acceleration2.The acceleration produced by a force is inversely proportional (if m then a)to the mass of the object.

3. a = F/m or F = ma m = F/a

II. Gases & the Kinetic TheoryA. Gas particles are far apart relative to their size

B. Collisions between gas particles & container (cause pressure) are elastic

C. Gas particles are in continuous rapid, random motion (they have lots of KE!)

D. No forces of attraction between gas particles (no IMFs)

E. Average KE of gas particles depends on the Temperature of the gas

KE = mv2

KE = mv21 . Since m is the mass of the particle & all the particles of a specific gas have the same mass then the KE is completely dependent on the speed of the particle.

*** so an increase in Temp means an increase in speed & vice versa

2. All gases at the same temp have the same avg KE SO lighter gas particles have higher avg. speeds than heavier gas particles.Look at your chart that shows the sizes of the atoms

Characteristics of GasesGases expand to fill any container.random motion, no attractionno set shapeGases are fluids (like liquids).no attractionGases have very low densities.no set volume = lots of empty space

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

10III. Characteristics of gasesan IDEAL gas is an imaginary gas that perfectly fits all the rules of the kinetic theory..

a REAL gas does not behave completely according to the rules of the kinetic theory, but this is usually only noticeable at extreme pressure & low temp

A. Gases are easy to expand (volume)---gas molecules dont strongly attract each other

B. Gases are easy to compress --- gas molecules dont strongly repel each other

C. Gases have densities that are about 1/1000 of their solid or liquid densities ---gas molecules are much farther apart in gases than in liquids or solids

Characteristics of GasesGases can be compressed.no set volume = lots of empty spaceGases undergo diffusion & effusion.random motion

Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem

13D. Gases completely fill their containers --- gas molecules are in constant motion1. fluidity gas particles glide easily past each other or FLOW

E. Hot gases leak through holes faster than cold gases --- the hotter the gas, the faster the molecules are moving

1. diffusion random movement of particles from an area of greater concentration to an area of lesser concentration2. effusion process through which gas particles pass through a small openingVid review gases