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Kinetic Molecular Theory Physical States of Matter BIOB111 Session 5…
Kinetic Molecular Theory
Physical States of Matter
BIOB111 Session 5
Energy
the ability of matter to do work
does not occupy space, has no mass
has the abililty to move/cause motion
Law of
Conservation
of Energy
energy can neither be created or destroyed
one form of energy can be converted into another form of energy
just changing where it is
Kinetic
Energy
EKIN
energy due to the motion of an object
dependent on mass and velocity
EKIN = 1/2 m x v2
any moving object that has EKIN = doing work
Potential
energy
EPOT
energy stored for later use
the energy that matter possesses as a result of its position, condition and/or composition
arises from its capacity to move or cause motion (itself or something else)
Kinetic
Molecular
Theory
the particles in a system transfer energy to each other through elastic collisions. Have to have these for a chemical reaction to occur by overcoming activation energy barrier
velocity (EKIN) of the particles increases directly with temperature increase
the particles have the capacity to interact with one another through attractions (+ and -) and repulsions (- and -, + and +), therefore possess EPOT
the particles are in constant motion and therefore possess EKIN
matter is composed of tiny particles or characteristic and defined sizes that do not change
Measurement
Calorie [cal]
metric
the amount of energy needed to raise the temperature of 1g of water (by releasing energy) by 1 degree C
1 kcal = 1,000 cal
Joule [J]
SI system
~4 times larger than cal
States of
matter
explained by the relative magnitudes of EKIN (velocity and EPOT (electrostatic attractions)
EKIN
is a disruptive force that tends to make the particles of a systems increasingly independent of one another (particles moving around and won't be close to each other)
high EKIN = particles moving everywhere
EPOT
is a cohesive force that tends to cause order and stability among the particles of the system (enhances particles being close together, cohesive and more stable)
high EPOT = particles stable
Solid
Low EKIN
- particles densely packed
High EPOT
- little movement of particles
definite shape
definite volume
particles stationary/move very slowly
particles held closely together in fixed arrangements by attractive forces (strong attractions between particles)
Liquid
Moderate EKIN
- moderate movement between particles
Moderate EPOT
- strong attraction between particles
no definite shape
definite volume
particles move faster than in solid state
particles are further apart from each other, randomly packed, but there are still attractive forces between them
Gas
High EKIN
- particles move quickly
Low EPOT
- minimal attractive forces between
no definite shape
no definite volume
high compressible and expandable
particles move very fast and randomly
particles are far apart from each other and there are minimal attractive forces between them
Properties of
Gases
#
Pressure (P)
the force that gas exerts against the walls of its container
Measurement: Atmosphere (atm) or millimeter of mercury (mmHg)
Volume (V)
the space that the gas occupies
Measurement: Litre (L)
Temperature (T)
determines EKIN and the rate of motion of gas particles
Measurement: Degree C
Amount (n)
the quantity of gas present in the container
Measurement: Gram (g) or Mole (mol)
Boyle's Law
#
#
pressure-volume relationship
the
volume
of a fixed amount of gas
is inversely proportional to the pressure
applied to the gas, at a constant temperature
as pressure increases, volume decreases
as pressure decreases, volume increases
P1 x V1 = P2 x V2
Inhalation
lung volume increases, pressure in lungs decrease
air flows from area of higher pressure (atmosphere) to area of lower pressure (lungs)
Exhalation
lung volume decreases, pressure in lungs increases
air flows from area of higher pressure (lungs) to the area of lower pressure (atmosphere)
Dalton's Law of
Partial Pressures
the
total pressure
exerted by a mixture of gases is the
sum of the partial pressures of the individual gases
present in the mixture
PTotal = P1 + P2 + P3 + ...
Changes of state
involve heating or cooling a substance
Exothermic
melting, evaporation, sublimation (S to G)
a change of state in which heat energy is absorbed
Endothermic
a change in state in which heat energy is given off
freezing, condensation, deposition (G to S)
Ideal Gas Law
#
the behaviour of gases depends on pressure (P), volume (V), number of moles, amount (n) and temperature (T)
Ideal gas equation
PV = nRT
the four variables can be combined to predict the behaviour of a gas to it's environment