6.3 Temperature and Heat Flashcards
Kinetic molecular theory of matter
states that matter is made up of particles
(molecules, atoms, ions) that are in constant
random motion
these particles are continually vibrating, rotating, and colliding with one another.
The particles that make up matter have ________ because of their constant motion.
kinetic energy
As particles _______, their energy constantly
alternates between kinetic energy and elastic
potential energy.
vibrate
Particles also have __________ energy due to the forces of attraction or chemical bonds between them.
potential
Thermal energy
the total kinetic and potential energy of the particles within an object
Thermal energy is internal energy –
the energy associated with the _______ of the particles.
movement
An object has _____ energy in addition to any potential energy or kinetic energy it may have as a
whole.
thermal
A car moving over a bridge has kinetic energy because
it is moving
A car moving over a bridge has gravitational potential energy because
it is high on the bridge
A car moving over a bridge has thermal energy because
of the particles that make up the car.
As particles move, they collide, and when they
do, they transfer ____________ back and forth
among themselves.
In this way, energy can be ________ from one part of an object to another, or even from one object to another object.
kinetic energy; transferred
The temperature of a substance is the average
_____________ of the particles.
kinetic energy
The greater the average kinetic energy of the particles, the _______ the object’s temperature.
higher
Temperature is measured in either Celsius or
Kelvin. The standard SI unit is the ______.
0° C = 273 K
Kelvin
Absolute zero
-lowest temperature that is theoretically possible
-occurs at a temperature of 0 Kelvin, or -273°C.
At absolute zero, molecular motion and energy would be _______.
minimal
_______ is the energy transferred from a warmer
object to a cooler one.
Heat
Heat is always transferred from a _____ object
to a ________ object.
hotter; colder
If two objects are the same temperature, there will be __________.
no heat transfer
However, when two contacting surfaces are
rubbed against one another, _______ exists as
the particles in the substance to move past
each other and their kinetic energy gets
transferred into _______ energy, causing a ____
in temperature.
friction; thermal; rise
Conduction
The transfer of thermal energy through direct
contact of substances.
Example: hot chocolate in a mug
Convection
The transfer of thermal energy through the
bulk movement of particles from one
location to another. This occurs in liquids and
gases. Convection is a natural stirring of a
fluid: hotter, less dense material flows up
while cooler, denser material flows down.
Eventually all the material is heated to a
uniform temperature.
Example: boiling water, air in a room.
Radiation
Radiation is the transfer of thermal energy
through fast moving particles or
electromagnetic waves.
Example: heat given off by the sun
Heat capacity (c)
the amount of thermal energy needed to change the temperature of an object or system by 1
Kelvin, or 1°C.
The amount of thermal energy (Q) you need to
heat an object depends on three things:
The mass of the object
How much temperature change you are
trying to get
The type of material (specific heat capacity)
Q =
thermal energy
m =
mass
c =
specific heat capacity
ΔT =
temperature change
the principle of heat exchange
When two substances at different
temperatures are mixed, the amount of
thermal energy lost by the hotter substance in
cooling is equal to the amount of thermal
energy gained by the colder substance in
warming.
The thermal energy gained by the cooler
substance ______ the thermal energy _____ by
the warmer substance.
equals; lost
