Chapter 5 Flashcards
Matter is made of these three things
atoms, ions, and molecules
Atoms, Ions, and Molecules are in…
constant motion in all directions at different speeds
the more kinetic energy and object has the ____ the object feels
hotter
As kinetic energy goes up, speed goes up. They have a ___ relationship
Direct
Speed and Temperature are ____ related
directly
Temperature is
the measure of the average kinetic energy of the particles that make up an object
when you move the particles that make up matter further apart, the ______ of that matter increases
Potential Energy
Thermal energy moves from areas of _____ concentration to areas of ____ concentration
High - Low
thermal energy is
the sum of the kinetic energy and the potential energy of all the particles that make up that object
potential energy, kinetic energy, and thermal energy are ____ related
directly
What two factors does thermal energy depend on
temperature and mass
Heat is
the energy that is transferred between objects due to a temperature difference between those objects
heat is measured in
joules
warm objects ALWAYS ____ cool objects but the reverse never occurs
heat
cold is
the absence of heat
a substance’s temperature change depends on these three things
the amount of thermal energy inside, the mass, and the nature of the substance
specific heat is
the amount of heat needed to raise the temperature of 1 kg of that material by 1° Celsius
specific heat is measured in
Joules per kilogram degree Celsius (J/kg°C)
water has a high specific heat because
the molecules have strong attractions
metals have low specific heat because
the electrons move throughout easily, which transfers thermal energy quickly
because water can absorb thermal energy without a large change in temperature it is useful as a ____
coolant
a coolant is
a substance that is used to absorb thermal energy
Q=
change in thermal energy
C=
Specific heat
Tf=
final temperature
Ti=
initial temperature
m=
mass
equation for calculating thermal energy changes
Q=m(Tf-Ti)C
convection moves fastest through ____
liquids
conduction moves fastest through ____
solids
radiation moves fastest through ____
gases
conduction and convection are prevented by _____ whereas radiation is not
vacuum
Conduction is
the transfer of thermal energy by collisions between particles in matter.
Conduction occurs because
particles are in constant motion
in conduction, thermal energy is transferred by _____ not by the movement of matter
collisions between particles
Conduction spreads thermal energy from ____ areas to ____ areas
warmer - cooler
the rate at which thermal energy is transferred depends on
the material
the best conductors of thermal energy are
metals
Convection is
the transfer of thermal energy throughout a fluid by the movement of warmer and cooler fluid from place to place
convection currents form when a liquid is heated from ____
the bottom
Warm liquids ___ and cold liquids ____
rise - sink
radiation is
the transfer of energy through electromagnetic waves (when matter is not present)
radiation does not require a ____
medium
when radiation occurs some of the energy is ____ some is ____ and some may even be _____
absorbed - reflected - transmitted
a forced heating system is
when a furnace burns fuel to heat the air then a fan blows the air through ducts which leads to vents (most popular type of heating system in the US)
a radiator system is
a radiator is a closed metal container that contains hot water or steam which is heated by a central furnace. The steam is then carried through the pipes to radiators in the other room ( this uses conduction and radiation because particles from the Steam Heat particles in the metal which heat particles in the surrounding air they also use convection to move the air warmer throughout the rooms)
a heating system is
when electric heating coils transform electrical energy into thermal energy and transfers heat from coils to Air then distributes warm air throughout the room
passive solar heating is
when materials inside a building absorbs radiant energy from the Sun and heat up during the day at night when the building begins to cool thermal energy absorbed by these materials help to keep the room warm
active solar heating uses
solar collectors to turn radiant energy into thermal energy. Radiation from the sun heats air or water in the solar collector by transforming radiant energy into thermal energy a pump circulates the hot fluid to radiators in rooms of the house
thermal energy, heat, and work are all ____ related
directly
the heat to a system is
the amount of thermal energy that crosses the boundary of that system
the work done to a system is
the work done by something outside the system’s boundary
the first law of thermodynamics says
the increase in thermal energy of a system equals the work done on the system plus the heat to the system
the temperature of a system can be increased by (3 things):
- adding heat to the system
- doing work on the system
- both
the increase in energy of a system ____ the energy added to the system
equals
a system is not isolated if there are
thermal energy transfers across the boundary or if work is done across the boundary
a system is isolated if there are
no energy transfers between the system and its boundaries
the thermal energy of an isolated system…..
does not change
thermal energy ____ be transferred spontaneously from a cold object to a warm object
cannot
the second law of Thermodynamics says that
energy spontaneously spreads from regions of higher concentration to regions of lower concentration
the only way that energy can move from lower concentration to higher concentration is if…
work is done
a heat engine is a
device that converts thermal energy into mechanical energy
whenever energy transformations occur some of the energy is transformed into ____
thermal energy
