Chapter 5 Test Flashcards
What is conduction?
Conduction is the transfer of thermal energy by collisions between the particles that make up matter
What is convection?
Convection is the transfer of thermal energy by a fluid due to differences in the fluid’s density
What is radiation?
Radiation is the transfer of energy by electromagnetic waves such as light and microwaves
What is temperature?
Temperature is the measure of the average kinetic energy of the particles/atoms in an object or matter
What is heat?
Heat is the energy that is transferred between objects/areas due to temperature differences between those objects/areas
What is specific heat?
Specific heat is the amount of energy needed to change the temperature of 1 Kg of a substance by
1°C
What is thermal energy?
Thermal energy is the sum of the kinetic energy and potential energy of all particles in an object.
What is thermodynamics?
Thermodynamics is the study of thermal energy, heat, and work
What is thermal expansion?
Thermal expansion is when an objects temperature increases, its volume increases as well
The Kinetic theory of matter is an explanation of…
how atoms in matter move/act/behave
Conductors are materials in which…
electrons can move freely
an insulator is a material in which _____ and _____ are _____
electrons and thermal energy
not able to move easily
Density is…
the mass per unit volume of an object
Thermal equilibrium is when 2 or more areas or objects come in contact with one another, ___ will always … until both objects…
-energy
-be transferred from the object with the higher temperature to the object with the lower temperature
-both objects reach the same temperature
Mass is the _____ in an object
amount of matter
A fluid is any substance in which its _____ can _____ and therefore, _____
particles
move past one another
change their shape
Viscosity is…
a fluid’s resistance to flowing
R-value is the _____ of the material at…
effectiveness
stopping the flow of heat
Matter is anything that _____ and _____
takes up space and has mass
Absolute zero is a ___ temperature at which…
theoretical
all particle/atomic motion in matter would stop
A heat engine is a device that converts some _____ into _____
thermal energy
mechanical energy
What are the specific heats?
water:
wood:
sand:
carbon:
iron:
water: 4,200 J / Kg x °C
wood: 1,700J / Kg x °C
sand: 830 J / Kg x °C
carbon: 710 J / Kg x °C
iron: 450 J / Kg x °C
What is the change in thermal energy formula?
Q = m (Tf - Ti) C
What are the three parts of the kinetic theory of matter?
1) all matter is composed of small particles called atoms
2) the atoms in matter are in constant, random motion
3) the atoms in matter are colliding into one another transferring energy
What is the 1st Law of Thermodynamics?
mechanical energy will be constant but if energy changes work must be done on the system or energy must be added to the system
What is the 2nd Law of Thermodynamics?
This law deals with entropy, saying that energy over time will change forms and become less useful. This law also states that energy will spontaneously spread from an area of higher concentrations to areas of lower concentrations which causes an increase in entropy.
What is the 3rd Law of Thermodynamics?
absolute zero
the slowing of particle motion as this theoretical temperature is reached
Entropy is decreased
What is the 0th Law of Thermodynamics?
This law deals with thermal equilibrium, saying that if a 3rd object is introduced to 2 other objects already at thermal equilibrium the 3rd object will reach thermal equilibrium with the other 2 objects.
What is the difference between an isolated and non-isolated system?
isolated: no energy transfers between that system and its surroundings
non-isolated: does have energy transferred between the system and its surroundings
What are the three ways thermal energy is transferred?
conduction
convection
radiation
What are the 4 types of heating systems?
forced-air
radiators
electric
solar
How do forced-air heating systems work?
furnace heats air that is then sent through ducts and out vents
How do radiators work?
a boiler heats water which makes steam
piped to radiators in rooms
How do electric heating systems work?
electricity heats metal coils
coils heat air that is then blown out by a fan
How do solar heating systems work?
What is the efficiency of heat engines?
25%
What happens in the first stroke of a 4-stroke cycle engine?
intake
intake valve opens
piston moves downward and draws a gasoline air mixture down into the cylinder
What happens in the second stroke of a 4-stroke cycle engine?
compression
the intake valve closes
piston moves upward compressing the fuel air mixture
What happens in the third stroke of a 4-stroke cycle engine?
power
spark plug ignites fuel air mixture
as the mixture burns the hot air gases expand pushing the piston down
What happens in the fourth stroke of a 4-stroke cycle engine?
exhaust
as the piston moves up, the exhaust valve opens
and the hot gasses are pushed out of the cylinder
How does a refrigerator work?
- liquid coolant goes through expansion valve where
the coolant decreases in pressure and temperature - coolant absorbs thermal energy from inside
refrigerator while going through evaporator coils
and becomes a gas - It then enters the compressor and becomes
compressed causing the pressure and temperature
to increase - coolant goes through the condenser coils where
the gas releases thermal energy into the
environment causing the coolant to return to a
liquid state
What energy conversions happen in heat engines?
chemical
thermal
mechanical
What is the difference between conduction, convection, and radiation?
conduction and convection need matter, radiation does not
convection transfers matter and energy but, conduction only transfers energy
_____ means rapid burning
active combustion
a heat pump is a _____
two way heat mover
a device on a building that absorbs radiant energy from the sun is _____
solar collector
to measure specific heat, use a _____
calorimeter
the most common state of matter in the universe is _____
plasma
What is the difference between an internal combustion engine and an external combustion engine?
an internal combustion engine burns fuel inside the engine
an external combustion engine burns fuel outside the engine
What is the temperature of the boiling point of water?
212°F 100°C 373K
What is the temperature of human body temperature?
98.6°F 37°C 310K
What is the temperature of room temperature?
68-72°F 20-22°C 293-295K
What is the temperature of the freezing point of water?
32°F 0°C 273K
