Physics Ch 9 and 10
What is the ice point or melting point of water?
0° C
What is the steam point of boiling point of water?
100° C
What do phase changes result from?
A change in the potential energy between particles of a substance
What is a monatomic gas?
A gas that contains only one type of atom
What is temperature?
A measure of how hot (or cold) something is; specifically, a measure of the average kinetic energy of the particles in an object
What is convection?
A mechanism for transferring energy that involves the movement of hot and cold matter, such as hot air rising over a flame; it used the effects of pressure differences, conduction, and buoyancy
What is internal energy?
A property that includes the energies of the individual particles of the system but not the energies of the entire system
What is the coefficient of volume expansion?
A quantity that describes the thermal expansion characteristics of a material
What is a system?
A set of particles or interacting components considered to be a distinct physical entity for the purpose of study
What is internal energy proportional to?
A substance's temperature (assuming that the state does not change)
What is an adiabatic process?
A thermodynamic process in which no heat transfer between the system and its environment take place
What is a cyclic process?
A thermodynamic process in which one form of energy is partly converted unto another and the remainder is released as heat
What is an isothermal process?
A thermodynamic process that takes place at constant temperature
What is an isovolumetric process?
A thermodynamic process that takes place at constant volume so that no work is done on or by the system
What is thermal conduction?
A type of energy that is transferred and increases the temperature of an object
What usually changes temperatures?
Adding or removing energy
What is electromagnetic radiation?
Another principal energy transfer mechanism; objects reduce their internal energy by giving off electromagnetic radiation of particular wavelengths (car is heated by sunlight)
In most cases, how is energy transferred?
As both heat and work
When does a gas have a pressure of 0?
At -273.15° C, or 0 K
How do heat engines do work?
By transferring energy from a high temperature substance to a low temperature substance
What happens when matter goes through a phase change?
Energy added or removed changes the internal energy of the substance without changing the substances temperature
What occurs in an adiabatic process?
Energy is not transferred as heat, only work
What are degrees?
Equally spaced reference marks on a thermometer
What is the Celsius-Fahrenheit temperature conversion?
F=(9/5)C+32
What are the three most widely used temperature scales?
Fahrenheit, Celsius, and Kelvin
What do calibrating thermometers require?
Fixed temperatures
What is one way a substance will increase its internal energy?
Friction (or deforming a structure, in the case of solids (stretching a rubber))
How does heat move?
From an object of higher temperature to an object of lower termperature
What substances have the largest coefficients of volume expansion?
Gases
What is energy transferred between substances as?
Heat
What does the value of specific heat tell one?
How much the temperature of a given mass of a substance will increase or decrease, based on how much energy is added or removed as heat
Why does ice float?
Ice is a crystal that has more empty space than liquid water
What is the environment?
In physics, the combination of conditions and influences that determine the behavior of a system
How is potential energy present in solids and liquids?
In the form of attractive bonds, resulting from the charges
What is an effect of added energy being distributed among the particles of a substance?
Increased temperature
How does a thermometer work?
It changes temperature until it is in thermal equilibrium with the object in contact
What happens to matter as the temperature increases?
It expands
If the internal energy of a system and the energy dissipated into the surrounding air are taken into account, what happens with the total energy?
It is constant
In a constant-temperature process, what happens to internal energy?
It is constant
What can be said of the temperature of two objects in thermal equilibrium?
It will lie between the objects initial temperatures
What is the SI unit for energy?
Joules
What is the Celsius-Kelvin Temperature conversion?
K=C+273.15
What is latent heat abbreviated by?
L
What is energy transferred during phase changes?
Latent heat
What is important when determining certain thermal properties of gases?
Maintaining a constant pressure
What happens on a molecular level during thermal equilibrium?
Molecules speed up or slow down until all the particles have the same kinetic energies
In a constant-volume process, how much work is done?
None (temperature changes)
What is the difference between temperature and heat?
Objects always have temperature because the molecules are always moving, but when there is no temperature difference between two objects, there is no heat transfer
When is temperature meaningful?
Only when it is stable
(As a review) What is PE equal to?
PE=mgh
In thermodynamic terms, what is work defined in terms of?
Pressure and volume change
What is heat symbolized by?
Q (∆Q is change in heat)
Mathematically describe an isothermal process.
Q=W
What is the formula for latent heat?
Q=mL Energy transferred during a phase change=latent heat*mass
What are two examples of cyclic processes?
Refrigerators and heat engines
What two things does the equation for specific heat apply to?
Substances that absorb energy from their surroundings and substances that transfer energy to their surroundings
What are thermal conductors?
Substances that rapidly transfer heat (metals)
What are thermal insulators?
Substances that slowly transfer energy (cork, ceramics, cardboard)
For ideal gases, what does internal energy depend on?
Temperature of the gas
What happens to a system's properties in a cyclic process?
The beginning properties are identical to the end properties
What is sublimation?
The change from a solid to a vapor or a vapor to a solid
What is the only difference between the Celsius and Kelvin scales?
The choice of zero point
For each complete cycle of the heat engine, what is the net work done equal to?
The difference between the energy transferred as heat from a high-temperature substance to the engine (Q(h)) and the energy transferred as heat from the engine to a lower temperature substance (Q(c))
What does energy transfer as heat depend upon?
The difference of the temperatures of the two objects
What does energy absorbed by water in a calorimetry calculation equal?
The energy released by the substance Q(w)+Q(substance)=0 mc∆T(water)=-(mc∆T(substance))
What is heat?
The energy transferred between objects that are at different temperatures; energy is always transferred from high-temperature objects to lower-temperature objects until thermal equilibrium is reached
What is latent heat?
The heat energy that is absorbed or released by a substance during a phase change
What is an example of a heat engine?
The internal combustion engine in vehicles
What is temperature proportional to?
The kinetic energy of atoms and molecules
What is calorimetry?
The measurement of heat-related constants, such as specific heat or latent heat
What is thermal expansion?
The phenomena of as a temperature of a substance increases, so does its volume
What is phase change?
The physical change of a substance from one state (solid, liquid, or gas) to another
What is the First Law of Thermodynamics?
The principle of energy conservation that takes into account a system's internal energy as well as work and heat
What does the rate of thermal conduction depend upon?
The properties of the substance being heated
What is specific heat capacity?
The quantity of heat required to raise a unit mass of homogenous material 1K in a specific way given constant pressure and volume
What do temperature units depend on?
The scale used
What is thermal equilibrium?
The state in which all portions of a thermodynamic system are at a uniform temperature consistent with the system's surroundings
What is absolute zero?
The temperature of 0K
What is the heat of fusion?
The type of latent heat that is added to a substance during melting and equals the difference between the total potential energies for particles in the solid of liquid phases
What is the heat of vaporization?
The type of latent heat that is added to a substance during vaporization and that equals the difference in the potential energy of attraction between the liquid particles and the gas particles
What units does heat have?
The units of energy
What is similar about heat and work?
They are both terms used to define energy transferred to or from a system
How are temperature difference between two object and the rate of energy transfer related?
They are proportional (one goes up, so does the other)
What is calorimetry used for?
To determine specific heat capacity
How do heat engines use heat?
To do mechanical work
What is the symbol for internal energy?
U (∆U is change in internal energy)
Mathematically describe heat engines' cycles.
W(net)=Q(h)-Q(c)
What is the work done by a gas equation?
W=P∆V where P=F/A
What can internal energy be used to do?
Work
What are the sum of changes in potential energy, kinetic energy, and internal energy always equal to?
Zero
What is the change in internal energy during a cyclic process?
Zero
When two objects are in thermal equilibrium, what the the net energy transferred between the two objects?
Zero
What is the symbol for specific heat?
c
What is the specific heat capacity formula?
c=Q/m∆T specific heat= energy transferred as heat/mass* change in temperature
What is the equation for the conservation of energy?
∆PE+∆KE+∆U=0
Mathematically describe a cyclic process.
∆U(net)=0 Q(net)=W(net)
Mathematically describe an adiabatic process.
∆U=-W
Mathematically describe an isolated system.
∆U=0
Mathematically describe an isovolumetric process.
∆U=Q
How is the First Law of Thermodynamics expressed mathematically?
∆U=Q-W
