Thermodynamics 2 Flashcards

Terms Definitions
constant pressure
constant heat
Temperature in Kelvin
0⁰C -> ?K
measuring heat
1000J=1 kJ
Frist law of thermodynamics
device that does work
(thermodynamics) a thermodynamic quantity representing the amount of energy in a system that is no longer available for doing mechanical work
Quasi-equilibrium process
(see quasi-static process).
Isometric process
(see isochoric process).
number of microstates
W stands for
Semiconductor type thermometers are called ____________.
the measurement of heat-related constants such as specific heat or latent heat.
volume constant but pressure changes
Exothermic Process
Releases heat to surroundings.
(-) Delta H
Heat evolved
More Stable
Classify rxns:
&#916;H&gt;0 system absorbs energy-endothermic&#13;&#10;&#916;H&lt;0 system loses energy-exothermic&#13;&#10;&#916;S&gt;0-disorder inc&#13;&#10;&#916;S&lt;0-disorder dec
Calculate ∆G
where ∆H is the change in the system's enthalpy, ∆S is the change in the entropy, and T is temperature.
Eurkaryote Cell Divison
4 steps of Mitosis.
overcoming of resistance through a distance (ft.-lbs)
the basic unit of thermodynamic temperature adopted under the Systeme International d'Unites
Electromagnetic Energy
The energy associated with electricity, magnetism, and electromagnetic waves.
well-insulated container in which a reaction occurs to minimize heat transfers to the surroundings
Cold-air-standard assumption
combines the air-standard assumptions with the assumption that the air has constant specific heats whose values are determined at room temperature (25°C, or 77°F).
Converting amu to Joules
1atm-L = 101.3J
positive work
system does work on surroundings
State Functions
A quantity determined independent of the path chosen
a temperature scale with the freezing point of water 32 degrees and the boiling point of 212 degrees
An isothermal process has no thermal interaction with its surroundings. True or False.
energy transferred to or from system as heat (variable)
(physical chemistry) a fourth state of matter distinct from solid or liquid or gas and present in stars and fusion reactors
natural gas
composed of methane, ethane, propane, and butane
heat absorbed or released from a chemical reaction under constant pressure
heat is absorbed from surroundings (+q value = gaining heat)
Normal components
are components that are perpendicular to the quantity in question.
Externally reversible
process has no irreversibilities to occur outside the system boundaries during the process. Heat transfer between a reservoir and a system is an externally reversible process if the surface of contact between the system and the reservoir is at the temperature of the reservoir.
state function
measures the energy change between initiation and termination, regardless of path. These include energy (E), enthalpy (H), Gibbs free energy (G), and entropy (S). Heat and work are not state functions.&#13;&#10;
Charles Law
States that under a constant pressure, the volume of a gas is directly proportional to the temperature of the gas on the absolute temperature scale.
Volume= Constant x Temperature
AKA Gay-Lussac's Law
Must be expressed in form of Kelvin
Calvin cycle
occurs in the mesophyll cell in photosystem II & I
formula for enthalpy
deltaH of rxn= sigma n deltaH(products)-sigma n deltaH(reactants)
Energy added to the system by work done on it is removed from the system as heat (process)
The study of how energy behaves and interacts with matter
heat of solution (∆Hsol'n)
heat absorbed/released by dissolving one mole of a substance
(C) A metric unit of thermal energy; the amount of energy needed to raise the temperature of one gram of pure water by one degree Celsius
Mollier diagram
after the German scientist R. Mollier (1863-1935), is the plot of property data on the h-s diagram. The Mollier diagram is useful when solving isentropic, steady flow process problems dealing with nozzles, turbines, and compressors.
is any change that a system undergoes from one equilibrium state to another. To describe a process completely, one should specify the initial and final states of the process, as well as the path it follows, and the interactions with the surroundings.
Wilson line
is the locus of points where condensation will take place regardless of the initial temperature and pressure as steam flows through a high-velocity nozzle. The Wilson line is often approximated by the 4 percent moisture line on the h-s diagram for steam. Therefore, steam flowing through a high-velocity nozzle is assumed to begin condensation when the 4 percent moisture line is crossed.
Maxwell relations
are equations that relate the partial derivatives of properties P, v, T, and s of a simple compressible system to each other.
Subcooled liquid
has a temperature less than the saturation temperature corresponding to the pressure.
is a process during which heat is transferred to a thermal energy storage device (called a regenerator) during one part of the cycle and is transferred back to the working fluid during another part of the cycle.
Vacuum freezing
is the application of vacuum cooling when the pressure (actually, the vapor pressure) in the vacuum chamber is dropped below 0.6 kPa, the saturation pressure of water at 0°C.
implies no change with location over a specified region.
Saturated vapor line
is the saturated vapor states connected by a line that meets the saturated liquid line at the critical point, forming a dome.
Steam power plant
is an external-combustion engine in which steam (water) is the working fluid. That is, combustion takes place outside the engine, and the thermal energy released during this process is transferred to the steam as heat. A turbine in the power plant converts some of the energy of the steam into rotating shaft work.
Direct Way
thermodynamics is based on facts of experience that have never been proven in a ........
when a 4 C water is cooled it
power transfer into or out of control volume due to work
+ Delta S
More products are formed and more disorder
1st Law
States that the energy supplied to the system in the form of heat, minus the work done by the system in the form of heat, is equal to the change in internal energy.
TriangleU- Change in Internal Energy
Q- Heat added to the system
W- Work done by system
Electron Transport Chain
located inside of the inner membrane of the mitchondria.
a property that depends on the type of matter in a sample, not the amount of matter
gibbs free energy
the measure of spontaneity in a reaction
Intensive Property
One that is independent of the extent or total mass of the system. Intensive Properties are characteristic of the system as a whole or any part of it (Ex. Density, Temperature, Pressure)
rotational motion
rotation of the molecule on or about an axis or rotation about (?) bonds
English system,
which is also known as the United States Customary System (USCS), has the respective units the pound-mass (lbm), foot (ft), and second (s). The pound symbol lb is actually the abbreviation of libra, which was the ancient Roman unit of weight.
Enthalpy of vaporization
(or latent heat of vaporization) is the quantity hfg listed in the saturation tables.
Saturated air
is air that cannot hold any more moisture at its state.
Inert gas
is a gaseous component in a chemical reaction that does not react chemically with the other components. The presence of inert gases affects the equilibrium composition (although it does not affect the equilibrium constant).
Prandtl-Meyer function
is the angle through which flow must expand, starting with the function value of zero at Ma = 1, in order to reach a supersonic Mach number, Ma > 1.
Ton of refrigeration
is the capacity of a refrigeration system equivalent to the energy that can freeze 1 ton (2000 lbm) of liquid water at 0°C (32°F) into ice at 0°C in 24 h. One ton of refrigeration is equivalent to 211 kJ/min or 200 Btu/min. The cooling load of a typical 200-m2 (2153-ft2) residence is in the 3-ton (10-kW) range.
Package icing
is the practice of using ice in product packages to remove heat and keep the products cool during transit by taking advantage of the large latent heat of fusion of water commonly, but its use is limited to products that are not harmed by contact with ice and the moisture provided by the ice.
Energy (E)
condition of the system that allows it to do work. includes potential energy and kinetic energy
How is geopotential height found?
Using geopotential meters which are proportionally larger than a "real" meter
What Need to Know
For Boyles, Charles, and Ideal Gas Laws
You do not need to memorize these formulas in order to use them for a problem
You do need to know what the law states. If you quote is inaccurately, it is not the same... therefore incorrect!
heat of combustion
the energy released as heat by the complete combustion of one mole of a substance.
Hess's Law
You can find the heat of reaction for a process by manipulating data from related reactions
First Law of Thermodynamics
deltaU=Q-W (Internal energy, U, is the measure of all the energy, potential and kinetic, possessed by molecules in a system. It can be increased by doing work on it or by adding heat.
1 calorie
1 food calorie = 1 kilocalorie = 1000 chemistry calories
Total energy
Eof a system is the sum of the numerous forms of energy that can exist within the system such as internal (sensible, latent, chemical, and nuclear), kinetic, potential, electrical, and magnetic.
Exergy balance
can be stated as the exergy change of a system during a process is equal to the difference between the net exergy transfer through the system boundary and the exergy destroyed within the system boundaries as a result of irreversibilities (or entropy generation).
Adiabatic saturation process
is the process in which a steady stream of unsaturated air of unknown specific humidity is passed through a long insulated channel that contains a pool of water. As the air flows over the water, some water will evaporate and mix with the airstream. The moisture content of air will increase during this process, and its temperature will decrease, since part of the latent heat of vaporization of the water that evaporates will come from the air. If the channel is long enough, the airstream will exit as saturated air (100 percent relative humidity) at the exit temperature.
Reversible process
is defined as a process that can be reversed without leaving any trace on the surroundings. Reversible processes are idealized processes, and they can be approached but never reached in reality.
Steam generator
is the combination of a boiler and a heat exchanger section (the superheater), where steam is superheated.
Helmholtz function
a is defined as a = u - Ts.
What is the difference between thermodynamics and kinetics?
TD: spontaneous vs. nonspontaneous, describes energy changes
Kinetics: how fast
2nd Law of Thermodynamics
Energy has a quality that is constantly diminishing.
What is a subsidence inversion?
Air from higher altitude sinks and warms by compression.
Thermal efficiency
ratio of what we want to what we put in. The ratio of heat energy converted to work to the heat energy input?
1st law of thermodynamics
the law that states that energy cannot be created nor destroyed
standard free energy of formation (ΔG^0_f)
the free-energy change that occurs when 1 mole of the compound is formed from its elements in their standard states; of any element in its stable form is zero
Macroscopic forms of energy
are those a system possesses as a whole with respect to some outside reference frame, such as kinetic and potential energies.
Venturi nozzle
is a duct in which the flow area first decreases and then increases in the direction of the flow and is used strictly for incompressible flow.
+, +
Where ΔH is + and TΔS is -, ΔG is _________at a high temperature and __________ at a low temperature
Standard Free Energies of Formation
Amount of free energy required to form 1 mole of a substance from its elements
Virial equations of state
is an equation of state of a substance expressed in a series form as
Energy is a state function which means it depends only the the
current state of the system
If two substances are at the same temperature, their enthalpy...
relationship cannot be determined from the information provided.
Isentropic efficiency of a nozzle
is defined as the ratio of the actual kinetic energy of the fluid at the nozzle exit to the kinetic energy value at the exit of an isentropic nozzle for the same inlet state and exit pressure.
How are mixing ratio and specific humidity different?
w=q/1-q and q=w/1+w. w= Mv/Md and q= Mv/Md+Mv.
What is the Free Energy equation?
G = -RT ln Keq + RT ln ([P]/[R])
What is cp and how is it used?
We know from the ideal gas law that temperature can increase from an increase in volume if there is a constant pressure. This fact is used to rewrite the first law of thermodynamics. Constant pressure is 1005 J kg-1 K-1
more disorder
increase temperature
enthalpy change formula
Equations for work
forming new bonds
releases energy
Equation for gibbs energy
Interrelation/redistribution of all forms of E (mechanical, chemical, electrical, magnetic, heat).
Fan-jet engine
(see turbofan engine)
Dissolution of urea is___
Heat of Fusion (melting/freezing)
334 J/g
when H is positive
endothermic reaction
If ΔG<0 the reaction is
low disorder
when entropy is -
internal combustion engines are engines in which the piston executes four complete strokes (two mechanical cycles) within the cylinder, and the crankshaft completes two revolutions for each thermodynamic cycle.
System releases heat energy
Negative (-)
Temperature Scales
K, R, F, C
tempurature scale on which water freezes at 32 degrees and boils at 212 degrees (used in the US)
elastic collision
no energy is being lost
Energy is measured in terms of
not spontaneous
a reverse spontaneous reaction is
the energy transferred between objects due to a difference in temperature
spontaneous process
happens without any outside influence
is the saturation states located beneath the joined saturated liquid line and saturated vapor line.
In biochemical rxns, if &#8710;V=0, than &#8710;H=___
Cyclic Process
system returns to its original conditions; change in internal energy is zero. No net change in the system's internal energy
occurs when you premently alter a proteins structure with chemicals or heat.
substance that speeds up a reaction without being consumed
The branch of thermodynamics that is concerned with the study of energy changes that accompany chemical reactions.
17 kJ/g (4Cal/g)
amt of energy carbs supply
Chemical Energy
The energy associated with chemical bonds and bonding structure. This includes the energy associated with changes in phase from solid to liquid to gas.
spontaneous processes
can proceed without any outside intervention; processes that are spontaneous in one direction will be nonspontaneous in the reverse direction
is any characteristic of a system. Some familiar properties are pressure P, temperature T, volume V, and mass m. The list can be extended to include less familiar ones such as viscosity, thermal conductivity, modulus of elasticity, thermal expansion coefficient, electric resistivity, and even velocity and elevation.
System releases energy by doing work
Negative (-)
Microscopic Energy
Internal Energy U Umu specific internal energy
Radiation transfer
high energy to low energy through light waves. No direct contact
the direct transfer of heat from one substance to another substance that it is touching; the transfer of thermal energy that results from the collision of particles
Chemical reation
activation energy, needed to get any reaction going.
the ability to do work or produce heat
state of a system
its composition, temperature, and pressure
Fahrenheit Scale
a temperature scale that defines the freezing point of water as 32 degrees and the boiling point of water a 212 degrees
Pure Substance
one that has a homogeneous and invariable chemical composition, even if there is a change of phase.
Equipartition of Energy
Ideal (monoatomic) gas can have translational E in 3 independent directions (x, y, z) = 3 df.
Heat source
is a heat reservoir that supplies energy in the form of heat.
Incompressible substance
is a substance whose specific volume (or density) is constant.
is defined as an amount of energy produced by the combustion of natural gas and is equal to 29.3 kWh.
Inexact differentials
are the differential amount of change for path functions and are designated by the symbol d. Therefore, since heat and work are path functions, a differential amount of heat or work is represented by dQ or dW, respectively, instead of dQ or dW.
Convection heat transfer coefficient
is the experimentally determined parameter that is the ratio of the rate of convection heat transfer and the product of the heat transfer area and surface to bulk fluid temperature.
Open System
May exchange matter energy or both with the surroundings.
the area apart from the system beyond the boundaries
What is Avogadro's Law?
At constant temperature and pressure, number of molecules per unit volume of gas is a constant irrespective of the chemical compostion.
DNA Repair Hypothesis
Use 1 homoglous chromotid to repair another, passing on only the good DNA traits.
a measure of how hot or cold something is; specifically, a measure of the average kinetic energy of the particles in an object
Thermodynamics covers topics including
energy changes during heating and energy changes during chemical reactions
Specific Heat
Q=m.c.deltaT (Q is the heat gained or lost by an object and the change in temperature of that object (delta T). m is the mass). c is the...
Heat of Fusion
Liquid to solid or solid to liquid
Heat Capacity
amount of heat needed to raise the temperature of another substance 1degree C (how much heat in general)
Pseudo-reduced specific volume vR
is used with the generalized compressibility chart to determine the third property when P and v, or T and v, are given instead of P and T.
Spark-ignition (SI) engines
are reciprocating engines in which the combustion of the air-fuel mixture is initiated by a spark plug.
Coefficient of performance(COP)
is the measure of performance of refrigerators and heat pumps. It is expressed in terms of the desired result for each device (heat absorbed from the refrigerated space for the refrigerator or heat added to the hot space by the heat pump) divided by the input, the energy expended to accomplish the energy transfer (usually work input).
Thermal expansion
due to rise in temperature of a substance; molecules jiggle faster and move further apart.
What is pressure equal to?
In the atmosphere the pressure measured at any point is equal to the weight per unit area of the atmosphere above that point  hydrostatic balance. P= force/area and the SI unit for pressure is pascals
What is the first law of Thermodynamics?
Energy is conserved. deltaKE+deltaPE+deltaU=Q-W
Forced Convection
occurs when the flow of gas or liquid is circulated by pumps or fans
Liquefied petroleum gas LPG
is a byproduct of natural gas processing or crude oil refining. It consists mainly of propane (over 90 percent), and thus LPG is usually referred to as propane. However, it also contains varying amounts of butane, propylene, and butylenes.
Reduced pressurePR
is the ratio of the pressure to the critical pressure.
Compressibility factor Z
is a correction factor to account for deviation from ideal-gas behavior at a given temperature and pressure. Z = Pv/RT.
Kinetic Energy
type of energy that is the motion of parts
Table 1.3 &#13;&#10;+H, +S&#13;&#10;-H, -S&#13;&#10;+H, -S&#13;&#10;-H, +S
+H, +S endothermic, enthalp opp, spont when T&gt;H/S&#13;&#10;-H, -S enthalp favored, entrop opp, spont when T&lt;H/S&#13;&#10;+H, -S enthalp and entrop opp, nonspont always (endergonic)&#13;&#10;-H, +S enthalp and entrop favored (exothermic), spont @all temps
What is the hydrostatic equation for constant lapse rate and how do you use it?
Assume temperature varies linearly with height. This represents the real atmosphere the best out of the three. p(z)=p_o 〖((T_o (z))/T_o ) 〗^(g/(R_d Γ))
What is heat capacity?
Also known as specific heat. If a small quantity of heat is added to a unit mass of air and as a consequence, it temperature increases from T to T+dT. The ratio δq/dT is the heat capacity.
Specific Heat Capacity
the amount of heat need to raise the temperature of one gram of a substance one degree Celcius
Work done by Pressure
W=P.deltaV (P is pressure and V is volume)
Simple compressible system
is a system in which there is the absence of electrical, magnetic, gravitational, motion, and surface tension effects. These effects are due to external force fields and are negligible for most engineering problems.
25 Joule rule
The temperature of 1 mol of any solid metal is raised 1 K when the metal absorbs 25 J of heat
What happens to permanent gases above 100 km?
Not "well mixed", instead individual molecules follow long trajectories and often not colliding with other molecules. Gravity prevents heavier molecules from reaching higher altitude. So primarily hydrogen, helium, O and N (after solar radiation breaks O2 and N2 apart.)
Work (Thermo Definition)
Work is done on a system if the sole effect on the system could be the raising of a weight.
Exergy of the kinetic energy
(work potential) of a system is equal to the kinetic energy itself regardless of the temperature and pressure of the environment.
When can you use the hypsometric equation?
To derive the heights of pressure levels from measured temperature and humidity profiles.
Flow work, or flow energy
is work required to push mass into or out of control volumes. On a unit mass basis this energy is equivalent to the product of the pressure and specific volume of the mass Pv.
Exergy balance for a control volume
is stated as the rate of exergy change within the control volume during a process is equal to the rate of net exergy transfer through the control volume boundary by heat, work, and mass flow minus the rate of exergy destruction within the boundaries of the control volume as a result of irreversibilities.
Why is carbon dioxide a very important gas?
It plays a crucial role in terrestrial life: important for plants and early earth history  biochemical cycles and it plays a major role in atmospheric energy balance. Global warming crap.
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