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What are the 3 Phases of Matter (clarify volume, shape and mobility of particles for each)
- Gas: unconfined, has neither a definite volume nor shape. Each particle moves freely through space
- Liquid: has a definite volume but not a definite shape. Weak bonds permit motion while keeping the particles close together
- Solid: has a definite volume and shape. It consists of atoms connected by spring like molecular bonds
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In gas, the particles are in _______ motion and interact only through ______ _______.
In a liquid, the particles have _____ bonds that keep them close together. The particles can slide around each other, so the liquid can flow.
In a rigid solid, the particles are connected by relatively ______ ______-like bonds
- random motion
- elastic collisions
- weak
- stiff spring-like bonds
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Atomic mass number A:
A = number of _____ + number of _______
Atomic mass scale: defines the mass of 12C to be exactly ____u
Atomic mass unit u:
1u = __________
Avogradro's Number NA:
The number of basic particles per mole of substance
NA = __________
- A = number of protons + number of neutrons
- 12u
- 1u = 1.66*10-27kg
- NA = 6.02*1023mol-1
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Define Molar mass of a substance
Molar mass of a substance, Mmol: the mass in grams of 1 mol of substance
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What are two ways for finding the number of moles in a substance n:
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Define Volume
Volume: the amount of space the system occupies
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- 3) O2 n = 120/32 = 30/8 = 15/4
- 1) He n = 20/4 =5
- D.
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Three characteristics of an Ideal gas model
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The average translational kinetic energy of the molecules in an ideal gas is _______ proportional to the temperature of the gas. State the formula Kavg
- directly proportional
- Average translational kinetic energy
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The thermal energy of an ideal gas consisting of N atoms is the sum of the _______ _______ of the individual atoms.
State the formula for the thermal energy for an Ideal Gas and change in thermal energy of an ideal gas
- kinetic energies
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Define Gas pressure and state the formula
- Gas pressure is defined as the force-to-area ratio
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Gas pressure is a property of the _____ itself, independent of the _______.
State the SI unit for pressure and its conversion factor
- gas
- surface
- pascal (Pa)
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Each collision exerts a _____ on the wall. The _____ _______ due to all the collisions causes the gas to have a pressure. The force of any one collision is incredibly _____, but the number of collisions each second is exceedingly ______, so the pressure can be ________
- force
- net force
- small
- large
- considerable
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Increasing the temperature of the gas means the particles move at ______ speeds. They hit the walls more often and with more force, so there is more _______. In other words, _______ is proportional to ______
- higher speeds
- pressure
- Pressure to temperature (of the gas) (p ☛ T)
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Decreasing the volume of the container means more frequent _______ with the walls of the container and thus more _______. In other words, pressure should be ______ ______ to the volume of the container
- collisions
- pressure
- inversely proportional (p ☛ 1/V)
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Increasing the number of particles in the container means _____ frequent collisions with the walls of the container, and thus _____ pressure. What is the proportionality?
- more
- more
- Pressure is proportional to number of gas particles (p ☛ N)
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State the three Ideal gas laws
- Law I: pressure is directly proportional to temperature (p ☛ T)
- Law II: pressure is inversely proportional to volume (p ☛ 1/V)
- Law III: pressure is directly proportional to the number of particles (p ☛ N)
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The Ideal gas law is often expressed in terms of the total number of molecules, N, present in the sample.
State the formula (2) for pV in both Physics and Chemistry terms
State the gas constant (3)
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For the other forms of gas law show what is constant in:
Boyle's law
Charles' law
Guy-Lussac's law
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State the standard temperature (K & C) and pressure (atm, N/m2, kPa) as well as the volume of (1 mole of) an ideal gas
- T = 273K (0°C)
- p = 1.00 atm = 1.013*105 N/m2 = 101.3 kPa
- V (1 mol of an ideal gas) = 22.4 L
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Ideal gas's temperature is always measured in _______ and p must be the absolute pressure in _______.
If the amount of gas does not change what equality can be stated:
- Kelvins
- Pascal
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- Balloon D = 30cm & r = .15 m (SI unit)
- T = 63F = 290K
- n = m/Mmol = N/NAp(1atm or 1.015*105Pa) V(sphere = 4/3πr3) =n*R(constant) T(290K)
- n = .593 mol
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For an ideal gas in a sealed container with a piston on top, n is _______. Knowing p and V, T can be calculated from the _____ _____ _____. Thus each point on a pV diagram specifies the ______ of the gas (p, V, T).
- constant
- ideal-gas-law
- state
- *A process can be represented by a path on this diagram
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Define Work
Work: the energy transferred between a system and the environment when a net force acts on the system over a distance
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The sign of the work is neither just an arbitrary convention, nor does it have anything to do with the choice of coordinate system. The sign of the work tells us which way energy is being ________.
Work done by environment = ____________
W is the work done on system by the _________
- transferred
- -(Work done by system)
- environment
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When is work > 0 and when is it < 0
- W > 0: energy is entering the system, system's energy increases
- W < 0: energy is leaving the system, system's energy decreases
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The ______ work done by a gas equals the area under the ____ curve, evaluated between the ______ and _____ states.
- mechanical
- PV curve
- initial and final states
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Wgas = ?
For an ________ gas, Vf > Vi, the gas does ______ work
Wenviron = ?
For a _______ gas, Vf < Vi, the gas does _______ work
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Several processes can change the temperature of an ideal gas. Since ΔT is the same for each process, ____ is also the same. The heat is different for the different paths (explain).
Label the diagram
- ΔEth
- The heat associated with a particular change in temperature is not unique
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We define specific heats for two processes that frequently occur:
Changes with ______ ______
Changes with ______ ______
- constant pressure
- constant volume
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Using the number of moles, n, we can define molar specific heats for these processes:
State the formula for constant volume and pressure (processes):
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___ work is done in an isovolumetric process (w = __). Internal energy is a state function (explain).
- NO work is done
- w = 0
- Does not depend on the path followed
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What is the formula for change in internal energy for all monoatomic gases. What two other iterations of this formula come into play when you take the First Law into account. All the added energy goes into increasing the __________ ________ ________ of the atoms, thus CV = ? =?
- translational kinetic energy
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State the formula for molar specific heats at both constant volume and constant pressure
Work done on the gas in an isobaric process, W = _____.
Internal energy is a state function (explain)
- Q = nCVΔT (constant volume)
- Q = nCPΔT (constant pressure)
- W = -pΔV
- Does not depend on the path
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What is the change in internal energy (4)
Using ideal gas law:
nCVΔT = _______ minus _______
CP - CV = ___
This expression applies to any ____ ____
- ideal gas
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- Cp = Cv +R = 5/2R (monatomic)
- constant pressure takes up more energy (Q)than constant volume
- 3 degrees of freedom: x,y,z
- -Each degree of freedom is 1/2KBT
- -For diatomic = 5/2R = CV
- -For triatomic = 7/2R = CV
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A system could exchange energy with the environment through two different means, ______ and _____. When energy has been transferred as a result of a temperature difference, we call this energy _____ (Define).
- work and heat
- heat
- Heat: energy transferred between two objects at different temperatures
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Heat always flows _______ in the sense that energy is transferred from a ______ object to a ______ object
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When an ideal gas in a sealed container with a piston on top, typically KE = ____ = ____, the only form of energy present is thermal energy.
Therefore, E internal = _______ to indicate the total ______ energy of the system
- KE = PE = 0
- Einternal = Ethermal
- total internal energy
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For systems in which only the ______ energy changes, the change in ______ energy is equal to the energy transferred into or out of the system as ______, ______ or _____: (State as equation)
- thermal energy
- thermal energy
- work W, heat Q, or both
- ΔEth = Q + W
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W is the work done by environment to system:
W > 0: energy is _____ the system
W < 0: energy is _____ the system
Q is the heat transferred from environment to system:
Q > 0: heat is ______ in the system
Q < 0: heat is ______ in the system
- entering
- leaving
- increased
- decreased
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For processes in which no heat is exchanged between the gas and the environment, (Q=0):
1) For an ________ gas, Vf > Vi, ______ < 0, thus ΔEth < 0, gases _____ _____
2) For a compressed gas, Vf < Vi, ______ > 0, thus ΔEth > 0, gases _____ _____
This is the principle behind how a steam engine, refrigerator, and air conditioner work
- expanding gas
- Wenviron < 0
- gases cool down
- compressed gas
- Wenviron > 0
- gases warm up
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Name the 6 different Ideal Gas Processes (clarify any involving constants)
- Isobaric Process - constant pressure
- Isochoric Process - constant volume
- Isothermal Process - constant temperature
- Adiabatic Process
- Free Expansion Process
- Cyclic Process
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