Exam 2: Gas Laws Flashcards

1
Q

Kinetic Theory of Matter

A
  • prediction of how matter should behave (based on assumptions/approximations; helps explain the differences between the three states of matter)
  • all matter is made up of moving particles (molecules/atoms)
  • phase changes occur with increases in kinetic energy in matter (usually in the form of heat)
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2
Q

What type of movements do you typically see in solids?

A

vibrations

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3
Q

What do you see in terms of movement in a liquid?

A

particles have free space to move but are still attracted to each other (liquids have a less defined shape)

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4
Q

Explain the movement you would see in gases?

A

gas particles are farther apart (more distance = less interaction) so they can move freely (less intermolecular interactions)

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5
Q

What are the characteristics of gases?

A
  • physical properties of gases are all similar
  • composed mainly of nonmetallic elements with simple formulas and low molar masses
  • two or more gases form a homogeneous mixture (won’t see layering of gases)
  • molecules move independently with no forces keeping them together or pushing them apart
  • gases expand to fill their containers, are highly compressible, and have extremely low densities when compared to water
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6
Q

List the components of the kinetic theory of gases

A
  • gases have large numbers of molecules in a continuous and random motion
  • energy can be transferred between molecules during collisions but the average number of kinetic energy does not change as long as the temperature stays constant
  • average kinetic energy is only dependent on the temperature
  • gas is compressible into a liquid (volume of molecules of gas relative to volume in which gas is contained is negligible)
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7
Q

Molecular speed is

A
  • temperature is related to the average kinetic energy
    average kinetic energy quantifies the speed the gas particles move
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8
Q

µ rms means:

A
  • root mean-squared speed
  • associated with average kinetic energy
  • changes to temperature (energy) will change the velocity (speed)
  • low molar mass = faster speed
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9
Q

Temperature is converted to what? (include conversion)

A

Kelvin (standard unit of measurement)

Kelvin = C + 273

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10
Q

Pressure is converted to what? (include conversion)

A

given in atmosphere (atm, standard unit of measurement)

1 atm =14.696 PSI 760 mmHg

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11
Q

Volume is given in what?

A

L (liters)

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12
Q

The amount of gas is given in what?

A

moles (mol)

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13
Q

Define pressure.

A

the amount of force applied to an area

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14
Q

Define atmospheric pressure

A

the weight of air per unit of area (atm)

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15
Q

If you increase the pressure, gas becomes _____ soluble in the blood

A

more

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16
Q

Boyle’s Law

A
  • PV
  • pressure of a gas is INVERSELY related to its volume when temperature is constant
  • if volume decreases, pressure increases
  • P1V1 = P2V2
17
Q

Charles’s Law

A
  • VT
  • temperature of a gas is directly related to the volume
  • pressure and amount of gas are constant
  • if the temperature increases, the volume increases at a constant pressure
  • V1/T1 = V2/T2
18
Q

Gay-Lussac’s Law

A
  • PT
  • pressure exerted by a gas is directly related to the temperature of the gas
  • volume and amount of gas are constant
  • if the temperature decreases, the pressure decreases
  • P1/T1 = P2/T2
  • explains why water boils at lower temps at higher elevations
19
Q

Combined Gas Law

A
  • combines all 3
  • uses the pressure-volume-temperature relationships where n is constant
  • P1V1/T1 = P2V2/T2
20
Q

Avogadro’s Law

A
  • amount and T
  • volume of gas is directly related to the amount (number of moles) where temperature and pressure are constant
  • if amount (n) of gas increases, then the volume increases
    V1/n1 = V2/n2
  • at a standard temperature and pressure (STP; 1 atm, 273K) one mole of gas occupies 22.4L
21
Q

Ideal Gas Law

A
  • combines the individual gas laws (Boyle’s, Charles’s, Avogadro’s)
  • PV = nRT (R = 0.08206 L x atm/mol x K)
22
Q

Dalton’s Law

A
  • partial pressures
  • if two gases that no not react are combined in a container, they act as if they are alone in the container
  • total pressure of a mixture of gases = sum of the pressures that each would exert if they were present alone
  • Pt = P1 + P2 + P3 + …
  • amount of each gas can be related to its partial pressure
23
Q

Graham’s Law

A
  • effusion rate
  • relates the molar mass of the two gases to their rate of speed of travel
  • lower the molar mass, the faster the rate of speed
24
Q

Henry’s Law

A
  • the solubility of a gas in a given volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that of the liquid
25
Q

Van der Waals Equation (for real gases)

A
  • ideal gas law can be adjusted to take deviations from ideal behavior into account
  • can adjust pressure (due to the fact that molecules attract and repel each other)
  • can adjust volume (due to the fact that molecules occupy some space on their own)
26
Q

mole fraction

A
  • ratio of moles of a substance to total moles
  • moles of compound 1/total moles (N1/Nt)
27
Q

Can you determine the partial pressure of a gas from the mole fraction?

A
  • P1 = (N1/Nt) x Pt = X1P1
28
Q

Effusion is:

A

escape of gas molecules through a tiny hole into an evacuated space

29
Q

Diffusion is:

A

the spread of one substance throughout a space or a second substance (always occurs from areas of higher concentration/pressure to lower)

30
Q

Real gases

A
  • the behavior of gases conforms to the ideal gas law only at relatively high temperature and low pressure
  • even the same gas will show wildly different behavior under high pressure at different temperatures
  • assumptions that gases break down at high pressure and/or low temperature