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13 Cards in this Set
- Front
- Back
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variables that determine the behavior of gases
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- pressure
- temp - volume - the amount of gas present when one variable changes, the other 3 are affected |
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kinetic theory assumes...
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- gas particles do not attract or repel each other
- gas particles are much smaller than the distances between them - gas particles are in constant, random motion - no KE is lost when gas particles collide with each other or the walls of the container - all gases have the same average KE at a given temp * actual gases don't obey all assumptions made, but their behavior approximates these assumptions |
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Boyle's law
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the volume of a given amount of gas held at a constant temp varies inversely with the pressure
P1V1 = P2V2 illustrated by the downward curve of a graph of P-V changes |
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Charles's law
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the volume of a given mass of gas is directly proportional to its KELVIN temp at constant pressure
this is because at higher temp the particles move faster---number and force of the collisions increases. for pressure to stay constant, the volume must increase so that the particles have farther to travel before they strike the sides of the container, which would decrease the frequency of these collisions V1/T1 = V2/T2 |
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Celsius to Kelvin conversion:
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Tk = 273 + Tc
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Gay-Lussac's law
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the pressure of a given mass of gas varies directly with the KELVIN temp when the volume remains constant
P1/T1 = P2/T2 because an increase in temp increases the collision frequency and energy |
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combined gas law
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states the relationship among pressure, volume, and temp of a fixed amount of gas (constant). pressure is inversely proportional to volume and directly proportional to temp, and volume is directly proportional to temp
P1V1/T1 = P2V2/T2 |
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Avogadro's principle
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equal volumes of gases at the same temp and pressure contain equal numbers of particles
- the particles making up different gases vary in size, but they are usually far enough in size that they do not impact the total volume of gas |
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molar volume
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the volume that one mole occupies (at STP- 0.00 degrees C and 1.00 atm pressure)
* 1 MOLE OF ANY GAS WILL OCCUPY A VOLUME OF 22.4 L * (at STP) |
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impact of changing the number of moles
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a change in the number of moles will affect at least one of the other 3 variables
Ex: INCREASE in moles: - increase the pressure when volume and temp are constant OR - increase the volume when pressure and temp and constant |
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k
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PV/T = k
for a specific sample of gas, the relationship of pressure, volume, and temp is ALWAYS the same - where k is a constant based on the amount of gas present, n k = nR |
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ideal gas constant
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R
an experimentally determined constant - depends on the units used for pressure Ex: 8.314 L kPA/mol K |
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ideal gas law
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PV = nRT
describes the physical behavior of an ideal gas in terms of the p, v, t, and number of moles present no gas is truly ideal--under the right conditions of t and p, calculations made using the ideal gas law closely approximate what actually occurs |
