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34 Cards in this Set
- Front
- Back
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What is the kinetic theory of gases? |
a theory that seeks to explain the similarities observed in the behaviour of gases, based on the movement of particles that compose them. |
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Particles attract or repel each other, and that force depends on _____________________________ |
the distance between the particles. |
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What are the 3 ways of particle motion (explain)? |
1) vibration - symmetrical stretching, asymmetrical stretching and bending. 2) rotation - a particle turns on its axes (x, y and z). 3) translation - movement of particles in straight lines, from one collision to the next. |
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What is the formula for kinetic energy? |
Ek = 1/2mv^2 |
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What part of particles has the energy impact? |
the velocity. |
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What has a greater effect over the kinetic energy, the velocity or the mass? |
the velocity. |
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Why isn't it appropriate to consider mean velocity to determine the mean kinetic energy of gas? |
Because in a sample of gas, not all particles have the same kinetic energy, therefore they do not all have the same velocity. |
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What happens every time particles collide? |
There is a transfer if kinetic energy. |
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When you change the __________, there is a change in velocity. |
temperature. |
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At what temperatures are there more particles, and how does this have to do with their velocity? |
At higher temperatures, there are more particles, and these particles move faster at higher temperatures. |
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What 3 elements have to do with the movement of particles? |
1) heat 2) energy 3) temperature |
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What is hypothesis 1 of the kinetic theory of gases? |
the particles of a gas are infinetly small, and the size of the particle i negligible compared to the volume of the contained that holds the gas. |
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What is hypothesis 2 of the kinetic theory of gases? |
the particles of a gas are in constant motion and move in a straight line in all directions. They are colliding, creating energy. |
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What is hypothesis 3 of the kinetic theory of gases? |
the particles of gas do not exert any force of attracting or repulsion on each other. |
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What is hypothesis 4 of the kinetic theory of gases? |
the mean kinetic energy of gas is directly proportional to the absolute temperature (the peak of the graph-the mean). |
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What is absolute zero? |
when everything in motion hits zero heat and/or energy (-270 degrees Celsius). |
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What is compressibility? |
-supported by hypothesis 1. -due to large inter-particle distance, gases can be stored in small places under high pressure. |
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What is expansion? |
-supported by hypothesis 2. -gas dilate indefinetly by filling any accessible space. Great dilation leads to greater inter-particle distance. Expansion varies directly with atmospheric pressure. |
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What is diffusion? |
-supported by hypothesis 2. -the random dispersion of aimless colliding particles. -movement from a concentrated area to a less concentrated area. |
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Why don't all gases diffuse at the same rate? |
because the rate depends on the velocity of the particle. Therefore, at there same temperature, a particle with a smaller mass will move more quickly than larger ones. |
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What is effusion? |
-supported by hypothesis 2. -when a gas flows across a barrier through a small opening. -particles with smaller radii defuse more easily through the membrane. |
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What is the formula of diffusion and effusion of 2 different gases at the same temperature and pressure? Which hypothesis is this supported by? What is this law called? |
-supported by hypothesis 4. - V1/V2 = √m2/m1 -this is called Graham's law. |
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What is pressure of gases? |
-supported by hypotheses 2 and 4. -the pressure of gas corresponds to the force they exert on a surface. - P=F/A -from hypothesis 4, the mean kinetic energy from the particles of 2 gases is the same, therefore a light gas will collide more frequently than a heavier one. |
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How is atmospheric pressure measured, who invented this device and in what year? |
-measured using a barometer -created by Torricelli in 1643. |
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101.3kPa = ________ = _________ |
101.3kPa = 760mm Hg = 1atm |
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How is gas pressure measured? |
By using a manometer or a pressure guage. |
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What are the 2 types of U-tube manometers (explain)? |
1) closed end: -real pressure of the gas -Pgas = height of column 2) open end: -Pgas > Patm --> Pgas = Patm + h -Pgas < Patm --> Pgas = Patm - h |
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What are the 4 variables that describe gases? |
1) pressure 2) volume 3) absolute temperature 4) quantity of gas (number of moles) |
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What are the 3 evolving gas laws? |
1) simple - P1V1/P2V2 --> V1/T1 = V2/T2 2) ideal - PV = nRT 3) general - P1V1/n1T1 = P2V2/n2T2 |
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What is Boyle's law (explain)? |
-P1V1 = P2V2 -at a constant temperature, the volume occupied by a given gas is inversely proportional to the pressure of the gas.
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V oc 1/P = ___________ or ____________. What does this express? |
-V = k^a -PV = k^a -this introduced the proportionality constant. -This permits us to create a simple equation. |
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What is the proportionality constant? |
-PV = constant -m = y/x = 400kPa/2L^-1 = 200kPa-L |
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If calculate the slope of the line, that is the value for the __________. |
Constant. |
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For any co-ordinates, ___________ and ____________ are true. |
P1V1 = K^a P2V2 = K^a |
