# Kinetic Theory and Gases - Topic 5

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What are the particles like in a solid?
There are strong forces of attraction between the particles holding them close together in a fixed, regular arrangement.
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What are the particles like in a liquid?
There are weaker forces of attraction so the particles are close together but can move past each other and form irregular arrangements. They can move in random directions slowly.
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What are the particles like in a gas?
There are almost no forces of attraction so the particles have the most energy and are free to move in random directions at fast speeds.
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What does kinetic theory state?
The kinetic theory of gases describes a gas as a large number of small particles, all of which are in constant, random motion. The rapidly moving particles constantly collide with each other and with the walls of the container.
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What is absolute zero?
0 Kelvin or -273 Celsius
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How does absolute zero work?
If you cool a substance, you reduce the kinetic energy of the particle. At absolute zero, the particles have as little kinetic energy as possible.
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How do you convert from Celsius to Kelvin?
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How do you convert from Kelvin to Celsius?
Subtract 273
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What is the kelvin temperature of a gas proportional to?
The Kelvin temperature of a gas is directly proportional to the average kinetic energy of its particles.
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What does this proportionality mean?
The temperature (K) and kinetic energy of the particles are always equal. For example, if you double the temperature, the amount of kinetic energy doubles too.
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How is outward pressure created by a gas?
As the particles collide, they exert a force on each other and one the walls. The smashing of particles against a sealed container's walls creates an outward pressure.
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What does this pressure depend on?
How fast the particles are moving and how often they hit the walls.
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What is the relationship between volume and temperature when a gas has a constant pressure?
When a gas is at a CONSTANT PRESSURE, its volume is proportional to its temperature.
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What does this proportionality mean?
That when a gas is at a constant pressure, its volume and temperature remain equal. E.g. if you heat a gas, more KE is created causing the particles to move faster and expand, increasing the volume as well as temperature of the particles.
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What is the relationship between pressure and volume when a gas has constant temperature?
The pressure and volume are inversely proportional to each other when a gas has a constant temperature.
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What does inversely proportional mean?
It means that when volume goes up, pressure goes down and vice versa.
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How can this be explained?
When the temperature is constant, reducing the volume of a gas squishes the particles up, making them hit the container walls more often, so the pressure increases.
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How are gases used medically?
Oxygen and nitrogen are used to help patients breathe in operations. They are stored under pressure in canisters or bottles.
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What is flow rate?
Flow rate is the volume of gas per unit of time released from a bottle.
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Why are gases kept at high pressures in bottles?
High pressure storage allows a high flow rate to occur and more gas can fit into a smaller space (bigger pressure = decreased volume)
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What happens when the pressure outside and inside of the bottle is equal?
The flow rate becomes 0, and no more gas can come out of the bottle. so there is always some left within a bottle/canister.
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## Other cards in this set

### Card 2

#### Front

What are the particles like in a liquid?

#### Back

There are weaker forces of attraction so the particles are close together but can move past each other and form irregular arrangements. They can move in random directions slowly.

### Card 3

#### Front

What are the particles like in a gas?

### Card 4

#### Front

What does kinetic theory state?

### Card 5

#### Front

What is absolute zero?