States of matter Flashcards
(25 cards)
2 conditions where real gases act like ideal gases and explain how
1) High temperatures
Particles are constantly moving and colliding with high speed
2) Low pressure so the particles are apart from reach other so it has negligible intermolecular forces
What do gases in a container exert?
Gases in a container exert a pressure as the gas molecules are constantly colliding with the wall of the container.
What happens when the volume of a container decreases at constant temperature?
The molecules are squashed together, resulting in more frequent collisions with the container wall.
What is the effect on gas pressure when the volume decreases at constant temperature?
The pressure of the gas increases.
How is volume related to pressure at constant temperature?
The volume is inversely proportional to the pressure.
What does a graph of volume plotted against 1/pressure represent?
A graph of the volume of gas plotted against 1/pressure gives a straight line.
What happens when the temperature of a gas increases at constant volume?
The molecules gain more kinetic energy and move faster, colliding with the container walls more frequently.
What is the effect on gas pressure when temperature increases at constant volume?
The pressure of the gas increases.
How is temperature related to pressure at constant volume?
The temperature is directly proportional to the pressure.
What does a graph of temperature plotted against pressure represent?
A graph of the temperature of gas plotted against pressure gives a straight line.
What does the kinetic theory of gases state?
Molecules in gases are constantly moving.
What are the assumptions of the kinetic theory of gases?
- Gas molecules are moving very fast and randomly.
- Molecules hardly have any volume.
- No intermolecular forces (no attraction or repulsion).
- No kinetic energy is lost during collisions (elastic collisions).
- Temperature is related to the average kinetic energy of molecules.
What are gases that follow the kinetic theory called?
Ideal gases.
What are real gases?
Gases that do not fit the ideal gas description exactly but may come very close.
What factors determine the volume of an ideal gas?
The volume that an ideal gas occupies depends on its pressure and its temperature.
What happens to gas particles when heated at constant pressure?
The particles gain more kinetic energy and undergo more frequent collisions with the container wall.
What must happen to maintain constant pressure when a gas is heated?
The molecules must get further apart, resulting in an increase in volume.
How is the volume of a gas related to temperature at constant pressure?
The volume is directly proportional to the temperature (at constant pressure).
Why do real gases deviate from ideal gas behaviour at very high pressures and low temperatures?
Real gases deviate from ideal gas behaviour due to gas molecules being much closer together, significant intermolecular forces, and the volume of the molecules being non-negligible.
What are the two key assumptions of the kinetic theory that break down for real gases?
- There are no intermolecular forces. 2. The volume of the gas molecules can be ignored.
How do intermolecular forces affect the pressure of real gases?
Attractive forces between molecules pull them slightly inward, causing them to hit the container walls with less force than expected, resulting in lower measured pressure.
How does the volume of gas particles affect the free volume available for movement?
Gas particles occupy space, so the actual free volume available for movement is less than predicted by the ideal gas law.
What is the ideal gas equation?
The ideal gas equation is pV = nRT.
What do the variables in the ideal gas equation represent?
p = pressure (Pa), V = volume (m3), n = number of moles of gas (mol), R = gas constant (8.31 J K-1 mol-1), T = temperature (K).
