States of matter Flashcards
Gas particles
- are far apart
- cannot be compressed
- are randomly arranged
- can move freely from place to place, in all directions
Liquid particles
- are closed together
- fixed volume
- can be slightly compressed
- randomly arranged
- have limited movement in all directions
Solid particles
- are touching each other
- cannot be compressed
- regular arrangement
- vibrate in fixed positions
4 types of structure
- Simple molecular/atomic
- Giant Ionic
- Giant Molecular
- Metallic
Simple molecular ex
- CO2
- Argon
Giant ionic ex
- NaCl
Giant molecular ex
- Silicon ( IV ) oxide
Giant metallic ex
- iron
- copper
Kinetic theory of gases
- gases and liquids are in constant movement
- can be used to explain the effect of temperature & pressure on volume of a gas & rates of chemical reactions
Ideal gas
a gas whose volume varies in proportion to the temperature and in inverse proportion to the pressure
Real gas
a gas that doesn’t obey ideal gas law, especially at low temperatures and high pressures
The volume that a gas occupies depends on :
- pressure
- temperature
The assumptions of ideal gases are :
- molecules are in constant random motion in straight lines
- molecules are rigid spheres
- pressure is due to molecules colliding to the walls of the container
- all collisions are elastic
- temperature is proportional to the average kinetic energy of the molecules
Temperature in ideal gas behaviour
must be high enough above the boiling point so that there are no intermolecular forces between molecules
Pressure in ideal gas behaviour
must be low enough so that the volume of the individual molecules is negligible relative to the volume of the container
Ideal gas equation
pV = nRT
How do real gases deviate from ideal behavior?
Real gases deviate from ideal behavior at low temperatures and high pressures because:
- Intermolecular forces become significant, causing particles to attract each other.
- The volume of gas particles is no longer negligible compared to the container volume.
Freezing
Liquid to solid (releases energy, exothermic).
Melting
Solid to liquid (requires energy, endothermic).
Evaporation / Boiling
Liquid to gas (requires energy, endothermic)
Condensation
Gas to liquid (releases energy, exothermic).
Sublimation
Solid to gas without becoming liquid (requires energy, endothermic).
What does Boyle’s Law state about the relationship between pressure and volume?
Boyle’s Law states that the pressure of a given mass of gas is inversely proportional to its volume at a constant temperature
What does Charles’s Law state about the relationship between volume and temperature?
Charles’s Law states that the volume of a given mass of gas is directly proportional to its temperature (in Kelvin) at constant pressure
What does Avogadro’s Law state about the relationship between volume and the number of moles of gas?
Avogadro’s Law states that the volume of a gas at constant temperature and pressure is directly proportional to the number of moles of gas
What is Dalton’s Law of Partial Pressures?
Dalton’s Law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each individual gas
