Section 5 : Solids, Liquids and Gases

• Pressure (Pa) = Force (N)/Area ($m^2$)
• Pressure (Pa) = hpg

  in liquids
• Density = mass/volume
• Density = number of particles packed closely together in an object or substance
• Pressure = effect of a force on an area
• Factors affecting gas pressure

  
  

  • Heat
  • Concentration
• Heat

  • More heat -> More KE -> More frequently particles colliding -> High Pressure
  • Less heat -> Less KE -> Less frequently particles colliding -> Less Pressure
• Concentration :

  
  

  • High conc. -> More frequent particles colliding -> High Pressure
  • Low conc. -> Less frequent particles colliding -> Low Pressure
• Absolute Zero = -273 °C (0 K)
• °C to K = Temp in °C + 273

  K to °C = Temp in K - 273
• Temperature Law states that the pressure of a gas is directly proportional to the Kelvin temperature if the volume remains constant
• P1/T1 = P2/T2
• Direct Proportion : y = kx
• Inverse Proportion : y ∝ 1/x
• Volume Decreases -> Particles hit the container more frequently -> increase the pressure
• Volume Increases -> Particles hit the container less frequently -> decrease the pressure
• Gas at same temperature = avg. particle speed remains the same
• Heat energy breaks bonds/attractions to make particles move apart
• Latent Heat = Energy used to change state of 1 kg of substance with no temperature change.
• Latent Heat formula :

  (J/kg) L = Energy (Joules)/mass (kg)
• Specific Heat Capacity : amount of energy needed to increase temperature of the atoms of a substance by 1 C per kg.
• SHC = Energy x mass x change in temp