chemistry

• Physical states of matter

  Anything that has mass and occupies space
• Physical states of matter

  • Solid
  • Liquid
  • Gas
  • Plasma
• Changing physical states of matter

  Varying temperature and pressure
• Solid


  • Rigid
  • Particles have fixed volume and fixed shape
  • High density
  • Particles are close packed and highly organized
  • Particles vibrate at fixed points with respect to neighboring particles
• Liquid


  • Take the shape of the container
  • Have a definite volume
  • Slightly compressible
  • Ability to flow
  • Particles constantly shift their position
• Gas


  • No fixed shape or volume
  • Highly compressible
  • Particles constantly shift their position
• Plasma


  • Exists at high temperatures (even millions of degrees C)
  • Particles have electric charge and are affected by electric fields
• Nitrogen and oxygen can exist as solid, liquid and gas
• Nitrogen and oxygen have many applications
• Robert Boyle performed the first quantitative experiments on the property of gases
• Boyle concluded that at constant temperature, the pressure of a gas is inversely proportional to its volume
• Boyle's law


  At constant temperature, the pressure of a gas is inversely proportional to its volume
• Boyle's law


  1. Pressure and volume are inversely related

  2. Product of pressure and volume is constant (P1V1 = P2V2)

  3. Applies at constant temperature and mass/moles
• Boyle's equation: PV = K, where K is a proportionality constant
• The product of pressure and volume is always constant (P1V1 = P2V2)
• As the pressure of a gas increases, its volume decreases at fixed temperature and mass/moles
• Sulfur dioxide that forms acid rain is found in exhaust of petrol and diesel vehicles and power plants
• Boyle's law examples


  • 1.5 L sample at 5.6 kPa, pressure changes to 50 kPa, find new volume
  • Gas occupies 10 m^3 at 100 kPa, find new pressure if volume increases to 20 m^3
  • Cylinder with 4 atm pressure and 6 L volume, find new volume if pressure decreases to 1 atm
• Charles was the first person to fill a balloon with hydrogen gas and made the first balloon flight
• Charles' law

  At constant pressure, the volume of a gas is directly proportional to its absolute temperature
• The volume of a gas extrapolates to zero at absolute zero (-273.15°C)
• Temperature is a measure of the average energy of gas molecules
• Proportionality constant (K) in Charles' law


  Depends on the quantity of gas and pressure
• Using Charles' law

  1. V1/T1 = V2/T2

  2. Convert temperatures to Kelvin

  3. Solve for unknown volume or temperature
• Charles' law examples


  • Gas at 50°C and 1 atm has 2.58 L volume, find new volume at 38°C and 1 atm
  • Gas has 2.8 L volume at unknown temperature, decreases to 2.57 L in ice water at 0°C, find initial temperature
• At constant pressure, the volume of a gas changes by a fraction proportional to the change in absolute temperature
• The volume of a gas will be half its original volume at a temperature 1/3 of the original absolute temperature
• Charles' law examples

  • Gas at 25°C and 1 atm has 1.5 dm^3 volume, find new volume at 100°C and 1 atm
• Gay lussac's law

  pressure is Directly proportional to temperature at constant volume
• Pressure


  Directly proportional to temperature at constant mass
• As pressure increases, temperature also increases directly
• Pressure of a fixed amount of gas

  Varies directly with temperature at constant volume
• Pressure divided by temperature is always constant (K)
• Pressure increases


  Temperature increases directly by the same factor
• This equation compares different conditions on the same substance
• Pressure of a gas is directly proportional to temperature at constant volume
• Calculating pressure P2 when temperature T2 is known

  P2 = (T2 * P1) / T1
• Calculating initial temperature T1

  T1 = (P1 * T2) / P2
• Volume is directly proportional to temperature and inversely proportional to pressure
• Calculating temperature T2 using combined gas law

  T2 = (T1 * P2 * V2) / (P1 * V1)