GAS LAWS

• hello students today is the start of the fourth quarter of grade 10 science for those who are new in this channel i am mom deya and i am your science teacher for today today's discussion we will be talking about the behavior of gases particularly about boyle's law and charles law
• before we proceed let's have a review of the different states of matter when you were in the elementary levels you studied solids liquids and gases
• Solids


  • More compact in nature
• Liquids


  • Particles slightly far apart compared to solids, take the shape of their container
• Gases


  • Particles very far apart, take up all the space in the container
• our focus this quarter is all about gases
• Properties of gases


  • Pressure (P)
  • Volume (V)
  • Temperature (T)
  • Amount (n)
• Pressure


  Force acting on a specific area
• Units of pressure


  • atm (atmosphere)
  • mmHg (millimeter mercury)
  • Torr
  • psi (pounds per square inch)
  • kPa (kilopascals)
• in our study for most of this quarter we will be using atmospheres, millimeter mercury and Torr
• Volume


  Three-dimensional space occupied by a gas
• Units of volume


  • milliliters
  • liters
  • cubic meters
  • cubic centimeters
• Temperature


  Measure of the average kinetic energy of the particles in an object
• Temperature units


  • Fahrenheit
  • Celsius
  • Kelvin
• in our calculations we will be using Kelvin as the standard unit for temperature
• Quantity


  Measured in moles, one mole is equal to 6.022 x 10^23 units of a substance
• Boyle's law relates pressure and volume at constant temperature and amount of substance
• Boyle's law


  Pressure is inversely proportional to volume at constant temperature
• Volume increases


  Pressure decreases
• Volume decreases


  Pressure increases
• Boyle's law demonstration


  1. Put marshmallow in syringe

  2. Observe what happens when syringe is pushed and released
• Pushing the syringe decreases the volume and increases the pressure, releasing the syringe increases the volume and decreases the pressure
• Boyle's law formula


  P1 * V1 = P2 * V2
• Solving Boyle's law problem

  1. Identify given values (V1, P1, P2)

  2. Substitute into formula P1*V1 = P2*V2

  3. Solve for V2
• If pressure doubles, volume decreases by half. If pressure quadruples, volume decreases to one-fourth.
• Applications of Boyle's law

  • Syringe action
  • Chip bags at high altitude
  • Breathing (diaphragm movement)
• Charles law relates volume and temperature at constant pressure
• Charles law


  Volume and temperature are directly proportional
• Volume increases


  Temperature increases
• Volume decreases


  Temperature decreases
• Charles law formula


  V1/T1 = V2/T2 (temperatures must be in Kelvin)
• Solving Charles law problem

  1. Identify given values (V1, T1, T2)

  2. Substitute into formula V1/T1 = V2/T2

  3. Solve for V2
• Applications of Charles law

  • Hot air balloons
  • Ping pong balls
  • Baking (bread, pastries)