Gas Law

• Gas Law- show the relationship of pressure, temperature, volume and amount of gas
• Gas Law Cheat Sheet

  
• Boyle's Law

  ✓ tells us that the volume of gas increases as the pressure decreases.

  
• Charles' Law

  ✓ tells us that the volume of gas increases as the temperature increases.

  
• Gay Lussac's Law

  ✓ states that the pressure of a given amount of gas held at constant volume is directly proportional to the Kelvin temperature.

  
• Avogadro's Law

  ✓ tells us that the volume of gas increases as the amount of gas increases.

  
• Standard temperature and pressure (STP)

  ✓ reference conditions that people commonly use in the field of chemistry to compare the properties of gases.

  ✓ These conditions are defined as a temperature of 0 degrees Celsius (273.15 Kelvin) and a pressure of 1 atmosphere (760 mmhg or 101.325 kilopascals)

  
  

  P1V1/T1=P2V2/T2

  
• Dalton’s Law of Partial Pressure

  
• Ideal Gas

  ✓ is the theoretical substance that helps establish the relationship of four gas variables, pressure (P), volume(V), the amount of gas (n) and temperature(T). It has characters described as follow:

  o The particles in the gas are extremely small, so the gas does not occupy any spaces.

  o The ideal gas has constant, random and straight-line motion.

  o No forces between the particles of the gas. Particles only collide elastically with each other and with

  the walls of the container.
• Real Gas

  ✓ has real volume and the collision of the particles is not elastic, because there are attractive forces between particles.

  ✓ As a result, the volume of real gas is much larger than of the ideal gas, and the pressure of real gas is lower

  than of ideal gas. All real gases tend to perform ideal gas behavior at low pressure and relatively high temperature.

  The compressibility factor (Z) tells us how much the real gases differ from ideal gas behavior.

  Z = PV/nRT

  For real gases, Z≠1

  For ideal gases, Z=1
• Ideal Gas Law PV = nRT

  P = Pressure (atm)

  V = Volume (L)

  n = moles

  R = gas constant = 0.0821 atm•L/mol•K

  T = Temperature (Kelvin)
• What does Boyle's law relate to?- Volume and Pressure
• If you increase the pressure of a constant volume of gas, what will happen to the temperature?- increase
• What law combines all 3 factors (pressure, temperature, and volume)- combined gas law
• With pressure, volume, and temperature being known values, the ideal gas law can be used to — calculate the number of moles
• In Charles' Law, volume and temperature are _________ proportional.- directly
• What is the volume of 1 mole of gas at Standard Temperature and Pressure (STP)?- 22.4 L (1mol- 22.4L)
• Indicate what the missing words are in the following statement of Charles’ law: At constant pressure, the volume of a gas sample is _______ proportional to its _______ temperature. -directly; Kelvin
• If the temperature of any gas is increased its volume _______ (assuming pressure stays the same).- increases
• Which of the following is NOT a unit of pressure?- mL
• Which of the following best describes Charles' Law?- Direct relationship between volume & temperature
• What variable is held constant with Boyle's Law?- temperature
• An inflated balloon is placed in a refrigerator. The volume will __________.- decrease
• Which of the following is an example of a direct relationship? -As one variable goes up, the other variable goes up also.
• How do you use the combined gas law to solve any gas law problem?- You ignore the parts of the equation that you're not given, unless you're given all three
• If a hairspray can is heated, what can be expected of the pressure of the gas inside the can?- The pressure will increase
• In an experiment with the apparatus shown, the plunger is used to compress helium gas to different volumes. The corresponding volume and pressures (arbitrary units) are measured and displayed in the table below. Which statement best characterizes the data in the table above?- As the volume decreases, the pressure increases.
• Three gases are mixed together in a container with a total pressure of 4.8 atm. If two of the gases have pressures of 1.2 atm and 1.5 atm, what is the pressure of the third gas? -2.1 atm
• A student measures the pressure and volume of an empty water bottle to be 1.4 atm and 2.3 L. She then decreases the pressure to 0.65 atm. What is the new volume?- 5.0L
• A sample of gas with a volume of 30.0 mL at 25.0°C is heated to 50.0°C. What is the new volume of the gas?- 32.5 mL
• What is the pressure of a car tire that had an initial pressure of 1.8 atm but was heated from 38°C to 123°C?- 2.3 atm
• Determine the number of moles in a container of gas at STP with a volume of 99.2 L.- 4.43 moles
• Determine the Kelvin temperature required for 0.0470 mol of gas to fill a balloon to 1.20 L under .998 atm pressure.- 310K
• R(gas constant)= 0.0821
• kelvin= 0 degrees celcius + 273.15