science

• kinetic molecular theory


  a model that helps us understand the physical properties of gases at the molecular level in ideal state.
• Kinetic


  refers to the motion of the molecules, which are constantly moving, flying about in all directions
• PROPERTIES OF GASES

  • Mass
  • Volume
  • Pressure
  • Temperature
• refers to the amount of matter in an object


  Mass
• refers to the space occupied by the matter


  Volume
• the measure of the coldness or hotness of a material.


  Temperature
• the force applied by the gas particles per unit area.


  Pressure
• explains the relationship between property of gases. It helps predict how gas will react if pressure, temperature, or volume is changed or kept constant.


  Gas Laws
• the first person to state the relationship between volume and pressure at constant temperature during the 16th century.


  Robert Boyle
• states that the volume of a gas is inversely proportional to its pressure at constant temperature


  Boyle's Law
• INVERSELY PROPORTIONAL - pressure increases, volume decreases / pressure decreases, volume increases
• The volume - temperature relationship in gases was determined by and named after


  Jacques Charles
• states that the volume of a gas is directly proportional to its temperature at constant pressure.


  Charles's Law
• DIRECTLY PROPORTIONAL - volume increases, temperature increases / volume decreases, temperature decreases
• one of the phases of matter. It has no definite shape and size. It can be compressed easily.


  GAS
• unit of pressure


  P
• unit of volume


  V
• unit of temperature


  T
• always use GRESA in problem solving, find the GIVEN, identify the REQUIRED, write the EQUATION and SOLVE, state your ANSWER in sentence form
• A 200 L of gas contained in a vessel under a pressure of 850 atm. What will be the new volume if the gas is changed to 1000 atm?

  170 L
• A scuba diver needs a diving tank to provide breathing gas while he is underwater. How much pressure is needed for 6.00 liters of gas at 1.01 atmospheric pressure to be compressed in a 3.00-liter cylinder?

  2.02 atm
• A sample of fluorine gas occupies a volume of 600 mL at 760 torr. Given that the temperature remains the same, calculate the pressure required to reduce its volume by 1/3.(to convert mililiters into Liters, divide the number by 1000).

  2,280 torr
• what is (°C + 273.15) *applicable only to temperatures in Celsius*?

  Kelvin
• A tank (not rigid) contains 2.3L of helium gas at 25°C. What will be the volume of the tank after heating it and its content to 40°C temperature at constant pressure?

  2.42 L
• At 20°C, the volume of chlorine gas is 15dm3. Compute the resulting volume if the temperature is adjusted to 318K provided that the pressure remains the same. (to convert cubic decimeter into liters, multiply the number by 1).

  16.27dm3
• Volume should ALWAYS be expressed/converted in L
• The principal assumptions of the kinetic molecular theory are:

  1. Gases are composed of molecules. The distances from one molecule to another molecule are far greater than the molecules’ dimensions. These molecules are so small that their mass and volume are considered to be insignificant.
• The principal assumptions of the kinetic molecular theory are:

  2. Gas molecules are always in constant random motion and they frequently collide with one another and with the walls of the container. Collisions among molecules are perfectly elastic, that is, energy may transfer from one molecule to molecule as the result of collision but the total energy of all the molecules in the system remains the same/constant.
• The principal assumptions of the kinetic molecular theory are:

  3. Attractive and repulsive forces between gas molecules are so weak that they are considered to be insignificant.
• The principal assumptions of the kinetic molecular theory are:

  4. The average kinetic energy of gas molecules is directly related to its temperature.
• The size of the molecules affects the total volume of the gas.

  FALSE
• The average kinetic energy of a molecule at a given temperature is constant.

  TRUE
• There are insignificant attractive or repulsive forces between molecules.

  TRUE
• Collisions between molecules are perfectly elastic, that is, no energy is gained nor lost during the collision.

  TRUE
• A gas consists of a collection of small particles traveling in straight line motion and obeying Newton’s Laws.

  FALSE
• hypothesized that the volume of a gas is directly related to the number moles when the pressure and temperature are not changed.

  Amedeo Avogadro
• States that the volume of gas is directly proportional to the number of moles when the pressure and temperature remains constant.


  Avogadro’s Law
• unit of the number of moles


  n
• PV = nRT

  ideal gas law
• universal gas constant (0.0821 L.atm/mol.K)

  R