Gases Flashcards
What are the chemical properties of gases?
Gases are either very reactive, slightly reactive, or not reactive
What are the physical properties of gases?
Regardless of chemical properties all gases:
- always fill their container and have no definite shape or volume
- are highly compressible
- diffuse through any available space
- have volume and/or pressure affected by temperature
What is atmospheric pressure?
The pressure exerted by air on all objects
Standard Temperature and Pressure (STP) = 101.325 kPa and 0 C
Laboratory temperatures are not at 0 degrees so scientists agreed on another set of conditions
Standard Ambient Temperature and Pressure (SATP) = 100 kPa and 25 C
What is temperature?
The average kinetic energy of the particles of a substance
What is the formula to convert Celsius to Kelvin
K = C + 273
What is the Kinetic Molecular Theory?
The smallest entities of a substance are in continuous motion
As they move about these molecules collide with each other and with objects in their path
According to the theory the motion of molecules is different in solids, liquid, and gases
What is Avogadro’s Theory?
Equal volumes of gases at the same temperature and pressure contain equal numbers of molecules
This means the mole ratios provided by a balanced equation are also the volume ratios
What is Boyle’s Law?
Considers the effects of pressure on the volume of a gas only while temperature is held constant
This is an inverse relationship
States: as the pressure on a gas increases, the volume of the gas decreases proportionally if temperature and mass are constant
P1V1 = P2V2
What is Charles’ Law?
Shows the relationship between temperature and volume of a gas if pressure is constant
This is a direct relationship
States: as the temperature of a gas increases, the volume increases proportionally, provided that the pressure and mass remain constant
V1/T1 = V2/T2
What is the Combined Gas Law?
When Boyle’s and Charles’ Laws are combined, the resulting combined gas law produces a relationship among the volume, temperature and pressure of any fixed mass of gas
What is ideal gas?
Does not really exist, it is hypothetical
Follows all gas laws perfectly under all conditions
Does not condense when cooled
Assumes that the particles have no volume and are not attracted to each other
What is real gas?
Does not follow gas laws exactly
It deviates at low temperatures and high pressures
Condensed to liquid of solid when cooled or under pressure
Particles are attracted to each other and have volume
Behaves like an ideal gas at higher temperatures and lower pressures
What is the Ideal Gas Law?
Describes the interrelationship of pressure, temperature, volume and amount (moles) of matter; the four variables that define a gas system
What is molar volume?
Is the same for all gases at the same temperature and pressure
STP = 22.4 L/mol SATP = 24.8 L/mol
