Chapter 13.1 And 14 Vocab and Key Concepts Flashcards
Kinetic theory
All matter consists of tiny particles that are in constant motion
Kinetic energy
The energy an object has because of it’s motion
Gas pressure
Results from the force exerted by a gas per unit surface area of an object
Vacuum
An empty space with no particles and no pressure
Atmospheric pressure
Results from the collisions of atoms and molecules in air with objects
Barometer
A device that is used to measure atmospheric pressure
Pascal (Pa)
The SI unit of pressure
Standard atmosphere (atm)
The pressure required to support 760mm of mercury in a mercury barometer at 25degreesC
What is the numerical relationship converting atm?
1 atm = 760 mm Hg = 101.3 kPa
Briefly describe the assumptions of kinetic theory as applied to gases.
- The particles in a gas are considered to be small, hard spheres with an insignificant volume
- The motion of the particles in a gas is rapid, constant, and random
- All collisions between particles in a gas are perfectly elastic
Use kinetic theory to explain what causes gas pressure.
Gas pressure is the result of simultaneous collisions of billions of rapidly moving particles in a gas with an object
How is Kelvin temperature of a substance related to the average kinetic energy of its particles?
The Kelvin temperature of a substance is directly proportional to the average kinetic energy of the particles of the substance
Compressibility
A measure of how much the volume of matter decreases under pressure
Ideal gas constant
(R) has the value 8.31 (L•kPa)/(K•mol)
Ideal gas law
The gas law that includes all 4 variables - P, V, T, and n
Equation: PV=nRT
Partial pressure
The contribution each gas in a mixture makes to the total pressure is called this exerted by that gas
Dalton’s law of partial pressures
States that, at constant volume and temperature, the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the component gases.
Diffusion
The tendency of molecules to move toward areas of lower concentration until the concentration is uniform throughout
Effusion
A gas escapes through a tiny hole in its container
Why is a gas easy to compress?
The space between the particles in a gas
List three factors that can affect gas pressure.
The amount of gas, volume, and temperature
How are the pressure and volume of a gas related at a constant temperature?
If the temperature is constant, as the pressure of a gas increases, the volume decreases
If pressure is constant, how does a change in temperature affect the volume of a gas?
If pressure is constant, as the temperature of an enclosed gas increases, the volume increases
What is the relationship between the temperature and pressure of a contained gas at constant volume?
As the temperature of an enclosed gas increases, the pressure increases, if the volume is constant
In what situations is the combined gas law useful?
It allows you to do calculations for situations in which only the amount of gas is constant
What do you need to calculate the amount of gas in a sample at given conditions of temperature, pressure, and volume?
To calculate the number of moles of a contained gas requires an expression that contains the variable n
Under what conditions do real gases deviate most from ideal behavior?
At low temperatures and high pressures
In a mixture of gases, how is the total pressure determined?
It is the sum of the partial pressures of the gases
What is the effect of molar mass on rates of diffusion and effusion?
Gases of a lower mass diffuse an effuse faster than gases of higher molar mass
Equation for ideal gas law
PV=nRT
Equation converting Celsius to kelvin
K= degrees C + 273
Equation for circumference
C=2pi r
Equation for volume
V= 4/3 pi r^3
Conversion between mili- and normal
1000mm=1m
Conversion from normal to kilo-
1000m=1km
Equation for Dalton’s law of partial pressures
P total = P1 + P2 + P3 + …..
