Gases Flashcards Preview

CHER3S > Gases > Flashcards

Flashcards in Gases Deck (16):

Define KMT

Kinetic Molecular Theory
attempts to explain the behaviour of particles in all 3 states of matter


Name the 6 principal assumptions of the KMT

-gas consists of tiny particles
-the volume occupied y gas is consist mostly of empty space
-gas particles have no attraction for one another
-gas particles move in straight lines in one direction
-no energy is lost in a collision of gas particles with themselves and the wall of the containers (elastic)
-average kinetic energy for particles is the same for all gases at the same temperature


Describe the barometer

-invented by Torricelli
-consist of a dish of mercury and a tube of mercury
-amount of mercury remaining in the tube is controlled by the amount of atmospheric pressure acting on the surface of the mercury in the dish


Charles' Law

-states that at a constant pressure the volume of a gasis directly proportional to the kelvin temp.
-studies have shown that is a gas is raised from 0 degrees Celsius to 273 degrees Celsius, its volume doubles
-V1/T1 = V2/T2


Gas Laws- Boyle's Law

this law states that at constant temp. the volume of a gas is inversely proportional to the pressure
P1V1 = P2V2


Concept of an Ideal Gas

-any gas that obeys all aspects of the KMT
-in reality, there is no such thing, we have real gases however, under certain conditions (low pressure and high temp.) , a real gas could closely approximate an ideal gas


Ideal gas equation

PV = nRT
P- pressure
V- volume
n- moles
R- universal gas constant (0.0821 L atm / mol K) or (8.31 L kPa / mol K)
T- temp.


Describe Dalton's Law on Partial Pressure

-this law states that in a mixture on gases, each gas exerts a pressure as though it was the only gas in the container. The total pressure for the mixture is the sum of the individual partial pressure
P= nRT/V for each gas then add
OR Ptotal= ntotal RT / V


What are the colligative properties

1) vapour pressure- pressure exerted by a vapour in equilibrium with its liquid
2) boiling point- temperature at which vapour pressure is equal to atm
3) freezing point- temperature at which vapour pressure of a liquid is equal to the vapour pressure of a solid
4) osmotic pressure- the pressure required to stop osmosis


Describe osmosis

-movement of a solution from a region of high pressure to a region of low pressure
-OP (pi) = M R T i


Define a solution

a homogeneous mixture of two or more pure substances
-made up of a solute and a solvent


Describe solute and solvent

solute is the substance being dissolved or diluted and the solvent in the one that's doing the dissolving


What is the tyndall effect

-a method used to determine if a mixture is a solution or not. By passing a light through the mixture, its a solution if the beam goes straight through, and its not a solution if the beam is scattered


Name the qualitative categories

dilute solution- has lots of solvent and very little solute
concentrated solution- has lots of solute very little solvent
unsaturated solution- has less than the maximum amount of solute dissolved in a given quantity of solvent at a specific temp.
saturated solution- has the maximum amount of solute dissolve in a given quantity of solvent at a specific temp.
super saturated solution- has more than the maximum amount of solute in a given quantity of solvent at a specific temp.


Define and Name the quantitative terms

these give an exact numeric value for the concentration
% by mass
% by volume
parts per million (ppm)
parts per billion (ppb)


Desc. Molarity

the abbreviation is molar
the symbol is "M"
by definition molarity refers to the moles of solute per dm^3