Final Summative
relevant variables
Researchers organize variables into a variety of categories, the most common of which include:
Independent variables. ...
Dependent variables. ...
Intervening variables. ...
Moderating variables. ...
Control variables. ...
Extraneous variables. ...
Quantitative variables. ...
Qualitative variables.
Quantitative data is data expressing a certain quantity, amount or range. Usually, there are measurement units associated with the data, e.g. metres, in the case of the height of a person. It makes sense to set boundary limits to such data, and it is also meaningful to apply arithmetic operations to the data.
tables are laballed and organized
Comprised of aqueous and gaseous solutions (solids and liquids don't participate)
A solution is a homogeneous (the same) mixture of two or more substances
A solute is a substance that is dissolved, usually present in smaller quantities
The solvent is the substance that does the dissolving, present in large quantities
Solutions consist of two parts: the solute(s) and the solvent
Quantifying solutions:
Solutions are classified based on their concentration
Concentration is a measure of how much solute is dissolved in the solvent (concentration = solute/solution
It is usually measured in molarity or mol dmˆ3 (decimeter cubed)
Higher values of molarity are considered concentrated (darker colors)
Lower values of morality are considered to dilute
(increasing solute means more concentrated, increasing more solvent means more dilute)
Equilibrium Reactions: (all chemical reactions are equilibrium reactions)
A system that is at equilibrium is a system where the forward reaction is occurring at the same rate as the occurring reaction (looks like nothing is changing).
All chemical reactions actually occur in both the forward and reverse directions.
Reactions that are written with an arrow only in one direction technically occurs in both reactions, but the reverse reaction is very slow and not visible
Equilibrium Reactions & Environmental Stress:
When an equilibrium reaction is exposed to environmental stress, it will shift to one direction in order to offset that stress.
When the equilibrium reaction shifts, it causes one side of the reaction to increase in concentration and the other to decrease.
Environmental Stress:
Environmental stress is anything that may alter the reaction rate between particles on one side of the reaction.
The most common stressors include:
Increasing or decreasing the concentration of a species in the reaction
Increasing or decreasing the temperature of a substance
Increasing or decreasing the pressure of a container (only for gases)
Environmental Stress - Concentration:
Increasing the concentration of a substance causes the reaction it is a "reactant" in to speed up.
Decreasing the concentration of a substance causes the reaction it is a "reactant" in to slow down.
When a reaction speeds up, we say the equilibrium shifts in that direction.
When a reaction slows down, we say the equilibrium shifts in the opposite direction.
Increasing the concentration can be done by adding the same compound or a compound with similar elements
Decreasing the concentration requires removing something from a substance, using the 2nd reaction:
Adding a base (-OH) to react with an acid (H-)
Adding a halogen to react with a cation
click to edit
f the concentration of C2H6 gas is increased
If the [ C2H6] is increased, the concentration of [C2H6] will decrease and the concentration [C2H4][H2] will increase as the equilibrium shifts to the right in order to balance the reactants and products.
if C2H6 is removed from the system
If C2H6 is removed from the system, the concentration of [C2H6] will increase and the concentration [C2H4][H2] will decrease as the equilibrium shifts to the left in order to balance the reactants and products.