Final Exam Flashcards
Define exothermic vs. endothermic :
Exothermic- releases heat
Endothermic- requires heat
Define rate reaction:
The rate at which products are produced. Expressed as unit/time.
What is the collision theory ?
The idea that particles must physically collide in order for a chemical reaction to occur.
What does a catalyst do in a chemical reaction? A inhibitor?
Catalyst- speeds up the reaction by reducing the amount of activation energy required
Inhibitor- slows down a chemical reaction
What is a reaction mechanism?
A specific series of steps to illustrate exactly how a chemical reaction will work
How can particle size affect the rate of reaction?
If particles are smaller they collide more and can move around more resulting in frequent collision making the reaction happen faster
How does temperature affect the reaction rate?
Higher the temperature , the faster the reaction
Lower the temperature , slower the reaction
How does the container size affect the rate of reaction?
Smaller the container, the more collisions speeding up the reaction
Bigger the container, the less amount of reactions slowing down the reaction
Define equilibrium in a chemical reaction:
When the forward and reverse reaction rates are equal
What is the law of equilibrium?
For every chemical reaction at equilibrium, there exists a ration between the products and reactants that will be a constant value at a given temperature.
How does the value of an equilibrium constant show whether the reaction favours the products or reactants?
The larger the value, the more products
Keq>1 favours the products
Keq< 1 favours reactants
Which states of matter are excluded from an equilibrium constant expression?
Solids and liquids
What is LeChatelier’s principle?
States that if a stress is placed on a system it will shifts to offset the stress
Define the Arrhenius theory of acids and bases?
All acids must contain H and all bases must contain OH-
State the bronsted-Lowry theory of acids and bases?
All acids donate H and all bases accept H.
List 5 strong acids.
HCL H2SO4 HNO4 HI HBr
List 5 string bases.
NaOH LiOH KO Ca(OH)2 Ba(OH)2
Give the 3 pH scale “rules” in terms of acid,base and neutral?
PH 7 base
PH=7 neutral
Distinguish in terms of number of ions dissociated, the difference between a strong and weak acid or base.
Strong acids and bases are 100% dissociated which means the whole compound dissociates into positive and negative ions. Weak ones on the other hand remain as molecules with very few ions dissociating.
Define polypropylene acid:
How many hydrogens are available to be ionized. They will only ionize at one time.
Define mono, di and triprotic:
Mono- has 1 H
Di- has 2H
Tri- has 3 H
What is the KW expression for self ionization for water?
H2O + H2O ——-> H + OH-
What does it mean in terms of Kw for a solution to have a pH of 7?
It means that H3O = OH- in the solution
Define oxidation and reduction:
Oxidation - loss of electrons
Reduction- gain of electrons
What is the function of an anode and cathode?
Anode- site of oxidation
Cathode site of reduction
What is the function of the salt bridge ?
Io ice solutions fills the tube which allows the positive and negative ions to pass through to keep the cell overall neutral.
What is meant by the ground state of an element ?
This is the location of all electrons in an element at its most minimum energy state
What are the 4 orbital shapes called ? What are the general shapes of them ?
S- circular
P- dumbbell
D- flower shapes
F- varying shapes
How many electrons can each orbital hold?
2 electrons per lobe
Name and describe the three rules that determine how electrons will be arranged in orbitals.
Hunds principle- each orbital in a shell must contain one electron before a second electron will fill any lobe
Pauli exclusion principle- each lobe of an orbital can hold up to two electrons
Aufbau principle - electrons will be added to the orbitals beginning at the lowest available energy
Define principle quantum number:
The principle quantum number of an element describes the size of the orbit of that particular element
Define ionization energy:
The amount of energy it takes to remove an electron from the valence she’ll of an electron
Describe the trend in atomic radii on the periodic table.
The size of an atom gets smaller as you go from left to right across a period (row). This is due to more concentration nucleus holding on to electrons while the outer most orbit doesn’t actually get a whole lot larger. It gets larger as you go down a group (column). This is because there are more orbitals and they are just physically larger
