Test 1 Ch. 7-8 Flashcards
The study of energy, work, and heat
THERMODYNAMICS
molecules and atoms in a reaction mixture are in constant, random motion
KINETIC MOLECULAR THEORY
molecules and atoms frequently collide with each other
KINETIC MOLECULAR THEORY
Only some collision, those with sufficient energy, will break bonds in molecules.
KINETIC MOLECULAR THEORY
When reactants bonds are broken, new bonds are formed and products result
KINETIC MOLECULAR THEORY
System vs. surroundings = contains the process under study
SYSTEM
System vs. surroundings = the rest of the universe
SURROUNDINGS
Energy of the universe is constant
FIRST LAW OF THERMODYNAMICS
First law of thermodynamics aka
LAW OF CONSERVATION OF ENERGY
The energy required to break the bond is less than the energy released when the bonds are formed
EXOTHERMIC REACTION
The energy required to break the bond is greater than the energy released when the bonds are formed
ENDOTHERMIC REACTION
/\ H. represents heat energy
ENTHALPY
Change in enthalpy will be ____ in Exothermic reactions
NEGATIVE
Change in enthalpy will be ____ in Endothermic reactions
POSITIVE
Most, but not all, ______ reactions are spontaneous
EXOTHERMIC
Most, but not all, ______ reactions are nonspontaneous
ENDOTHERMIC
The universe spontaneously tends towards increasing disorder and randomness
SECOND LAW OF THERMODYNAMICS
Measure of randomness of a chemical system
ENTROPY
Highly disordered system the absence of a regular repeating pattern
HIGH ENTROPY
well organized system such as a crystalline structure
LOW ENTROPY
/\ G. represents the combined contribution of the enthalpy and entropy values for a chemical reaction
FREE ENERGY
negative /\ G
ALWAYS SPONTANEOUS
positive /\ G
NEVER SPONTANEOUS
/\ G = ….
/\ H - [ T (kevlin) * /\ S ]
The measurement of heat energy changes in a reaction
calorimetry
Q = Ms * /\ T * SHs
what do all values mean
- specific heat (SHs)
- change in temp (/\ T)
- Mass of the solutions
The number of calories of heat needed to raise the temp of 1g of the substance 1c
Q = Ms * /\ T * SHs
the study of the rate/speed of chemical reactions
KINETICS
the difference between the energy of the reactants and that of the activation complex
ACTIVATION ENERGY (Ea)
process that can occur in both direction
REVERSIBLE REACTION
the rate of forward process in a reversible reaction is exactly balanced by the rate of the reverse process
DYNAMIC EQUILIBRIUM
Keq = aA + bB <–> cC + dD
[A]^a [B]^b
Keq greater than 1 x 10 ^3
- at equilibrium mostly product present.
Keq less than 1 x 10^ -3
- at equilibrium mostly reactants present
Keq between 1 x 10^-3 and 1 x 10 ^ 3
- mixture contains sigificant concentration between both reactants and products
If a stress is placed on a system at equilibrium, the system will respond by alternating the equilibrium composition in such a way as to minimize the stress
LECHATELIERS PRINCIPLE
Increase reactants
SHIFT TO PRODUCTS
Increase products
SHIFT TO REACTION
Increase pressure
SHIFT TO SIDE WITH LESS MOLES
decrease pressure
SHIFT TO SIDE WITH MORE MOLES
increase temp in an exothermic reaction
SHIFT TO REACTANTS
decrease temp in an exothermic reaction
SHIFT TO PRODUCTS
molecular collision, activation energy, molecular orientation
COLLISION THEORY
Bronsted Lower Acid
Proton H+ Donator
Bronsted Lowery Base
Proton H+ Acceptor
a substance, when dissolved in water dissociated to produce hydrogen ions
Arrhenius Acid
a substance, when dissolved in H20, dissociates to produce Hydroxide ions
Arrhenius Base
A substance poessing both acid and base properties
Amphiprotic
When NH3 dissolves in water it has ___ properties, however it does not have ____ ions in it
BASIC, OH-
6 strong acids (NEED TO KNOW IN THIS CLASS) and charge
HCL
HBr
HI
HNO3 +1
H2SO4
HClO4 +3
2 weak acids (NEED TO KNOW IN THIS CLASS)
CH3COOH
H2CO3
acetic acid
CH3COOH
Carbonic acid
H2CO3
3 Strong bases
NaOH
KOH
Ba(OH)2
3 Weak bases
NH3
C5H5NH2
C6H5NH2
Nitric Acid
HNO3
Sulfuric Acid
H2SO4
HCLO4
Perchloric Acid
only a small percent dissociates
Weak acid/bases
Calculating the pH of a buffer solution
pH = pKa + log ( Cb / Acid )
pKa =
-log(Ka)
- gain of electrons
- gain of H2
- loss of O2
REDUCTION
High pKa
Low ACID STRENGTH
Low pKa
High ACID STRENGTH
electrochemical cell that converts stored chemical energy
VOLTAIC CELLS
Mg -> Mg 2+ + 2e-
OXIDATION HALF REACTION
Cl + 2e- –> 2Cl
REDUCTION HALF REACTION
uses electrical energy to cause non-spontaneous oxidation-reduction reactions to occur
ELECTROLYSIS
Fill in the blank question.
The spontaneity of a chemical reaction depends on the relative magnitude of the __ and ____ values
ENTHALPY, ENTROPY
Decomposition of a liquid to form gaseous molecules ____ in entropy
INCREASE
Separation of a gaseous mixture into individual components ___ in entropy
DECREASE
Vaporization –> ___ in entropy
INCREASE
Condensation –> ___ in entropy
DECREASE
/\ S > 0
process moves to a state of increased disorder
T or F: gases have a higher entropy than solids
TRUE
Products have a higher potential energy than reactants
ENDOTHERMIC
Chemical kinetics is the study of the _____ of chemical reactions and gives an indication of the _____ of a reaction.
RATE ; MECHANISM
