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Forms of energy
Thermal Energy, Chemical Energy
2 main TYPES of energy
Potential Energy (stored energy) and Kinetic Energy (energy of motion)
Examples of Potential Energy
Nuclear, Gravitational, chemical
Examples of Kinetic Energy
Light, Thermal, sound waves, electic
The Law of Conservation of Energy (1st Law of Thermodynamics)
Energy cannot be created or destroyed, only transformed from one form to another.
Chemical Potential Energy
is the energy stored in the bonds of chemical compounds, such as molecules and atoms, and is released or absorbed during a chemical reaction.
Thermal Energy
The amount of energy from moving atoms in a substance (heat)
Units of Energy
Energy is measured in Joules
Temperature is
Kinetic energy
Units of Temparture
Celcius (based on water)
Kelvin (based on absolute zero = No Kinetic energy at all)
0k= -273 C
Heat flows
Heat is ALWAYS Transferred from Hot to Cold
Calculating Heat
Q= c ・ m ・ ΔT
Calculating Temperature Change
ΔT = Tfinal - TInitial
Types of Heat Reactions
Exothermic: Releasing into surroundings
Endothermic: Surrounding to system
Specific Heat
The amount of energy required to change the temperature of 1 gram of a substance by 1o celsius
Enthalpy
measure of the total heat content of a system Enthalpy
Delta H (positive for___ negative for ___)
Positive for Endothermic reactions, negative for exothermic reactions.
Hess’s Law
States that the total enthalpy change during a chemical reaction is the same, regardless of the pathway taken.
Enthalpy
is a state Function: a value that depends on only the initial and final state of the system
Spontaneous vs Non Spontaneous
Spontaneous processes occur without external intervention (automatically at given set of conditions)
Non-spontaneous processes require energy input to proceed (Activation Energy)
Just know this….
Either way, the Activation Energy is higher than both
Catalysts
(speeds up reactions via lowering activation energy) A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change
A Catalyst is a (product or reactant)
It’s neither idiot… We know this because there is the same amount of it before and after the reaction
Entropy
the natural tendency of the components of the universe to become disordered/disorganized/spread out/more chaotic
2nd Law of Thermodynamics
states that the entropy of the universe is always increasing
(reverse entropy)
If we use expendable energy in order to reverse the effects of entropy… we are also increasing the entropy of that energy
reversible reaction
a reaction in which the conversion of reactants to products and the conversion of products to reactants occur simultaneously.
Rewriting a reversible reactionss
with arrows in both directions to indicate the movement goes both ways
equilibrium
When a system has a reaction and reverse reaction occurring so that at any point there is a constant amount of reactants and products
equilibrium is equal?
This DOES NOT MEAN that the reactants and products are equal…just that the rate they are being formed is Equal
