Studied by 4 people
1 cal = ?J
4.184
System
The system includes the molecules we want to study
Surroundings
Everything else surrounding a system
First Law of Thermodynamics
Total energy of the universe is constant. If system loses energy, it must be gained by the surroundings and vice versa.
E°=?
Standard conditon
What happens to T of surrounding v system when energy is lost to surroundings
T of surrounding increases and T of the system decreases.
What happens to T of surrounding v system when energy is gained from surroundings
T of surrounding decreases and T of the system increases.
Exothermic
-Loss of energy
-Energy added to system
-Emitted energy
-Feels hot
-ΔH is negative
Endothermic
-Gain of energy
-Energy produced
-Absorbed energy
-Feels cold
-ΔH is positive
Energy + ΔH on the RIGHT side of equation is which type of process?
Exothermic reaction
Energy + ΔH on the LEFT side of equation is which type of process?
Endothermic reaction
Energy moves from ___ to ___
high to low
ΔH= ?
H products - H reactants
Extensive
Increase with amount
Enthalpy
the sum of a system's internal energy + product of its P and V
Enthalpy of fusion
Energy of phase change
Lattice energy
Energy to break ionic bond
Does the path of the reaction matter?
No, only the start and end are important
ΔH°f means…
Standard enthalpy of formation
ΔH°f of elements in their standard state equals?
0
ΔH°f O3 =
142.2 KJ/mol
Hess’s Law
If a reaction is carried out in a series of steps, ΔH for the overall reaction will be equal to the sum of the enthalpy changes for the individual steps.
What does enthalpy of solution depend on?
Enthalpy of hydration and enthalpy of lattice energy.
Colligative proprties
Higher the i value the higher the Bp and the lower the Fp.
Lattice energy
Amount of energy needed to break an ionic bond.
Transcriptions (ctriated complex)
When the bonds start to break in the reactants
When two bonds come together, is that endo or exo?
Exo
When a bond breaks is it endo or exo?
Endo
Heat Capacity
Energy needed to increase the temperature of a substance by one degree
Specific Heat (Specific Heat Capacity)
Energy needed to increase temperature of 1 gram substance
Molar Heat
Energy needed to increase temperature of 1 mole of substance
Extensive
Depends on the amount of substance
Intensive
Does not depend on the amount of the substance
Note 
Flashcard (83)