Thermodynamics Flashcards
what happens to density when temperature drops?
density of solution will increase
density is mass/volume
when temperature drops, the container will contract but the mass will stay the same.
When an object’s density is less than the solution
the object will float
Avogadro’s Law
number of moles is proportional to volume
at constant T and P
Charlie’s Law
T proportional to V
at constant P
Boyle’s Law
P inversely proportional to V
at constant T
Gay-Lussac’s Law
P proportional to T
at constant V
Dalton’s Law of Partial Pressure
the partial pressures of the gasses add up to the total pressure
How does temperature affect the reaction rate?
increasing temperature will increase the reaction rate because molecules move quicker and collide more often with more energy at higher temperatures
temperature and activation energy
higher temperatures make molecules collide more and have more energy which helps overcome the activation energy
exothermic reactions
negative delta H
temperature of system and immediate surrounds increase as heat is released
endothermic reactions
positive delta H
temperature of system and immediate surroundings decrease as heat is pulled in
Hess law
overall enthalpy change delta H of a reaction is equal to the sum of the changes in enthalpy of each component
positive entropy
system is more random, less ordered
negative entropy
system is more ordered
ln(Keq) is positive
delta G is negative and reaction is spontaneous
Keq > 1
ln (Keq) is negative
delta G is positive and reaction is nonspontaneous
Keq < 1
ln (Keq) = 0
the system is at equilibrium
Keq = 1 –> ln (1) = 0
Le Chatelier’s Principle
any changes to a system that moves it away from equilibrium, such as addition of products or reactants, will cause it to adjust accordingly to come back to equilibrium
adding more reactants shifts to products, removing reactants shifts towards reactants
adding heat to an endothermic reaction
shifts the equilibrium towards the products
the opposite is true for exothermic reactions
higher vapor pressure
weaker intermolecular forces (easier to turn into gas); lower boiling point
takes less heat to reach point of boiling
lower vapor pressure
stronger intermolecular forces (harder to turn into gas); higher boiling point
the low pressure requires more heat to reach boiling
irreversible reaction
kinetic reaction
forms under low temperatures and moves quickly
the reactions with the lowest activation energy will form fastest and create the most product in a short amount of time
reversible reactions
thermodynamic reaction
forms at higher temperatures and moves slowly
whatever has the highest gibbs free energy will make the reaction most stable and will mean that the product is least likely to reversibly change –> therefore would have the most product
units of rate
M/s
moles/L*s
What will affect the equilibrium constant
only temperature
as temperature increases, the solubility product constant increases for non-gas solutes and decreases for gas solutes
