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46 Cards in this Set
- Front
- Back
Gas-->Solid
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deposition
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Gas-->Liquid
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condensation
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Liquid-->Solid
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freezing
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Liquid-->Gas
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evaporation
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Solid-->Liquid
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melting
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Solid-->Gas
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sublimation
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Melting Point
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the temperature and pressure at which a solid becomes a liquid
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Boiling Point
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the temperature and pressure at which liquid and gas molecules are in equilibrium
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fusion
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transition between solid and liquid
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enthalpy (both formulas)
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q=mCpT
Q=nCT |
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gibbs energy formula
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determines spontinaeity of the reaction
G=H-TS |
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catalyst
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speeds up reaction
moves curve down on the graph that shows exothermicness |
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heat
vs temp |
heat: the energy transferred between objects that are at different temperatures
temp: the measure of the avg kinetic energy of the particles in an object Temp=intensive property (temperature does not depend on the amount of the sample) heat=extensive property(amount of energy transferred depends on amount of heat in the sample) |
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Enthalpy
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the sum of the internal energy of a system
H |
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molar heat capacity
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the energy as heat needed to increase the temperature of 1 mol of the substance by 1 K
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Molar Enthalpy Change
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the enthalpy change for one mole of a pure substance
molar enthalpy change=CT molar enthalpy change=(moalr heat capacity)(temperature change) |
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H=q when...
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you are heating or cooling of substances
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endothermic reactions have _____ enthalpy changes
exothermic reactions have ______ enthalpy changes |
positive
negative |
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Standard thermodynamic Temperature
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25.00 degrees Celcius
used to standardize the enthalpies of reactions, both reactants and products have it |
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Calorimetry
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measures enthalpy change (H)
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Hess's Law
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adding up the equations
the law that states that the amount of heat released or absorbed in a chemical reaction does not depend on the number of steps in the reaction |
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entropy
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the measure of the randomness or disorder of a system
thermodynamic property J/k S |
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a process is more likely to occur if it is accompanied by a _______ in entropy, that is S is ________
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an increase
positive |
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Gibbs energy/free energy
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the energy in a system that is available for work
G=H-TS |
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FILL IN A GIBBS TABLE
RIGHT NOW |
H | S | G | Spontaneous?
----------------------------- - | + | - | yes - | - | +/- | only if T<H/S + | + | +/- | only if T>H/S + | - | + | never |
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H=CT
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change in molar enthalpy when ONLY temperature changes
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surface tension
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the force that acts on the surface of a liquid and that tends to minimize the area of the surface
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intermolecular forces
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the forces of attraction between molecules
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enthalpy of fusion
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the energy added during melting or removed during freezing
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entropy of fusion
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as a solid melts, particle motion increases as it transitions into the liquid state (or other way around)
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triple point
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the temperature and pressure conditions at which the solid, liquid and gaseous phases of a substance coexist at equilibrium
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order on a phase diagram (from left)
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solid, liquid, vapor
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critical point
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the temperature and pressure at which the gas and liquid states of a substance become identical and form one phase
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what are the units for Energy
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Joules
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under what conditions is heat (q) the same as enthalpy (H)
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at constant pressure
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in an endothermic reaction, do the products or reactants have lower energy
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reactants
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are products or reactants more stable in an endothermic reaciton?
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reactants, because you have to give it energy for it to do anything
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what does entropy tell you about a reaction?
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entropy determines the randomness of the particles of a substance
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what does it mean if the sighn for S for a reaction is
A.negative B.positive |
A.if it is negative it will be less likely to happen
B. If S is positive a process is more likely to occur (see gibbs table) |
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What does Gibb's energy tell you about a reaction
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it tells you the spontaneity of a reaction aka whether or not it will happen
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If a reaction has a negative H and a positive S, what will the sign of G be? Is this reaction spontaneous?
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negative
yes it will be spontaneous |
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is condensing an endothermic or exothermic process?`
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exothermic process
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hydrogen bond
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bonds with forces of high electronegativity (right corner)
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dipole-dipole
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interactions between polar molecules
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london dispersion force
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the intermolecular attraction resulting from uneven distribution of electrons and the creation of temporary dipoles
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vapor pressure
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the partial pressure exerted by a vapor that is in equilibrium with its liquid state at a given temperature
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