General Chemistry II Final Exam

0th Law of Thermodynamics

2 systems are in thermal equilibrium when their temperature is the same

1st Law of Thermodynamics

energy is neither created nor destroyed; its conserved

internal energy equation

∆E = E(final) - E(initial)

increases

When ∆E > 0, energy of the system __________

decreases

When ∆E < 0, the energy of the system __________

added

When q > 0, heat is ______ to the system (+)

removed

When q < 0, heat is ___________ from the system (-)

greater

When w is ______ than 0, work is done to the system (+)

less

When w is ______ than 0, work is done by the system (-)

calorimetry

measurement of heat flow

enthalpy (h)

change in heat constant of reaction at constant pressure

endothermic

when ∆H > 0, heat gained from surrounding making it an ________ reaction

exothermic

when ∆H < 0, heat released to surrounding making it an _________ reaction

Reaction

Enthalpy of __________ (∆Hrxn) - heat of reaction (extensive property) depends on state of reactions and products

Formation

Enthalpy of __________ (∆Hf) - heat needed to form substance from its elements

Bond

_________ Enthalpy - amount of energy required to break a particular bond between two elements in a gaseous state

∑(∆H Bonds broken) - ∑(∆H Bonds Formed)

intermolecular forces

attractive forces that exist between all molecules and atoms

Dispersion Forces

weakest force, present in all molecules & atoms; the magnitude increases with molar mass & number of electrons increase

Dipole-Dipole forces

polar molecules have this force; non-polar molecules induce temporary dipole moment while polar molecules enhance existing dipole moment

hydrogen bonds

when a hydrogen is directly bonded to oxygen, nitrogen, or fluorine (ex: holds DNA strands together)

ion-dipole attraction

mixture of ionic compounds with polar molecules

polarizability

the ease with which its electron cloud is distored

vaporization

from liquid => to gas; escape liquid becomes a vapor; higher temp = higher rate of evaporization

increases

rate of vaporization ________ as temperature increases, surface area increases and strength of IMF decreases

dynamic equilibrium

when molecules are leaving & exiting at the same rate

vapor pressure

pressure exerted by vapor on a liquid

boiling point, melting point

when IMF increases, _______ & __________ increase

decrease

when IMF increases, there is a _________ in vapor pressure

longer

a ______ chain has higher IMF due to the increases surface area for interactions to occur

mass percent concentration

(mass of solute)/(mass of solution) x 100%

molarity (M)

moles of solute / liters of solution

saturated

a solution that has the solute & solvent in dynamic equilibrium is _____________

unsaturated

a solution with less solute than saturation is ___________

supersaturated

a solution with more solute than saturation is _____________

mole fraction

moles of solute / total moles

decreases

solubility of gas ________ as temperature increases

ions

electrolytes form ______ in solutions

reaction rates

the change in concentration of reactant or product with time; (concentration) / (time)

necessary for reaction to take place

collision theory (i.e. particles must collide), proper orientation, & energy of collision ≥ threshold level of energy

increase

An increase in temperature causes in __________ in kinetic energy of particles which leads to more frequent collisions

activation energy

energy different; in order to be effective, collisions between particles must exceed an energy threshold

first order

t1/2 does not depend on initial concentration

second order

t1/2 is inversely proportional

0th order

t1/2 is directly proportional