reaction rates and equilibrium test
some spontaneous reactions appear to be non spontaneous because their rate of reaction is slow (AT, ST, NT)
always true (think of nails rusting- takes a long time but is still spontaneous bc it occurs without an outside force)
activation energy
an energy barrier between reactants and products
the numerical value of deltaG is negative in spontaneous processes because the system loses free energy (AT, ST, NT)
always true
the speed of a reaction can be increased by increasing reactant concentration or decreasing particle size (AT, ST, NT)
always true
there is at least one activated complex in a chemical reaction (AT, ST, NT)
always true
the concentrations of reactants and products in a system at a dynamic equilibrium are always changing (AT, ST, NT)
always true (dynamic = changing, moving)
deltaG
change in gibbs free energy
a catalyst is considered a reactant in a chemical reaction (AT, ST, NT)
never true
the rate order of reaction can be determined from the balanced equation (AT, ST, NT)
never true
in a reversible reaction, entropy will
not change
if Keq= 6.7 x 10-5,
reactants predominate at equilibrium
exothermic reaction
releases energy, products have lower energy than reactants (lower than reactants)
for a chemical equilibrium to be established, the chemical reaction must be
reversible
an indication that an equilibrium system favors the products is
a positive deltaH
spontaneous reaction
a reaction that occurs in a given set of conditions without intervention
endothermic reaction
absorbs energy, reactants have lower energy than products (starts lower gets higher)
an elementary reaction is a one-step reaction (AT, ST, NT)
always true
spontaneous reactions release free energy (AT, ST, NT)
always true
given the change of phase: CO2(g) changes to CO2(s), the entropy of the system
decreases (as molecules change from a gas to a solid, the molecules are becoming more orderly and therefor have less disorder or entropy)
in an irreversible reaction, entropy will
increase
adding heat to an exothermic reaction will shift the reaction to the
left
what explains why the melting of ice is a spontaneous reaction at room temperature and pressure?
melting is accompanied by an increase of entropy
an exothermic reaction is a spontaneous reaction (AT, ST, NT)
sometimes true
an increase in temperature will increase the rate of reactions
sometimes true
entropy will increase in a spontaneous reaction
sometimes true
there is at least one intermediate product in a chemical reaction (AT, ST, NT)
sometimes true
a change in the pressure of a system can cause a shift in the equilibrium position (AT, ST, NT)
sometimes true (only true w/ gases)
what statement explains why the speed of some chemical reactions is increased when the surface area of the reactant is increased?
the change exposes more reactant particles to a possible collision
entropy
the number of ways a system can be arranged, higher the entropy, the more disordered the system
a reaction is spontaneous if
the overall entropy (or disorder) increases
removal of a product always causes the equilibrium to shift toward
the product side
what effect does an increase in temperature have on a reaction in equilibrium
the reaction will shift in the direction that will minimize the effect of this stress, it will shift in the direction that has the fewest gas particles
at equilibrium, what is the rate of production of reactants compared with the rate of production of products?
the same
decreasing the volume in an exothermic reaction will shift the reaction to
the side with fewer molecules
activated complex
the structure that results at the maximum energy point along the reaction path; has characteristics of both reactants and products but higher energy than either of them; not stable, short lived
why does a higher concentration make a reaction faster
there are more collisions per second (only reason for a reaction to be faster due to a higher concentration)
all spontaneous processes release free energy
true