Gen Chem 2 Exam 5

amount

Reaction rate (or rate of reaction) - the change in the — of a reactant or product per unit of time

concentration, time

Rate expression - the mathematical representation of the change in species — over — during a chemical reaction

reaction

Average rate of reaction - changes in concentration throughout the — (initial vs. end time)

instantaneous rate

rate at which a reaction is proceeding at a specific time

initial rate

the instantaneous rate at t=0

physical state, temp, concentration, presence of catalyst, chemical nature

what are the 5 factors that may affect the rate of a chemical reaction?

temp, concentration

increase in — or in — of one or more reactants increases the reaction rate

rate, reactants

rate law- mathematical expressions that describe the relationship between the — of a chemical reaction and the concentration of its —

𝑟𝑎𝑡𝑒 = 𝑘[𝐴]^m[𝐵]ⁿ

sum

overall reaction order = the — of the order of each reactant (m+n)

integrated rate laws

relate the concentration of reactants and time; integrates the differential rate law of a chemical reaction using calculus to integrate time and concentration of reactants and products

reactant

half life of a reaction: the time required for half of a given amount of — to be consumed

inverse

there is an — relation between the half-life of a first order reaction and the rate constant, k

constants, longer

faster first order reactions have larger rate — and shorter half lives

slower reactions have smaller rate constants and — half lives

concentration

the half-life of an second order reaction is inversely proportional to the — of the reactant

proportional, orientation, adequate energy

the postulates of collision theory: 1) the rate of a reaction is — to the rate of reactant collisions  2)the reacting species must collide in an — that allows contact between the atoms that will become bonded together in the product   3) the collision must occur with — — to permit mutual penetration of the reacting species valence shell so that the electrons can rearrange and form new bonds

unstable

activated complex: the — species that forms when molecules with adequate energy and orientation collide (short-lived products)

minimum

activation energy: the —energy necessary to form a product during a collision between reactants

collisions

the higher the energy the more — occur the faster the reaction rate

faster

lower activation energy and higher temperature = — reaction rate

reaction mechanism

the step-by-step process by which a reaction occurs

elementary reaction

each step in a reaction mechanism

intermediates

species produced in one step and consumed in another

molecularity

—: the number of reactant entities

unimolecular

—: the reaction of a single reactant entity to produce one or more molecules of products

bimolecular

—: the reaction of 2 reactant entity to produce one or more molecules of products

trimolecular

—: the reaction of 3 reactant entity to produce one or more molecules of products

2NO +F2 → 2NOF

Write the balanced equation of the reaction with the following elementary steps:

 

NO  +  F₂  → NOF₂

NOF₂  +  NO → 2NOF

rate-limiting step

the step within a multi-step reaction that limits the rate of the reaction (the slowest step) at equilibrium rate_forward=rate_reverse

k₁[Cl₂]=k_-1[Cl]²

Derive the equation relating atomic chlorine concentration, Cl to molecular chlorine concentration, Cl₂.

Cl₂ (g)  ⇌ 2Cl (g)  fast

catalyst

increases the rate of a reaction by lowering the required activation energy

rate

catalysts affect the — constant NOT the equilibrium constant

Homogeneous, NO

— catalyst: present in the same phase as the reactants (ex of catalyst —)

heterogenous

— catalyst: present in a different phase than the reactants (ex of catalyst —)

biological, ligase

— catalyst: an enzyme (protein) manufactured in the cells of living things that speeds up the rate of biochemical reactions (ex —)

atmospheric, chlorofluorocarbon

— catalyst: — gases and nitric oxides catalyze the decomposition of ozone