Chem lab 2nd exam

Chemical Kinetics

Chemical Kinetics

branch of chemistry that deals with the rates of chemical reactions, reaction mechanism

Collisions are energetic and of proper orientation

for a reaction to occur it must have these two factors

nature of species, temperature, concentration, catalyst

four factors affecting the rate of reactions

Clock reaction

effects of concentration

as concentration increases; reaction rate also increases

explain the relation ship between concentration and rate of reaction

increased frequency of collisions

why does more concentration result in faster reactions

Lukewaram

in three treatments of Lukewarm, ice bathe and room temp. At which temp is a reaction most like fastest to occur in?

Phenophthalein

acid-based indicator which turns pink when the pH is basic

catalyst

______ speeds up the reaction without being consumed. Recovered unchanged in the reaction and provides an alternative pathway that requires less energy

Increase H+; Increase OH-

Arrhenius definition of acid-base

H+ donor; H+ acceptor

Bronested lowry definition of acid-base

e- acceptor; e- donor

Lewis definiton of acid-base

non-electrolyte

has no dissociation, no conductivity, an example is sucrose (table sugar), alcohol

weak electrolyte

partial dissociation; low conductivity; examples are weak acids and bases and slightly soluble salts

strong electrolyte

total dissociation; high conductivity; strong acids and bases, highly soluble salts

HCl, HBr, Hi, HNO3, HClO4, HClO3, H2SO4

name 7 strong acids

weaker

the stronger the acid the ______ the conjugate base

weaker

the stronger the base the ______ the conjugate acid

Strong electrolytes

completely dissociates in water

Weak electrolytes

partially dissociates in water

CH3COOH + H2O → CH3COO- + H3O+

dissociation of acetic acid in water

Conductivity

how well solutions allow the flow of electrrical charges or ions through it. Expressed in units of siemens per meter/ siemens per centimeter

high; lower

strong electrolytes are ______ conductivities, while weak electrolytes have _____ conductivites

Molar conductivity

it is the conductivity/ molar concentration. Conductivity of a solution containing one mf electrolyte per liter of solution

Fraction dissociation

for weak acids or weak bases only. Measure of the degree to which the acid or base dissociates or ionizes in an aqueous solution. Represents the percentage

Conductivity of weak acid/ Concentration

molar conductivity formula

Solubility

the amount of solute that can be dissolved in a particular amount of solvent at a particular temperature to form a saturated solution. Usually expressed in units of concentration.

Highly soluble, sparingly soluble, insoluble

three classification of salts based on solubility

Sparingly soluble salts

salts having low solubility in water

Unsaturated

the concentration of dissolved solute is less than its solubility at that temperature. Additional solute can still be dissolved

Saturated

The concentration of dissolved solute equals its solubility at that temperature. Addititononal solute can no longer be dissolved

Supersaturated

the concentration of dissolved solute exceeds its solubility at that temperature

favors forward; solution is unsaturated

is Qsp<Ksp

equilibrium; saturated

if Qsp = Ksp

reverse is favored; precipitation will occur

if Qsp>ksp

pH, Complex ion formation, common ion formation

3 factors that affect the solubility of a sparingly soluble salt