QA final exam

millimolar mass

the mass in grams of one millimole of a chemical species

which is not a systematic error

instrumental error
method error/
personal error
gross error

constant error

the magnitude of this error stays essentially the same as the size of the quantity measured is varied

relative error

the absolute error divided by the true error

variance

the square of the standard deviation

discuss how the size of the confidence interval for the mean is influenced by sample size assuming that all other factors are constant

the confidence interval decreases

molar mass

the mass in grams of one mole of a chemcial species

proportional error

these errors increase or decrease according to the size of the sample taken fr analysis

absolute error

the difference between the measured value and the true value

sample standard deviation

standard deviation of a sample of data

coefficient of variation

percent relative standard deviation

discuss how the size of the confidence interval for the mean is influenced by the standard deviation assumign that all other factors are constant

the confidence interva increases

standard error of the mean

the standard deviation of the data set divided by the square root of the number of measurements

discuss how the size of the confidence interval for the mean is influenced by the confidence level assuming that all other factors are constant

the confidence level increases

zwitterion

chemical species that bears both positive and negative charges

bronsted lowry base

a molecule that accepts a proton when it encounters an acid

leveling solvent

shows no difference between strong acids

autoprotolysis

the act of self ionization to produce both a conjugate acid and a conjugate base 

neutralization in terms of the bronted lowry concept

occurs when a reaction involving an acid and its conjugate base is combined with a second reaction involving a base and its conjugate acid

differentiating solvent

reveals different strengths of acids

strong electrolyte

a compound that totally ionizes when dissolved in water

common ion effect

the reduced solubility of an ionic precipitate when one of the soluble components reacting to form the precipitate is added to the solution in equilibrium with the precipitate

weak acid

a compound that only partially dissociates such that there are undissociated molesules and ions in aqueous solution

le chateliers principle

the position of an equilibrium always shifts in such a direction that it relieves the stress

amphiprotic solvent

can act either as an acid or a base depending on the solute

amphiprotic solute

a compound that can act either as an acid or base depending on the situation

conjugate acid of a bronsted lowry base

the potential proton donor formed when a bronsted lowry base accepts a proton

neglecting any effects caused by volume change, what happens to the ionic strength when NaOH is added to a dilute solution of hydrochloric acid

remain unchanged

adsorption

the process by which ions are retained on the surface of a solid

crystalline precipitate

solid particles with dimensions that areat least 10^-4 cm or greater 

particle growth

a process by which growth continues on existing nuclei

precipitation 

the process by which a solid phase forms ad is carried out of solution when the solubility poduct of a chemical species is exceeded

gravimetric volatilization method

the analyte is separated from other sample constituents by converting it to a gas of known composion

stoichiometric ratio

the molar ratio of two chemical sepcies that appear in a balanced chemical equation

titration

measures the quantity of a reagent of known concentration required to react with a mreasured quantity of sample of an unknown concentration

neglecting any effects caused by volume changes, what would you expect the ionice strength to do when NaOH is added to a dilute solution of magnesium chloride?

decrease

digestion

a process in which a precipitate is heated in the presence of the solution from which it was formed (the mother liquor)

Neglecting any effects caused by volume changes, what would you expect to happen to the ionic strength when NaOH is added to a dilute solution of acetic acid?

increase

supersaturation

an unstable state in which a solution contains higher solute concentration than a saturated solution

colloid precipiate

solid particles with dimensions that are less than 10^-4 cm

coprecipitation

the process in which normally soluble compounds are carried out of solution during precipitate formation

salt bridge

provides electrical contact but prevents mixing of dissimilar solutions in an electrochemical cell

standard electrode potential

the potential of a cell consisting of the half-reaction of interest on the right and a standard hydrogen electrode on the left. The activities of all the participants in the half-reaction are specfiied as having a value of unity

oxidation

a process in which a species loses one or more electrons

oxidation potential

the potential of an electrochemical cell in which the cathode is a standardhydrogen electrode and the half0cell of interect acts as anode

liquid junction

the interface between dissimilar liquids. A potential develops across the interface

liquid junction potential

the potential that develops across the interface between two dissimilar solutions

reductant

an electron donor

electrode potential

the potential of an electrochemical cell in which a standard hydrogen electrode acts as the reference electrode on the left and the half-cell of interest is on the right