exam 2 chem 1230

question

when does a precipitate form?
answer

when the attractive forces between ions are large
question

what are the exceptions for I, Cl, and Br?
answer

Ag, Hg, Pb, Cu, Ti
question

what are the exceptions for SO4?
answer

Ca, Sr, Ba, Pb
question

what are always soluble?
answer

NH4, group 1A, NO3, ClO4, Clo3, C2H3O2
question

solution
answer

homogenous mixture of 2+ substances
question

solvent
answer

major proportion
question

solute
answer

minor proportion
question

colligative properties
answer

affected by concentration of particle the solute contirbutes to the solution
question

what are examples of colligative properties?
answer

osmotic pressure

vapor pressure lowering

boiling point elevation

freezing point depression

 

question

colligative molality
answer

change in freezing point or boiling point of a solvent when solute is added
question

what is the equation for colligative molality? (Mc)
answer

Mc = i x m
question

how do you find molality and what are the units?
answer

moles of solute / kg of solvent
question

what is i?
answer

vant hoff factor; # of particles produced when a solute dissolves
question

what is the equation for delta T?
answer

delta T = Kf * Mc
question

what is Kf?
answer

the freezing point depression constant of solvent
question

what are the properties of lauryl acid?
answer

non hazardous but prolonged contact may cause skin irritation
question

what equipment is used in experiemnt 8?
answer

crystallization dish

graduated cylinder

beaker

thermometer

tongs

spatula

hot plate

question

when is equilibrium established?
answer

when the rates of the forward and reverse reactions are equal
question

what are the properties of HCl?
answer

corrosive, irritant, use fume hood, injures eyes and skin
question

what are the properties of AgNO3?
answer

dark spots
question

what is the effect of raising temperature with respect to Le Chateliers principle?
answer

equilibirum shifts to the higher energy side
question

what are the reactions studied in experiment 9?
answer

CoCl4^2- + 6 H2O -> Co(H2O)6^2+ + 4 Cl^-

Fe^3+ + SCN^- -> FeSCN^2+

question

when are reactants favored? products?
answer

when K is low

when K is high

question

what are titrations?
answer

stoichiometric volume of one reactant of known concentration (titrant) is required to react with another reactant of unknown concentration (analyte)
question

how is the concentration of the analyte determined?
answer

from the concentration of the titrant and stoichiometry of reaction between them
question

what is in the buret?
answer

titrant
question

what is in the flask?
answer

analyte
question

what is in indicator
answer

a substance that changes color near the equivalence point
question

how is an indicator chosen?
answer

when the equivalence point is near the end point
question

what is the endpoint?
answer

point at which the color change occurs
question

what should you consider when setting up a titration?
answer

buret measured to nearest .01 mL

make sure no air bubbles in buret tip

condition buret

fill buret below 0 mark

close stopcock

question

what happens if you dont condition the buret?
answer

the volume of titrant will increase

the moles of analyte will be overestimated

question

what happens if you condition the flask with analyte?
answer

increase in volume of titrant

overestimation of moles of analyte

question

mass %
answer

moles of acid / moles of base x 100
question

how do u go from moles to mmol
answer

1 mol = 1000 mmol
question

what is the difference when doing conjugates?
answer

a H+
question

conjugate base of an acid
answer

remove an H+
question

conjugate acid of a base
answer

add H+ to base
question

what subsances are corrosive?
answer

acetic

Nh3

Hcl

Naoh

question

what substances are irritants?
answer

acetic

NH3

HC;

question

how do u find [H3O+] given pH?
answer

H+ = 10^-pH
question

how do u find pH given [H+]
answer

pH = log[H+]
question

enthalpy
answer

amount of heat energy absorbed at constant pressure
question

entropy
answer

number of ways energy can be distributed in a system
question

system
answer

part of universe being studied
question

surroundings
answer

part of universe that interacts with system being studied
question

spontaneous
answer

lowers energy of system
question

nonspontaneous
answer

amount of energy supplied to cause process to occur
question

heat of reaction
answer

when reactants react completley at STP
question

electrodes
answer

metal strips
question

cathode
answer

reduction
question

anode
answer

oxidation
question

saltbridge
answer

allows ions to travel from one 1/2 cell to other
question

voltmeter
answer

calculates potential difference between oxidizing and reducing agents (mV -> V)
question

how do you find Ecell
answer

Ecell = Ecathode – Eanode
question

if H < 0 and S > 0
answer

spontaneous
question

if H > 0 and S < 0
answer

non spontaneous
question

H < 0
answer

exo
question

H > 0
answer

endo
question

S < 0
answer

spontaneous
question

G > 0
answer

nonspontaneous

Get instant access to
all materials

Become a Member