Week 7 Review

what is buffer effectiveness, and what are the two things it is affected by?

what is buffer effectiveness, and what are the two things it is affected by?

limit to how much acid or base can be added until pH significantly changes, relative and absolute amounts of acid and base

what is buffering range?

pH range that buffer is most effective in

what is buffering capacity? how does it increase

amount of acid or base buffer can neutralize, increases when absolute amount of acid and base increases

buffers designed to neutralize acid,base generally have more

base, acid respectively

what formula do you use to calculate determine pH when its less than 7?

CaVa-CbVb/Va+Vb

what formula do you use to calculate determine pH when its more than 7?

CbVb-CaVa/Va+Vb

in strong base - strong acid titrations, descirbe pH and concentraions of equilibrium point

pH is 7, H+ and OH- conc are equal

in strong base weak acid titrations, describe pH and concentrations at equilibrium point

pH is more than 7, there is more OH- than H+

in strong acid weak base titrations, describe pH and concentrations at equilibrium point

pH is less than 7, more H+ than OH-

what is the trend of Ka’s of titrations of polyprotic acids

Ka’s get weaker the more they hydrolyze

What pH range of pH indicators would you use for a weak acid and strong base?

an indicator with pH > 7

What is Ksp, solubility product, for the following reaction?

[Ca2+]^3[PO43-]^2

trend for Ksp

the more insoluble a compound is, the smaller Ksp is

Q<Ksp

unsaturated solution, no precipitate

Q=Ksp

saturated solution, no precipitate

Q>Ksp

supersaturated solution, precipitate forms

identify whether the following reaction has any (in)soluble components and forms precipitate

BaSO4 is insoluble, precipitate forms ZnCL2 is soluble, no precipitate

identify whether the following reaction has any (in)soluble components and forms precipitate

NH4Cl is soluble, no precipitate CaCO3 is insoluble, precipitate forms

for compounds with low solubility, the formation of precipitate depends on the condition

Q>Ksp

What is s=?

s=[Ag+]=Ksp/[Cl-]

What is s=?

s=[Pb2+]=Ksp/[Cl2-]

What is s=?

s=[CL-]/2=root(Ksp/2[Pb2+]

to selectively choose a precipitate, look for the reaction with the ____ Ksp

lowest

if we slowly add ag+ to this solution, which will precipitate first?

AgBr

complex ions

ions that form by combining a cation with several anions or neutral molecules

ligands

attached ions or molecules of complex ions

formation constant Kf for the following?

Kf=[AgNH32]/[Ag][NH3]^2