chem unit 3 equilibrium

conditions for chem equil

closed system, rate of forward=rate of reverse, reversible

adding more product will shift

left

removing reactant will shift

left

volume increase causes

pressure decrease shift to side with more particles

adding noble/inert gas

increase pressure without volume change, keep equil

exo equation

a+b->c+d+heat

endo equation

a+b+heat->c+d

temp increases on exo equation will shift

left

enthalpy of exo is

negative

temp decrease on endo will shift

left

giveaways of concent., pressure and temp change on graph

concent. and pressure is sharp increase, concent. is only one pressure is all

temperature is gradual increase of one

Kc formula

[products]/[reactants]

reverse Kc reaction is

1/Kc

double coeffiencts equil constant causes Kc to

square

half of coefficient equil constant will cause Kc to

square root

at Kc<0.001,

mostly reactant can assume initial=at equilibrium

at Kc>1000

mostly product

what does a catalyst do to equil

no shift just reaches equil faster because same impact on both sides due to lower Ea

When Q=Kc the reaction is

at equilibrium

when Q>Kc what needs to happen

shift left to create more reactant

when Q<Kc what needs to happen

shift right to create more product

Ksp formula

[C]^c[D]^d

what does higher Ksp mean

more soluble ionic compound because greater ion concentration

what is a monophonic acid/base with example

that can only donate/accept one proton like HCl and OH-

what is conjugate base of HNO3

NO3- when the acid loses proton

what is conjugate acid for HCO3-

H2CO3 when base gains proton

what is a polyprotic acid/base with example of diprotic and triprotic

can donate/acceptmore than one portion

diprotic - H2SO4, CO3(2-) LOOK AT CHARGE

triprotic - H3PO4

What is an Bronsted-Lowry acid?

H+ donor

What is a Bronsted-Lowry base?

H+ acceptor

what is amphiprotic species and give two examples

that can donate or accept proton depending on what they react with.

eg water and HSO4(-)

acid pH range

base pH range

7

what does Kw=10^-14 mean for pH

pH+pOH=14 OR pKA+pKb=14

Ka formula (acid dissociation constant)

products/reactants

what does large Ka mean

more products, dissociates more readily, stronger acid

Kb formula (base dissociation constant)

products/reactants

what is Kw equivalent to

Ka x Kb=10^-14

pKa formula

-log10(Ka)

what does lower pKa/pKb mean

higher Ka/Kb thus stronger acid/base

assumption for weak acid/base

since Ka/Kb<10^-3, initial concentration is equal to equilibrium concentration

how to choose an indicator

pKA is +/- 1 of indicator

pKa is equivalent to

pH

equivalence point

midpoint of straight line when indicator change

neutralisation reaction

acid+base->salt+water

pH of neutralisation reaction for strong acid and strong base

7

relationship between pKa and pH mid colour change

pH=pKa because change colour when equal parts HIn and In- conc. thus Ka=H+ conc.

pH colour change range

pKa+-1 bc colour change can be observed when conc. HIn=In- and ratio changes by 1:10

pure water concentrations

conc. H+=OH- with pH of 7 in 25 deg. pH can change w temp change but always equal parts

Ksp range

between last conc. with no precipitate and first conc. with predicate

what does smaller Ksp mean

less soluble