chem 2 mid term 2

Insoluble

S-2, O-2, Co3-2, Po4-3, c2O4-4 unless with na+, K+, Nh4+, No3-

soluble

cl-,br-,I-,F-,s04-2 unless with ag, hg, pb

Electronegativity

increasing as you go right

Atomic radius

increases as you go down

Le chateliers principle

-adding gas reactant or removing product will shift it to the product/right and vice versa

How does increasing volume change things

-increasing volume decreases pressure and concentration, so it goes to the side w bigger coefficients

what changes k

temp only

Effect of temp on equilibrium

In an endothermic reaction increasing temp is like adding more reactant and shifts to product

exothermic is opposite

Endo vs Exo

Endothermic is positive as it is gaining energy from system and exothermic is negative as it releases energy

To find keq

-to reverse equation multiply by 1/keq

-to add multiple to subtract divide

-to double keq² to triple keq³ etc

when can you use keq or assume equiblrium is reached

Only assume equiblirium is reached if there is enough moles which you can check with pv=nrt

Autoionization

water separating into hydronium and hydroxides

Dynamic equilibrium

when rate forward= reverse rate

-only aq reactions, and gas are included in concentration

delta n

(c+d)-(a+b)

Kc

= [C]^c[D]^d/[A]^a[B]^b

kp

= [C]RT^c[D]RT^d/[A]RT^a[B]RT^b

Q=

kc not at equilibrium

if Q>k too many products need reactants to reach equilibrium or opposite

when reactant vs product forward

k>1 product forward

k<1 reactant forward

Ice table

change in moles ir proportional to mole ratio

neutral

hydronium=hydroxide=1×10^-7

when using ice table for kb

14-pOH

Polyprotic acid (more than 1 H+ to donate)

-the more protons you loose the lower the ka

Acid and structure

-atomic size increase decreases ha bond which increases acid strength (trumps electronegativity)

-more electronegativity takes H electron in HA/has more electron affinity so stronger acid

Oxyacid

-E(some random atom)-O(can be multiple)H

-The more electronegative E the stronger the acid, sixe doesnt matter here because H is on oxygen

-higher oxidation number of E=the stronger the E

Oxyacid bases

-its a worse base if it can distribute negative charge more so the bigger it is or the more resonance structures it has the weaker the base

Buffers

have a weak ka and kb

made of acid and conjugate base

VHA=VA-

diluting buffer doesnt affect pH

Buffer ph and pka

[HA]=[A-] pH=pKA

[HA]>[A-] pH<pKA

[HA]<[A-] pH>pKA

How to tell if salt is neutral or acidic or base

-neutral if negative ion is a conjugate base of strong acid and positive ion can not give hydrogen

-acid if it can give a hydrogen and not more basic than that

-base if conjugate of weak acid