CHM 230 Exam 2

What is a model that uses electrostatics to explain electronics in complexes?

crystal field

What is a model that uses molecular orbital approach in the structure of complexes?

ligand field

What do colors in transition metal complexes come from

energy HOMO-LUMO gap

What kind of coloration is glowing or light?

emissive coloration

What kind of coloration is paint or clothes?

absorptive coloration

We see the _____color of wavelengths absorbed

complementary

In an octahedral field, what d orbitals are not point at the axis

dxy, dyz, dxz

In an octahedral field, what d orbitals are affected most by electrostatic interaction?

dz2, and dx2-y2

octahedral d1 through d 3 have all _______ electrons

unpaired

octahedral d __ __through d_______ have both high and low spin states

4-7

low spin means less _____ electrons

unpaired

If delta O is less than repulsion between paired electrons than electrons ______ want to pair

don’t

Ligands ____ the d-orbitals of transition metal complexes

split

Electrons fill into the orbitals based of the size of what

delta O

What influences the size of delta O

\-size of metal

\-charge of metal

\-nature of ligand

big metals give a _____ delta O

larger

as the charge on the metal increases, delta O ____-

increases

Delta O increases as you go ___ __to__ _____ across a period

left to right

What is the order of ligands from small delta O to large delta O

halogens< oxygen compounds< nitrogen compounds< carbon compounds

What d orbitals are higher energy for tetrahedral complexes

dxy, dyz, dxz

What d orbitals are lower in energy for tetrahedral complexes

dz2, dx2-y2

Delta T is always ____- than delta O

less

All tetrahedral complexes are ____ spin

high

What square planar d orbitals have the lowest energy

dxz and dyz

What square planar d orbital has the largest energy

dx2-y2

What ions are mostly square planar

d8 (Ni2+, Pd 2+, Pt2+, Au3+, Rh +, Ir+)

The delta SP is very ____-

large

square planar are typically

diamagnetic

What is beers law

absorbance= molar absorptivity x path length x molar concentration

Molar absorptivity indicates how __ a species undergoes a ______

efficiently; transition

a high molar absorptivity means

more photons absorped

What impacts molar absorpitvity

selection rules and geometry

The laporte rule is d-to-d transitions forbidden in ____ complexes

octahedral

Transitions that require the spin of an electrion to change are

forbidden

Tetrahedral complexes tend to be strongly

colored

most transition metals show ___ main electronic transitions

3

What is the equation for energy of transition?

energy= (hc/wavelength)

When more energy is enetering a system than leaving or vise versa it is called a

dynamic system

Enthalpy is hear flow measured at constant

pressure

state functions are

\-size dependent

\-additive

\-value depends on the difference btwn 2 energentic states

what is it called when gas goes to liquid

condensation

what is it called when liquid goes to gas

vaporization

What is it called when a solid goes to a gas

sublimation

what is it called when a gas goes to a soild

deposition

what is a solid going to a liquid

melting

what is a liquid going to a solid

freezing

What process of phase changes are endothermic

melting, vaporization, and sublimation

What processes of phase changes are exothermic

freezing, condensation, and deposition

what does combustion produce

co2 (g) and H20 (l)

What is hess’s law

the summation of enthalpies

What are the standard conditions

25 C, 1 atm pressure, 1 M solutions

In enthalpy you assume that all elements have an enthalpy of _____ in their standard state

0

for enthalpy of balanced thermochemcial reactions you can use the equation

h rxn= hf products - hf reactants

What is the equation for estimating delta H using bond enthalpies?

Hrxn= h broken -h formed

In bond enthalpies phases of matter _____ taken into account

are not

What are the qualities common to spontaneous reactions?

\-release heat

\-form gases

\-form precipiates

\-form compounds with strong bonds

What is the most convient and precise way to measure delta H

using Hf values

What property of spontaneous reactions is hard to measure with enthlapy

forming gases

A _____ is one of any possible configurations in a system

microstate

What is the measure of the number of microstates available to the system being studied?

entropy

entropy ___- with pressure

increases

The _____ of particles increases the entropy of a system

mobility

When a scoop of ice cream melts entropy ____

increases

When a solid is turned into aqueous ions entropy ____

increases

When a liquid and gas turn into a solid and gas entropy____

decreases

What are the units of entropy

J/K

Delta S =

n(S products)- n (S reactants)

reactions that are spontaneous tend to be ___ and have an _______ in entropy

exothermic; increase

What is the equation for delta G

delta G= delta H- (temp(K) x delta S)

for a spontaneous process delta G has to be _____ zero

less than

\-H and + S means the reaction is

spontaneous at all Temps

\-H and -S means the reaction is

spontaneous at low temp

\+H and +S means the reaction is

spontaneous at high temps

\+H and -S means the reaction is

never spontaneous

The best way to calculate delta G is using

free energies of formation

When should you use delta G= delta H- (T x delta S)

when you need to determine TEMPERATURE of spontaneity and when entropy and enthalpy values are available

When should you use delta G- (products)- reactants

when only delta G values are avaible and you only need to determine spontaneity

What does Gibbs free energy have to be in order for a reaction to be spontaneous?

less than O (-)

What state functions do elements in their standard state = 0

enthalpy and Gibbs Free Energy

What are the units of delta G

kJ/mol

The equilibrium constant is ( ) over ( )

products; reactants

What drops out of the K expression

solids and liquids

the molarity of gas is what

mols gas/ Volume container

When reagents are added to a solution the equilibrium will shift

away from what was added

If an endothermic reaction is warmed where will the equilibrium shift

to the right towards the products

What are the top orbitals of an octahedral compound d orbital splitting diagram called?

eg

What are the bottom orbitals of an octahedral compound d orbital splitting diagram called?

t2g

What are the top orbitals of a tetrahedral compound d orbital splitting diagram called?

t2

What are the bottom orbitals of a tetrahedral compound d orbital splitting diagram called?

e

What is the order of square planar diagrams from bottom to top?

(dxz + dyz), dz^2, dxy, dx^2-y^2

What are the values of h and s for line A

h>0, s

What are the values of h and s for line B

h

What are the values of h and s for line C

h>0, s>0

What are the values of h and s for line ~~D~~

h

under what conditions is the top line spontaneous

never spontaneous

under what conditions is the 2 line spontaneous

spontaneous at low temps

under what conditions is the 3rd line spontaneous

spontaneous at high temps

under what conditions is the bottom line spontaneous

always spontaneous