DAT Gen Chem

Find: element *not* in standard state Ex: Which of the following diatomic molecules has a *nonzero* standard enthalpy of formation? O2 (g) H2 (g) N2 (g) Br2(g) F2(g)

Br2 is *(liquid)* at standard state = so Br2(g) has nonzero enthalpy of formation Enthalpy of formation for elements in standard state = 0 Gas = H,N,O,F,Cl + noble gases Liq = Br, Hg Solid = everything else!

Find: Amount liquid *added* to solution, given 1 volume, 2 conc EX: How much water should be *added* to 10 mL of 3.00 M HCl(aq) in order to *dilute* it to a 2.00 M solution of HCl(aq)?

DILUTION Q! *M1V1=M2V2* Q. asks how much is *added* to original solution, so *subtract* by original amount V2 - OG = amnt *added* 15 - 10 = 5 ml

Entropy ΔS decreases with what changes?

Decrease temp decrease volume = increase pressure decrease in gas mol

Density equation

Density = mass/volume

What is mass defect and what is it used to calculate?

Difference between a nucleus' calculated mass and it's *actual* mass Used to calculate *nuclear* *binding* *energy*

Gas solubilty trend with pressure

Direct = more pressure forces gas into liquid

Graph of conc vs time What is the relationship between half life and conc. in a zero-order rxn?

Directly proportional

Gases Volume and # of gas molecules (n) 1. What is relationship? 2. What law?

Directly proportional Avogadro's law

Gases Volume and temperature 1. What is relationship? 2. What law?

Directly proportional Charles' law (heating a marshmallow)

Relation between pressure and temperature?

Directly proportional (Gay-lussac's law) P1 T1 = P2 T2 Use % increase to do calculation : (New-OG)/OG

A Lewis acid is

E- ACCEPTOR

A Lewis base is

E- DONOR

What are the 4 types of questions on Ksp?

Calculate molar solubilty Calculate Ksp Calculate solubility for common ion effect Determine if precip will occur

When asked to calculate pH of bases, how do you start?

Calculate pOH then plug --> pOH + pH = 14

mercury (I)

Hg₂²⁺

Halogens have _____ e- affinity, meaning:

High e- affinity = high thirst for e- because they want to feel like noble gas

Combustion rxn is

Hydrocarbon + O2 --> CO2 + H2O

Which of the following has the smallest atomic radius?

Hydrogen = most abundant in *universe* Oxygen = most abundant in *crust*

The 7 strong acids are:

Hydroiodic acid Hydrobromic acid Hydrochloric acid Chloric acid Perchloric acid Sulfuric acid Nitric acid

Find: Atomic weight of unknown element, given molar mass EX: If compound X3P2 has a molar mass of 135 g/mol, what is the *atomic* *weight* of the unknown element X? Strategy?

Molar mass = Atomic weight A + Atomic weight B So turn into equation and solve 3X + 2P = 135

Find: molar solubility Given: PbSO4 in 4.0x10^-2 M Pb(NO3)2 Ksp for PbSO4 1.6 x 10^-8

Molar solubility = *x* in ICE table! Write out what both dissolve into and find *common* *ion* Ksp = [react]

Given some *molar* solution, what equation would you use to solve for molar mass of a compound?

Molarity (M) equation! then plug into molar mass eq = g/ mol

Of the 4 classes of solids, which is weakest?

Molecular solids Held together by IMF (like H2O)

Surface tension can be described by:

Molecules at the top are experiencing downward and side-to-side attraction from neighboring molecules, a thing film forms that can bare some weight

Acidity trends of oxyacids (HBrO4)

More oxygens = more acidic (resonance) HClO4 > HClO3 If the number of O is the same: the more electroneg heteroatom = the more acidic *HClO4* > HBrO4

When pressure is decreased, eq. rxns shift in which direction?

Most # gas mol

When volume is increased, eq. rxns shift in which direction?

Most # gas mol

Find: [concentration] of molecule in solution, given Ka EX: What is the *concentration* of [CN-] in a 0.2 M solution of HCN? The *Ka* of HCN is 5 × 10-10.

*Ka* = weak acid! Question twist!! instead of asking for [H+], it asks for [CN-] but since they dissociate in equal amounts, they are equal

Gases behave most ideally under conditions of

*LOW* pressures *HIGH* temperatures

Water molecules in an aqueous solution will have the *strongest* interactions with ions with which of the following characteristics? Small or large charge? Small or large size?

*Large* charge *Small* size larger charge = stronger interaction w/ H20 small size = means *more* interactions

Nitrite

NO₂⁻

Nitrate

NO₃⁻

Kp is an equilibrium constant in terms of:

Pressure! [products/reactants]

Reduction always occurs at the a. anode b. cathode

RED CAT! *Red*uction always occurs at the *cat*hode

Decreasing temperature is the same thing as ______ heat to the eq. rxn

REMOVING HEAT

To increase Keq, shift rxn to

RIGHT (products)

If Q<K Which way will rxn shift?

RIGHT --> (toward products)

Adding solute does what to boiling point?

Raises! solution will avoid vaporizing because it doesn't want to evaporate and leave solute in low entropy state

Rate *only* has to do with the [conc] of what

Rate = k[reactants]

What mass (in grams) of MnSO4 (150 g/mol) is required to prepare 5.0 *m* of MnSO4 solution with 500 g of water?

Realize Q. deals with *m*olality Convert 500g → 0.5 kg Multiply answer by MW to find answer in grams 2.5mol * 150g/mol = 375g

As pressure *decreases* at a *constant* temperature for the phase diagram of *water* , which of the following can occur? Crystallization Sublimation Fusion Vaporization

Realize that the phase diagram of water has (-) slope!! Sublimation (sol→gas) Vaporization (liq→gas) Crystallization (liq→sol)

In thin layer chromatography (TLC), what does the Rf tell us?

Retention factor is a # that tells us how far up the TLC plate a compound travels, thus

In eq rxn, which direction will rxn shift if more reactant is added?

Right (away from added)

____ acids have large Ka values (10^pos. num)

STRONG acids have large Ka values

What type of apparatus would you use for solvent extraction?

Separatory funnel

How is it that O2 and He have the same average kinetic energy at the same temperature?

Since He is the lighter molecule, it has to move faster!

What 2 things *dont* appear in equalibrium constant expressions

Solids & liquids! never include these in expression

What doesnt appear in equilibrium constant expressions?

Solids and liquids!

All compounds containing CH3COO- are ______

Soluble!

All compounds containing SO4 2- are ______ except for compounds containing:

Soluble! Sr2+ Ba2+ Hg2 2+ Pb 2+

What if theres a compound that has both soluble and insoluble part? What will it be?

Solubles trump insolubles

Find: Standard enthalpy of formation (ΔH°f) The ΔH for which of the following reactions is the standard enthalpy of formation (ΔH°f) for sodium chloride?

Na(s) + 1/2Cl2(g) → NaCl

Van Der Waals *real* gas equation What makes it different from ideal (PV=nRT )?

Need to know: 1. Circled terms 2. The closer circled terms are to *zero*, the more "ideally" gas will behave!

What equation do you use to interconvert between Ecell and E°?

Nernst equation! n: # moles of e- transferred Q = [prod]/[reac]

Gamma decay

No change in protons or neutrons

How does adding a catalyst affect eq.?

No shift! Only affects the *rate* at which they arrive

How does adding an inert gas affect eq?

No shift! Inert gas is any gas that isn't already in rxn

Can strong electrolytes form equilibrium rxns?

No! Once they dissociate they cant go back (Same w strong acids) But weak electrolytes can form eq. rxn

In *electrolytic* cells, the flow of electrons is from: (electrolysis)

Non-spontaneous (+G, -Ecell) reductant <---- oxidant (recharging a battery)

In extractions... What is usually on top? What is the *exception* & why?

Nonpolar organic layer on top *except* when using chlorinated solvents (DCM) cuz theyre denser than water

Which of the following has the smallest atomic radius? A. K+ B. Ca^2+ C. Cl- D. Ar E. S^2-

Notice that they all have the same # of e- = *isoelectronic* series So whichever has *more* protons, will be *smaller*

Hydroxide

OH⁻

Molarity is used for what colligative property?

OP!

the "p" in pKa stands for

-log

-log(6*10^-4)

-log(6*10^-4) (ex - 1) *.* (10-6) = 3.4

pH =

-log[H+] = exponent of conc!

pOH =

-log[OH-]

pOH =

-log[OH-] = exponent of conc!

-q means

-q = exothermic

Positron

0 +1

Beta particle

0 -1

Gamma particle

0 0

STP is

0 C (273 K) 1 atm (760 mmHg or 760 Torr)

The enthalpy of formation ΔHf of any element in its *standard* *state* is

0 kJ/mol at 298 K and 1 atm

Dalton's Atomic Theory

1) elements are composed of atoms which can combine in ratios to form compounds. 2. Atoms differ according to size and mass

Alkali metals form stable ____ ions

1+

*C*alories is equal to ____ calories or ___ kilocalorie

1,000 calories 1 kilocalorie

Find: 1. Direction of rxn shift given E° 2. New Ecell when increased 3. How will change affect Ecell Ex: Zn + Cu2+ → Cu + Zn2+ E°= +1.10v In which direction will the reaction shift if [Cu2+] is *increased* to 10M

1. Adding Cu2+ on left will cause rxn to shift *right* 2. *Nernst* Ecell = E° - (0.0592/n) * log (Q) n = # of e- transferred Q = [products]/[reactants] 3. If rxn is shifted *right*, = Ecell will increase If rxn is shifted *left* = Ecell will decrease

Find: products of electrolysis What are the products of the *electrolysis* of KI?

1. Break up rxn into red & oxidation rxns 2. determine Ecell for both 3. compare competing H20 rxn!! Whichever is *more* *positive* will be spontaneous, and will occur! Products will be the products from more favored rxns! (I2 & H2)

Find: E° (standard cell potential) What is the standard cell potential (E°) for the following rxn? Zn + CuSO4 → Cu + ZnSO4

1. Break up rxn into red & oxidation rxns 2. determine Ecell for both & add them

Find: How many e- are *transferred* in this reaction? *ACIDIC* cond steps

1. determine whats oxidized/reduced 2. *Balance* -everything but O and H - O → +H20 -H → +H+ -total charge -> + e- -half rxns -> coeff

Find: How many e- are *transferred* in this reaction? *BASIC* cond steps

1. determine whats oxidized/reduced 2. *Balance* -everything but O and H -O → +H20 - H+ → OH- -combine all H+ & OH- → H2O & elim excess - total charge→ + e- - half rxns -> coeff

What are the units for the (linear) y-axis of an integrated rate law graph for: second-order

1/[concentration]

Bp of water =

100°C

Ka * Kb =

10^-14 = kw

[H+] =

10^-pH

[OH-] =

10^-pOH

Find: atom with highest oxidation state What're 2 ways to approach this?

1. draw out lewis structures and see which has *most* bonds to oxygen 2. calculate oxidation state based on oxidation numbers

Find: ΔH Given the following enthalpy information, what is *ΔH* for the following rxn? Ch4 + 2O2 → CO2 + 2 H2O Given: table of rxns and corresponding ΔHs

1. go through each equation and see if it lines up with original eq and determine what needs to be done either a *flip* (Eq 2) or multiplied by coeff (Eq 4) sum up ΔH's

What is waters autoionization? Kw =

1.0 x 10^-14 @ 25 C

At STP, 1 mol of *any* gas =

22.4 L

Find: Final temperature, given *specific* *heat* EX: 10 kJ of heat was applied to a 150 g sample of copper at 50°C. The *specific* *heat* of copper is 0.39 J·g-1·°C-1. What is the *final* *temperature* of the copper after the heat is applied in °C?

Specific heat equation *q=mCΔT* q = heat m = mass Cp = specific heat ΔT = (final - initial) Don't forget to convert 10 kj → J (x1000)

When give a set of possible quantum numbers and ask which is *not* possible, where do you start?

Start w *l* assign shell 0=s 1=p 2=d 3=f Then look at corresponding *n* and see if it lines up on periodic table with l look at *ml* last

What is henry's law?

States that a in sealed vessle containing dissolved gas, gas pressure and concentration are proportional

Electron affinity measures the:

The *ease* with which an atom *gains* an electron or Energy released when atom *gains* e- E- affinity trends follow electronegativity trends

The *titrant* is the ______ in the experiment The *titrand* is the:

The *titrant* is the solution w/ KNOWN [conc] - IN the buret *titrand* is the solution w/ UNKNOWN [conc] - IN the Erlenmeyer flask

3rd law of thermodynamics

The entropy of a perfect crystal is zero when the temperature of the crystal is equal to absolute zero

In a multistep reaction, which is the rate determining step?

The step with the *largest* activation energy Ea (largest hill)

Why should one *slowly* add acid to a beaker of water rather than water to a beaker of acid?

To ensure there is enough water to absorb the heat released and prevent splashing

Technique to separate mixtures of two or more volatile liquids that have close boiling points (~25C)? a. fractional distillation b. distillation c. recrystallization d. extraction

a. fractional distillation

Phase diagrams The pressure/temp combo at which all three phases exist at the same time, in equilibrium w each other a. triple point b. critical point c. line of equilibrium d. normal melting point and boiling point

a. triple point

Non-metal oxides + water --> ______ solutions

acidic

Amphiprotic is a substance that can:

act as both a H+ acceptor and donor (Arrhenius and bronsted) H2O

The species with the highest amount of energy, found at the tip of the activation energy peak

activated complex step

Colligative properties are properties of a solution that change as you:

add more solute!

Hess's law says that if you

add multiple rxns together, the new overally *ΔH* is equal to the combined sum of all the individual ΔH's

What kinds of molecules have dispersion forces?

all of them

Different structural forms of the same element are:

allotropes

Ion sizes: More electrons = ___ size Less electrons = ___ size

anions = Increase size cations = decrease size

e- always flow from ___ to ___

anode --> cathode

In *electrolytic* cells, the: anode= cathode=

anode = (+) cathode = (-)

in *voltaic/galvanic* cells, the anode is ____ and the cathode is _____

anode = neg cathode = positive

In *electrolytic* cells, the anode is ____ and the cathode is _____

anode = positive cathode = neg

The anode metal ____ mass, while the cathode metal _____ mass

anode metal *loses* mass cathode metal *gains* mass

Kc is an equilibrium constant in terms of:

concentration! So [A] [B] [C] [D] are in terms of *molarity* (mols solute/L solution)

Gas to liquid

condensation

Main purpose of electrolysis is to:

convert compounds like H20 NaCl into their parent elements = H2, Cl2

What are the two categories of solids?

crystalline and amorphous *crystalline* - long range order (consistent lattice) - sharp defined melting temp - break evenly *amorphous* - short range order - no consistent structure - broad range melting points - irregular breakage pattern

Liquid to solid

crystallization/freezing

polar molecules exhibit ____ interactions

dipole-dipole intermolecular forces (nonmetal + nonmetal) HCl

Relationship between osmotic pressure and solute conc.

directly proportional Osmotic pressure increases as solute conc. increases

relationship between gas solubility and pressure

directly related

If solution goes from liquid ---> solid, What change in entropy will be seen?

disorder ---> order *(-ΔS)*

Rf value =

dist. substace/ dist solvent high Rf = non polar low Rf = polar

how do you convert kPa to atm?

divide by 100!

Metasl ____ contain anions

do not

What is a Lewis acid?

e- acceptor

What is a Lewis base?

e- donor

Hund's rule

e- dont pair up until they have to Every orbital in subshell must be singly occupied before any one orbital is doubly occupied

Aufbau principle

e- fill lowest energy orbital first

Remember! for dihydroxy species, how does *[OH-]* dissociate?

each [OH-] = 100%

All strong acids are *also* strong ______

electrolytes! (HCl, HBr, HI, H2SO4, HNO3, HClO4, HClO3)

A voltaic cell's ability to provide energy is called its

electromotive force or electrode potential

Ionic bonds are held together by

electrostatic attractions

Which elements on the periodic table can form hyper octets? (more than 3 bonds?)

elements in row 3 and down EX: N can't P *can*

Going from solid--> liquid --> gas exothermic or endothermic?

endothermic (+G) + enthalpy + entropy

What is the third law of thermodynamics?

ensures that a closed system will eventually reach a thermal equilibrium

Liquid to gas

evaporation

The mol. forces of cohesion ______ the forces of adhesion

exceed

Going from gas --> liquid --> solid exothermic or endothermic?

exothermic (-G) - enthalpy (-H) - entropy (-S)

Isoelectronic series

group of elements that all have the same number of electrons

Enthalpy is the amount of

heat-energy a substance contains

Substances with *high* melting points will have ____ IMF

high (takes more energy to break them apart to turn to liquid)

In *galvanic/voltaic* cells, the flow of electrons is from:

high E --> low E -G + Ecell

High heat of vaporization is another way of saying what?

high boiling point

The smaller the heat capacity (C), the ____ the final temp

higher

Higher IMF = _______ Boiling point

higher IMF are responsible for molecules boiling points

Why do atoms get larger as you go down a group?

higher energy "n" shell = larger size

Density

how heavy a substance is

Titration curve shows how the _____ pH changes when _____ is added

how the *titrand's* pH changes when *titrant* is added

Viscosity is?

how thick a substance is The higher the viscosity, the more slowly it pours

The solubility of alcohols decreases as you add more

hydrocarbons because hydrocarbons are *nonpolar*

Octet rule exceptions

hydrogen wants 2 Be wants 4 B & Al wants 6

How do you calculate change in freezing point that a liquid will experience when a solute is dissolved in it?

i = increases as # of mol. goes up Ex: NaCl dissolves into Na+ and Cl-, which is 2 things. So, i = 2

Sublimation can be used when you have an

impure solid that happens to sublime (solid -> gas)

adding e- will _____ the size of the atom

increase

To increase pressure, you can do 2 things

increase force or decrease area Cuz P=F/A

The decrease in atomic radius from *left* → *right* across a period can best be explained by

increase in *eff.* nucelar charge (increase in # of protons) more H+ = e- closer together

+s =

increase in disorder & increase in movement solid -> liq -> gas sublimation, vaporization, fusion s is *always* positive!!!

Entropy ΔS increases with what changes?

increase temp increase vol = dec. pressure increase gas mol

Accuracy of ideal gas law ____ as gas behaves more "ideally"

increases

Ionization energy trend Exceptions:

increases up and to the right Be & N - takes more energy to strip these e- cuz relatively stable w/ full outer shell

The _____ _____ _____ effect is responsible for the increase in atomic size moving down groups

increasing e- shielding

The _______ ______ _______ is responsible for the decrease in atomic size *across* the period table from L to R

increasing effective nuclear charge

LDF increase with:

increasing molar mass! bigger the molecule, the more LDF it has

State function depend only on

initial and final states (entropy) For example: at 25C and 1 atm of pressure, the *entropy* of 1 mol of water is 70 J/K. If you have 1 mol frozen water at 1atm pressure and warm it up to 25C, its entropy will be.... 70 J/K!

State function is a function that only depends on the:

initial and final states of the system, not HOW they got there

Soluble or insoluble? Ag+

insoluble

Soluble or insoluble? AgCl

insoluble

Soluble or insoluble? AlPO4

insoluble

Soluble or insoluble? CO3 2-

insoluble

Soluble or insoluble? Hg2 2+

insoluble

Soluble or insoluble? HgCl2

insoluble

Soluble or insoluble? MgS

insoluble

Soluble or insoluble? PO4 3-

insoluble

Soluble or insoluble? Pb2+

insoluble

Soluble or insoluble? PbI2

insoluble

Soluble or insoluble? S2-

insoluble

All compounds containing CO3 2- are ______ except for compounds containing:

insoluble NH4+ Alkali metal cations

All compounds containing PO4 3- are ______ except for compounds containing:

insoluble NH4+ Alkali metal cations

All compounds containing OH- are ______ except for compounds containing:

insoluble NH4+ Alkali metal cations Ca 2+ Sr 2+ Ba 2+

All compounds containing S2- are ______ except for compounds containing:

insoluble NH4+ Alkali metal cations Ca 2+ Sr 2+ Ba 2+

relationship between gas solubility and temp

inverse think of soda

What is the relationship between bond strength and bond length

inverse !

How is activation energy related to k & rxn rate?

inversely

Pressure and volume are _______ related

inversely

Relationship with boiling point and vapor pressure?

inversely related

What type of IMF dominates when NaCl dissolves in water?

ion-dipole

dipole-dipole doesn't apply to ___ compounds, only molecular compounds

ionic (metal + non)

_____ is adding or removing e- from atoms The trend?

ionization Increases w/ electroneg! (Up and to the right)

The salt bridge:

is a source of counter anions that balance out charges

An ____ process is one in which enthalpy remains constant (∆H = 0).

isenthalpic

An _____ process is one in which entropy remains constant (∆S = 0).

isentropic

An ______ process is one in which pressure remains constant (∆P = 0)

isobaric

An ______ process is one in which temperature remains constant (∆T = 0).

isothermal

Heinsenberg Uncertainty

it is impossible to determine a subatomic particles *position* and its *momentum* w/ perfect accuracy

Half-life calculations ask to solve for *rate* *constant*, what equation do you use?

k = (0.693)/(t1/2)

Find: *Rate* of rxn 2A + B → 3C B = 2nd order A = 0 order How does doubling the conc of A, and increasing [B] by factor of 3 affect rate?

k=[reactants] ONLY

Ideal gas constant (R) for pressure in *kPa*

kPa = 8.314

More sheilding = ____ size

larger (directly proportional)

Decrease in effective nuclear charge = ____ size

larger (inverse)

The *more* soluble compound will have a ____ Ksp value

larger Ksp

Fission reaction involves

larger nuclei decay --> smaller pieces

The larger the atomic weight, the ______ the melting point

larger!

2 domains 0 lone pairs

linear 180

6 domains 4 lone pairs

linear 90

5 domains 3 lone pairs

linear 90,120

The temperature at which _____ is the same as the temperature at which *condensation* occurs Condensation point =

liquid boils Condensation point is when ΔG=0

What are the units for the (linear) y-axis of an integrated rate law graph for: first-order rxn

ln[concentration]

Molecular solids have a _____ melting point

low because of weak IMF holding them together

The larger the heat capacity (C), the _____ the final temp

lower

If theres a constitutional isomer, the *more* brancing, the ___ the bp, the ___ the mp

lower bp higher mp

Adding solute does what to freezing point?

lowers! Because, the solute gets in the way of the molecules making rigid structure

If rxn has -H, we treat heat as a _______

product

When K > 1, ______ is favored at equilibrium

products

mass number =

protons + neutrons

How do catalysts lower activation energy?

providing an alternate pathway/mechanism between reactants and products

Column Chormatography is used to: Another name for it is:

purify compounds Silica gel chromatography

Crystallization is generally for:

purifying solid based on *solubility* Product precipitates out of a liquid and is later captured through *filtration*

Find: q Ex: You used a bomb calorimeter, whose *heat* *capacity* is 2000 cal/°C, to measure a banana's heat content (calories). During the banana's combustion, the *temperature* *changed* from 15 °C to 20 °C. What is this banana's *q*?

q = -CΔT -C = heat capacity ΔT = 20-15 (can leave in °C)

Find: q for specific *amount* of substance

q = mcΔT add *m*! the substance's mass

When gases escape through a narrow slit, lighter gases (gases w lower molecular weights) effuse _____ What law is this

quicker Graham's Law of Effusion

The lattice structure of *ionic* (NaCl) substances ____ the melting temp

raises!

The step that determines the overall speed of the reaction is

rate-determining step

If rxn has +H, we treat heat as a ______

reactant

When K < 1, _____ is favored at equilibrium

reactants

Alpha decay

reduces mass #

What is the *reducing* *agent* in the following rxn? Zn(s) + 2HCl(aq) → ZnCl2(aq) + H2(g)?

reducing agent = is *oxidized* = loss of e- *oxidized* = goes up in charge 1. Assign oxidation numbers to each of species

Nonpolar and polar molecules tend to:

repel eachother

Specific heat *(C)* is the amount of energy

required to increase *temp* of 1g by 1C or 1K

The larger the molecule, the _______ dispersion forces it has

more

Why do atoms get smaller as you move across a period?

more protons = increased effective nuclear charge (Zeff) = smaller size Zeff = sucking in more e-

Polyprotic acids have

more than one H+ per molecule

Whatre the 3 rules for sig figs? What's the rule for sigfigs when multiplying/dividing?

multiplying/dividing: answer has same sigfigs as # w/ fewest sigfigs

Equation for solving Mol. weight given D,P,R,T

mw = DRT/P

Nernst eq Formula: WHen do you use this?

n = # e- transferred Q = [prod]/[react]

How much L of acid do you need to *neutralize* base? What equation do you use?!

n1M1V1= n2M2V2

Quantum numbers n = l = ml = ms =

n= principal (shell) l = azimuthal (subshell) 0=s, 1=p, 2=d 3=f ml = magnetic (specific orbital) -l -> +l ms = spin (up/down) +1/2 or -1/2

Reactions between acids and bases are called: This is a type of ______ (double-displacement) rxn They always make:

neutralization reactions *Metathesis* rxn They always make *H2O* and a *salt*

Pauli exclusion principle

no 2 electrons can have the same 4 quantum numbers

For precipitation problems,

no ICE Write balanced eq (might have common ions) write solub. expression Plug in [conc] values Q>Ksp = precip! Q<Ksp = NO precip!

calorie (cal) is the amount of heat

required to raise 1g of liquid water by 1C = 4.19 J

Find: Partial pressure of gas, given *Kp* EX: CuO(s) + CO2(g) <--> CuCO3(s) + heat At a certain temperature, *Kp = 2.0*. What is the *partial* *pressure* of CO2 (g) in the above reaction?

no solids no liquids in Kp expressions! 2 atm = 1/(PCO2) PCO2 = 0.5 atm

When determine which species is getting oxidized and reduced, do you count the coeff?

no! just calculate all the oxidation numbers

Equalibrium constants, can we use rate constant to help determine?

no! rate has nothing to do with conc. of products (equalib)

______ are inert unreactive gasses

noble gasses

Dipole-dipole forces are when

non ionic molecule has polar bond - causes molecules to have partial charges H-Cl

On TLC plate, the higher the spot, the more____ a compound a. polar b. nonpolar

nonpolar

A *negative* E° would be good for what type of cell

nonspontaneous *elecrtolytic* cuz it has energy source

When neutrons and protons combine into a nucleus, the energy required to keep them together is called:

nuclear binding energy

A buffer is a solution that: Made by combining

resists pH change weak acid + conj. base

What comination of the following 2 elements would most likely have the *smallest* *bond* *length*? a. low ionization & high metallic b. high ionization & high e- affinity c. high metalli & high atomic radius d. low e- affinity & low ionization

smallest bond length = *smallest* size 1. start by drawing periodic table with trends 2. see that an atom w/ a small size will be both high in ionization & electron affinity

The *nucleon* are the particles that make up the nucleus. The nucleus is comprised of...

nucleon = *neutrons* + *protons* Alpha and beta particles are comprised of nucleons, but are not referred to as nucleons themselves

atomic number is

number of protons

When given Ksp, its a giveaway that compound is a

solid! (s)

All compounds that contain NO3- are:

soluble

Soluble or insoluble? AgNO3

soluble

Soluble or insoluble? C2H3O2

soluble

6 domains 0 lone pairs

octahedral 90

Soluble or insoluble? Group 1 metal cations

soluble

Soluble or insoluble? NH4+

soluble

Soluble or insoluble? Na2CO3

soluble

Soluble or insoluble? Zn(CH3COO)2

soluble

All compounds containing Br- are ______ except for compounds containing:

soluble! Ag+ Hg2 2+ Pb 2+

All compounds containing I- are ______ except for compounds containing:

soluble! Ag+ Hg2 2+ Pb 2+

All compounds that contain Cl- are _________, except for cmpds containing

soluble! Ag+, Hg2^2+, Pb 2+

If two balloons of equal volume have *same* temperature, what can be said about their kinetic energy?

same temp = same kinetic energy

How do you induce crystallization in recrystallization?

scratching side of class to provide a nucleation site or use seed crystal

When a question says @ at *sea* *level*, what information does this point to?

sea level = 1 atm

5 domains 1 lone pair

seesaw 90,120

Distillations are generally to:

separate 2 *miscible* liquids in solution by boiling point Miscible = form homogeneous mixtures

Decantation is generally used to

separate liquid from solids by pouring the liquid carefully off the top

Filtrations are generally to:

separate solid from liquid by pouring through a filter

a buchner flask can attach to a vacuum pump and is used in

separation of solid from liquid

more protons generally means ______ size

smaller because more protons draw IN more e-, decreasing atomic radius

Increase in effective nuclear charge = ____ size

smaller (Inverse)

Less shielding = ____ size

smaller (directly proportional)

The *less* soluble compound will have a ____ Ksp value

smaller Ksp

on TLC plate, Smaller Rf value = Larger Rf value =

smaller Rf = POLAR larger Rf= NONPOLAR

Fusion reaction involves

smaller nuclei combine to form larger nuclei (stars)

TLC plate: Rf values Are _____ specific, so changing it will change Rf value Can increase Rf by adding a more _____ solvent

solvent specific polar

a *positive* E° would be good for what type of cell

spontaneous *galvanic/voltaic* cell

6 domains 2 lone pairs

square planar 90

6 domains 1 lone pair

square pyramidal 90

___ are chemical or physical properties that only depend on the initial and final states of the system, *not* how they got there

state functions - entropy - enthalpy - energy work (w) and heat (q) are *not* state functions

Solid to gas

sublimation, endothermic

heat curves shows how

substance changes from a solid -> liq -> gas, as temp is *raised*

What does it mean when Q=K

system has reached equilibrium

A system vs surroundings?

system is the chemical rxn, surroundings is everything else around it

A mixture can be separated by ____ means

physical

How do you solve neutralization equations?

plug values into

Extraction technique rely on using :

polar and nonpolar solvents

Extraction is used to separate... Glassware used: Which layer is on top? Bottom? Except when:

polar compounds from nonpolar compounds separatory funnel Top (organic nonpolar) Bottom (aqueous polar) Except when solvent contains Cl! then its reversed

Electrolytic cells need a ____

power source - which changes the anode --> (+) cathode --> (-)

6 domains 3 lone pairs

t-shaped 90

5 domains 2 lone pairs

t-shaped 90,120

The average speed of two different gas molecules depends on what

temperature *and* mol. weight

4 domains 0 lone pairs

tetrahedral 109.5

Osmotic pressure is the amount of pressure:

that is applied to STOP osmosis

Colligative properties depend *only* on

the [conc] of the solute particles vapor pressure boiling point freezing point osmotic pressure

whats wrong with these K units? m^-1s^-2

units K *never* include s^-2!!!!

If problem gives P, T and gas density and asks to identify which gas it is, what equation do u use

use values to calculate molar mass then ID the gas

What is oxidation number of a nonmetal

usually negative *Oxygen* is usually -2 (except in H2O2) *H* is +1 when bonded to nonmetals is -1 when bonded to metals F is always -1 Other halogens are usually -1 but can be + if bonded to O

What happens to volume if temperature increases

volume increases! Directly proportional

Life exists because of what property of water?

waters density - if water as a solid was denser than water as a liquid, ice would form and sink to bottom of lake killing all life

Substances with *low* melting points also have ______ IMF

weak

Why type of force do noble gases exert?

weak LDF! low melting point low boiling point

Which of the following could be used to prepare a buffer solution? What do you look for?

weak acid + conj base Cannot prepare buffer w/ strong acid!!!!

Dispersion forces are

weak attractions between nonpolar molecules caused by temporary dipoles that develop when molecules bump into each other weak but make it possible for nonpolar molecules to form liquids and solids

What is Le Chatelier's principle?

when the amount of reactants or products in an equilibrium rxn are changed, rxn will shift in whichever direction returns it to original eq. state

Equation for work and pressure

work = -PΔV "w = -PAV"

Find: X in hydrated salt EX: A sample of *hydrated* magnesium sulfate, MgSO4 • xH2O, weighs 21.0 g. It is placed inside of an oven until all of the water is vaporized, the anhydrous form weighs 12.0 g. What is the *value* of *x* in the *hydrated* *salt*? MgSO4 = 120 g•mol-1.

x = mol H20/ mol MgSO4 anhydrous: only salt, no water

Difference beween intermolecular and intramolecular forces?

*INTER* = between molecules (IMF) *INTRA*= within molecules (metallic, covalent)

+q means

+q = endothermic

Work to pressure equation +w = -w =

+w = surroundings do work on system (compression) -w = system does work on surroundings (expansion)

How do you determine what the bronsted lowry base and acid are?

*ACID* L --> R L <-- R Acid = which one donates H+? *BASE* L --> R L <-- R Base = which one accepts H+?

Acidic salts solubilities increase by adding:

*BASE*

Find: buffer solution What 2 ways can buffers be formed? What can *NOT* be a buffer?

*Buffers* 1:1 *weak* + *conj* 2:1 *weak* + *strong* *Cant* be strong + strong

Find: Time to *plate* out cmpd EX: What amount of *time* (in seconds) would it take to *plate* out 0.50 kg of Ag from molten AgCl with a *current* of 100 amps? (atomic weight of of Ag = 100 g/mol)

*Electroplating* (Its nF) "its enuf" F= 100,000 t = ? I = 100 n = 1 mols = convert 0.5kg Ag → g Ag

Find: if entropy (ΔS) increases or decreases Ex: Indicate if each of the following reactions or processes will have a *positive* or *negative* *ΔS*, and if they are entropically favorable or entropically unfavorable

"Is rxn more ordered on the right or left?" more ordered on *left* = +ΔS = entropically favorable more ordered on *right* = -ΔS = entropically unfavorable (g) + (g) → (g) + (g) since all are (g), count moles! 6 mol → 7 mols = +ΔS, favorable (s) → (aq) = +ΔS, favorable (g) → (g) 2 mol → 1 mol = -ΔS, unfavorable (s) →(aq) = +ΔS, favorable

Formula to calculate % change

% change = (new-original)/ original

Find: Resulting nuclide 206/82 Pb *emits* two alpha particles and one beta particle. Which of the following is the resulting nuclide?

*Emits* = subtract

What can be assumed from a molecule that has strong IMF? with regards to: BP Viscosity Surface tension Vapor pressure

*High* BP *High* viscosity *High surface tension *low* vapor pressure

Find: Amnt produced in *electrolytic* cell ZnCl2 is *electrolyzed* with a current of 7.00 *amperes* for 3 *minutes*. Which of the following is equal to the maximum amount of Zn(s) that is produced in *grams*? (1 faraday = 96,500 coulombs).

(I) = amps/current (T) = time (sec) (MW) = molecular weight of the product (n) = # e- transferred (F) = Faraday constant (~100,000) Only calculate w/ MW if asked for product in *grams*

ΔS = (entropy)

(Sum of products) - (sum reactants) ΔS *can* be + or -

ion-dipole interactions

(metal + non) Ionic substances NaCl dissolved in polar

Find: Partial pressure of gas, given total pressure A mixture of gas is composed of 0.5 mol Ar, 1.5 mol He, and 2.0 mol of N2. What is the *partial* *pressure* of N2 in the mixture if the total pressure is 0.95 *atm?

(mol of gas/ total gas) x total pressure

How do you analyze a rxn order graph that isnt straight?

*0* order = verticles & horizontals shrink (linear) *1st* order = verticals shrink horizontals constant *2nd* order = verticals shrink, horizontals grow

When alcohol is placed in a glass buret, it creates a *concave* meniscus. Which of the following is the cause of this phenomenon?

*Concave* meniscus = particles of the liquid are more strongly attracted to the container (adhesion) than to each other (cohesion) *Convex* meniscus = particles in the liquid have a stronger attraction to each other (cohesion) than to the material that makes up the container (adhesion).

When would you use ice table? Vs When do you just plug into Kc expression?

*ICE* Missing *more* than one [conc] *Kc Expression* Only missing 1 [conc] amount

Basic salts solubilities increase by adding:

*ACID*

An _______ process is one in which heat energy remains constant (∆q = 0).

*adiabatic* no heat lost or gained

In *electrolytic* cells, cations flow toward ___ anions flow toward ___

*cat*ions flow toward *cat*hode *an*ions flow toward *an*ode

Gas → liquid

*condensation*

____ is heat transfer due to direct contact via molecular agitation within a material

*conduction*

___ is heat transfer due to the motion of a fluid

*convection*

___ is heat transfer due to the motion of a fluid or gas (circulation of heat)

*convection*

Liquid → Solid

*crystallization* (freezing)

Gas → solid

*deposition*

What type of apparatus would you use for condensation of volatile gases?

*distillation*

An *exothermic* reaction at equilibrium will proceed at a: ____ rate while its Kc _______ at higher temperatures

*faster* *decreases* *exothermic* = heat is product Increasing temp = adding heat

Solid →liquid

*fusion* (melting)

With a 1st order rxn, the half-life is _____ of the initial concentration of the reactant

*independent* Half-life is *constant* and rate only varies w/ temperature

In covalent substance(CCl4), melting involves the breaking of the ____ bonds

*inter*molecular bonds between molecules CCl4 *-* CCl4 *not* the bonds between the C-Cl4 atoms (intra)

Molecular solids (like ice) are held in place by ____ forces

*inter*molecular forces

Which of the following compounds *conducts* *electricity* in an aqueous solution? MgCl2 C12H22O11 O2(g) PBr3(l)

*ions* in solution will conduct electricity look for cmpd that can dissociate! *MgCl2*! The rest are covalent

When Q<K the rxn shifts... When Q>K the rxn shifts.... When Q=K the rxn shifts... When Q=0 the rxn shifts...

*left* Q*>*K *<<*LEFT Q*<*K *>>*RIGHT Q = K no shift Q = 0 *>>*RIGHT always put Q first Shift will be *opposite* of arrow

The equivalence point during a titration is the point in an acid-base reaction where equivalent

*moles* of acid and base have been reacted; it is the point where equal moles of acid react with equal moles of base.

What is the *normal* vp of a liquid?

*normal* vp= sea level pressure = 1 atm

Find: Lable phase change diagram given *normal* The phase diagram of a substance is given below. Estimate the normal boiling point and *normal* freezing point of the substance

*normal* = 1 atm so look at the phase changes at 1 atm

Anode is the site of

*oxidation* AN OX

Remember! for polyprotic species, If *[H+]* is more than 1 x 10^-7, (-8, -9 , -10, -11 etc) then pH =

*pH* = ~7

___ is heat transfer via electromagnetic radiation

*radiation*

___ is heat transfer via electromagnetic radiation (no medium in-between)

*radiation*

Cathode is the site of

*reduction* RED CAT

Solid → gas

*sublimation*

For any equilibrium rxn, increasing the ____ will increase the rate

*temperature*

Liquid → gas

*vaporization* (boiling)

Alkaline earth metal characteristics Which group are they in?

+ low ionization energy + dont react *as* violently w water Group 2A

alkali metal characteristics (3) Which group are they in?

+ low ionization energy + react explosively w water + form ionic cmpds Group 1A

Name state functions

+ mass & density + volume & pressure + entahlpy & entropy + gibbs free energy

Name non state function

+ work + heat

Buffers work within what range around pH?

+1 -1 range Ex:pKa 4.6 Buffer would have pH range of 3.9-5.9

What are characteristics of ionic solids? (3)

- high melting point - brittle - hard NaCl, MgO

What are characteristics of network covalent solids?

- high melting point - hard - nonconducting (C - diamond), quartz

What are characteristics of molecular solids?

- low melting point - nonconducting H2, CO2

What are characteristics of metallic solids?

- variable hardness & melting point (depends on strength of bond) - malleable - conducting (Fe, Mg)

A spontaneous rxn will occur if

-ΔG -ΔH +ΔS If these cond. are met, rxn is spontaneous at *any* temperature Any other combination of ΔH and ΔS will only be spontaneous at *certain* temperatures

-ΔH is +ΔH is

-ΔH = *exo* +ΔH = *endo*

-ΔS = more +ΔS = more

-ΔS = more *disorder* +ΔS = more *order*

Neutron

1 0

Proton

1 1

How many atoms are in simple cubic unit cell?

1 atom atoms at corners

1000mL of water weighs

1 kg 1000ml = 1 L = 1 kg

To be aromatic, a compound must be what 3 things

1. Cyclic&conjugated pi system 2. No sp3 3. 4n+2 pi e-

To determine a compounds (H20) enthalpy of formation ΔH equation

1. First write H20 being formed --> H20 2. Break it up into its parent molecules H2 + O2 ----> H20 3. Add coeffiecents to *left* side so that it equals right H2 + 1/2 O2 ----> H20

Find: standard cell potential of voltaic cell given 2 half rxns Ex: Ered = -0.28 V Ered = -0.136 V

1. Flip the sign of whichever is *more* *negative* Ered = -0.28 V (more neg) Ered = -0.136 V Since first is more neg, flip the sign (+0.28) and this becomes the oxidized rxn Eox = +0.28 Ered = -0.136 2. Add!

Reducing agent (reductant) is ______ To identify a reducing agent, its the element that has a:

1. Reducing agent *IS* oxidized (Has e- to give up) 2. *negative* oxidation #

Steps to find spectator ions

1. Write correct formula & partner swap & balance 2. Determine solubility of each 3. redraw w/ (aq) separated 4. Spectator ions are the ions that are the same on both sides! (the ones that are crossed out)

What are 3 rules for determining major resonance contributor?

1. all atoms = full octet 2. least formal charges on atoms 3. (-) are on more electroneg species

Steps to find Net ionic charge?

1. balance & assign solubility rules 2. split all (aq) in half 3. cancel out like terms (spectator ions)

Find: ΔH Given the following enthalpy data, what is the ΔHrxn for the following reaction? 2H2 + O2 → 2H20 H-H = 400 kJ O=O = 500 kJ H-O = 450 kJ

1. balance eq 2. draw out lewis structure of molecules 3. fill in values under lewis structures

Collision theory

1. both mol. must collide 2. both must collide w/ enough energy (to get over Ea) 3. must collide w/ correct orientation

What are 4 types of intermolecular forces ranked by strength?

1. ion-dipole 2. H-bond 3. dipole dipole 4. Dispersion forces

Which of the following could you add to *increase* the solubility of (x compound)?

1. look at the salt (acidic, basic, neutral) If salt basic = add acid If salt acidic = add base

To perform electrolysis, setup needs to contain ions that are flowing freely. You can accomplish this what 2 ways

1. melt reactants (molten) 2. dissolve ions in solution (aqueous)

Find: Spontaneteous or nonspontaneous? EX: When Mn and Zn metals react in a *galvanic* cell according to the equation below, will the reaction be spontaneous or nonspontaneous? What will be the products of this reaction? 1. Mn + Zn → 2. Na + Fe2+ → ?

1. no rxn!! Whenever *both* reactants have 0 oxidation state, no rxn will occur cuz one must be oxidized one must be reduced 2. red: Fe2+ → Fe ox: Na → Na+ 0.44V *+* 2.71V - 2.27 V *dont forget to *FLIP* sign of oxidation redpot!

How do you solve neutralization problems? EX: What volume of O.5M H2SO4 is needed to *neutralize* 250 mL of 0.5M KOH?

1. notice we have acid + base 2. *neutralize* determine how many OH- arise from base determine how many H+ arise from acid plug into *n1M1V1*=*n2M2V2*

Asked to identify the conjugate base of a particular acid: Steps?

1. remove H 2. replace H w/ (-) charge

What are the 3 ideal gas assumptions?

1. vol or size of each ind. gas molecule is insignificant *(most accurate @ low temps) 2. Gas molecules collisons w eachother are perfectly elastic (no IMF) *(most accurate @ high temps *and* weak IM forces) 3. Avg kin. energy of gas depends only on systems temp

Steps for solving Ksp problem

1. write balanced eq 2. write eq. expression 3. solve for whatever missing

What're the 3 ways to claculate rxns overally *enthalpy* change ΔH?

1. ΔH = prod - react 2. adding rxns and ΔH values to arrive at final 3. using bond enthalpy values to calculate [ΔH broken - ΔH formed\]

pH + pOH =

14

pKa + pKb =

14

pOH + pH =

14

pKb =

14 - pKa 14- (-log)(Ka)

pKa =

14 - pKb 14 -(-log)(Kb)

____ and ___ react in the presence of pure oxygen

1A alkali metals 2A alkaline earth metals Elements furthest to left will react vigorously w/ oxygen because they want to get rid of e- to feel like noble gas

Remember! for diprotic species, how does *[H+]* dissociate?

1st H+ = 100% 2nd H+ = not all the way

[H+][OH-] =

1x10^-14

How many atoms are in body-centered cubic?

2 atoms atoms at corners and body center

Polyprotic titrations H2SO4

2 pKa values

An unknown gas has a density of 1.79 g•L-1 at *273K* and *1* *atm*. Identify the gas. How do you solve this?

273 K and 1 atm = *STP*!!! @ STP = 1 mol = 22.4 L/mol Plug into density eq! D = M/V

To make a buffer by combining a weak acid + strong base you have to combine them in what ratio?

2:1 weak acid: strong base

A compound is anti-aromatic if it fails what criteria

3. 4n+2

How many classes of solids are there?

4

alpha particle

4 2

How many atoms are in face-centered cubic?

4 atoms atoms at corners and face centers

Titrations: What is the pH equivalence point of: Strong acid/Strong base

7

What does a heat curve show us?

A = Solid only B = Sol. and Liq C = Liquid only D = Liq and Gas E = Gas only

Titrations: What is the pH equivalence point of: Weak base/ strong acid

< 7

Titrations: What is the pH equivalence point of: Weak acid/strong base

> 7

What represents a physical transformation

A physical change does *not* produce a new substance or change the composition, it changes its *physical* form Ex: boiling water (l→g) Chemical changes - rusting - combustion - dissociation

Increasing temperature is the same thing as ________ heat to the eq. rxn

ADDING HEAT

Oxidation always occurs at the a. anode b. cathode

AN OX! *Ox*idation always occurs at the *an*ode

Accuracy vs. Precision

Accuracy: how cole measurement is *to* *reality* Precision: how close series of measurements are *to* *eachother*

Acidity trends in binary acids (HCl, HBr, HI) Across a row? Down a column?

Acidity increases as you go across a row --> due to *electronegativity* Acidity increases as you go down a column due to *size*

In a rxn coordinate diagram, what is delta E or Ea?

Activation energy - energy investment to initiate rxn

For which salt is the solubility *higher* in HCl than water? AgCl BaF2 PbI2

Adding acid (HCl) will *increase* solubility if anion is the conj. base of a *weak* acid!! AgCl → Ag+ Cl- BaF2 → Ba2+ 2F- PbI2 → Pb2+ 2I- Notice that Cl- and I- are the conj. bases of *strong* acids (HCl, HI) So the solubility of BaF2 will be higher in HCl because F- is the conj base of a *weak* acid

_______ form stable +1 ions

Alkali metals

______, M, react w oxygen to forma compound w formula MO

Alkaline earth metals

What equation do you use to calculate activation energy (Ea)? How is rxn speed related to rate constant, k?

Arrhenius equation Rxn speed is directly related to rate constant, k

Difference between an Arrhenius acid and a Bronsted lowry acid?

Arrhenius: H+ donor in *water* Bronsted-lowry: H+ donor

Proton --> neutron

B-decay (Positron emission) Electron capture

Neutron --> proton

B-decay (B-emission)

Phase diagrams The pressure/temp combo beyond which liquid and gas coexist at the same time (indistinguishable) a. triple point b. critical point c. line of equilibrium d. normal melting point and boiling point

B. critical point

Bonds Has low melting point, doesnt conduct electricity a. ionic b. molecular c. metallic d. network covalent

B. molecular

Technique to separate mixtures of two or more volatile liquids? BP difference is (>25C) a. fractional distillation b. simple distillation c. recrystallization d. extraction

B. simple distillation separates mixtures of two ore more volatile liquids

Find: g of substance *consumed* Ammonia is formed according to the reaction below. A chemist mixes 21 grams of nitrogen gas and 18 grams of hydrogen gas in a 2.0 L vessel. How many *grams* of hydrogen gas will be *consumed*? N2 + 3H2 → 2NH3

BCC! 2. convert → mol 3. based on balanced, which is *limiting*? (one w less mols 4. limiting (coeff/coeff) 5. convert mol → g

Converting amount reactant → amount product H2SO4 + 2KOH → K2SO4 + 2H2O How many moles of K2SO4 are produced from *2.5L* of *0.3M* KOH and *1L* of *0.3M* H2SO4?

BCP! Determine *limiting* reactant, then use that to compare ratio of product When given: *[M]* and *L*, multiply to get convert to mols

Boiling point _________ the higher up you are due to:

BP decreases because the higher you get in the air, the less atmospheric pressure you experience, therefore the easier it will be for molecules to "boil"/escape

How do you balance redox reactions under *acidic* conditions?

Balance 1. everything except O and H 2. O → +H20 3. H → +H 4. Charges → +e-

Find: Volume of 1 product, given initial mass (g), STP Hydrogen peroxide (H2O2, 34 g/mol) decomposes into water vapor and oxygen gas. How many *liters* of water vapor are produced from the decomposition of 17.0 g of H2O2 at *STP*?

Balance eq Convert to mols Coeff to find mols of unknown STP -> 1 mol of any gas = 22.4 L

Find: How many e- are *transferred* in this process?

Balance half-rxns! 1. ID what is getting oxidized/reduced 2. Cross out cmpds that only exist on one side 3. write out half rxns 4. Add e- to balance individually 5. multiply by e- to get both rxns to equal = thats your answer

How do you find Ksp?

Balanced eq ICE table (set i = 1 for solid plug given sol. in for [X] (solubility) Disregard x if ksp is smaller than 10^-3

What is the reduction potential table based on?

Based on the reduction of H+ -> H2 = Standard Hydrogen Electrode (SHE)

Why is h bonding so strong?

Because N, O, F are so much larger and more electroneg than H that the great differential charge attracts them to eachother/ adjacent molecule

Find: Final [conc] in EX: 100 mL of 0.50 M CaCl2(aq) is mixed with 100 mL of 0.25 M H2SO4(aq). What is the *final* *concentration* of [Ca2+] in this solution? CaSO4 is insoluble in solution.

Ca2+ + SO4-2 → CaSO4

Acetate

CH₃COO⁻

Thiocyanate

CNS-

Cyanide

CN⁻

To *extract* these below, use_______ solvent COOH: Phenols: Amines:

COOH: NaOH or NaHCO3 Phenols: NaOH Amines: HCl

What're the 5 ground state e- configuration exceptions you need to know?

Chromium Copper Silver Gold Molybdenum

Gases Given: Pressure, volume, temp, number of moles (n) 1. What is relationship? 2. What law?

Combined gas law

Solve for molar solubility of (s) in this solution, given Ksp What kind of question is this & where do you start?

Common ion Q! 1. Write out balanced eq (dissociation) 2. Write out Ksp [reactants] 3. ICE 4. Solve for X (molar solubility)

Adding compound to solution of solid and solving for molar solubility is what kind of question?

Common ion question ICE table Solve for [x]

Find: [conc] in titration 25 mL of an unknown *diprotic* acid was titrated with 0.5 M *NaOH*(aq). If 50 mL of NaOH were required to reach the equivalence point of the *titration*, what is the *concentration* of the unknown acid?

Concentration = M Given 2 Volumes diprotic acid + monoprotic base → use *normalities*! n1M1V1 = n2M2V2

Chromite

CrO₂⁻

Which of the following solutes would decrease water's freezing point by greatest amount, per mol of solute added? A. NaCl B. NH4NO3 C. NH4Cl D. Na2SO4 E. Sucrose

D! because it breaks into 3 ions and A-C breaks into 2 And sucrose breaks into 1

All of the following are properties of gases EXCEPT one. Which one is the EXCEPTION? A. easy to compress B. occuypy more volume than liq/solids from which they form C. expand to fill containers D. effective conductors of heat E. exert a force on interior surface of their container

D! gases are *not* effective conductors of heat

Technique to determine relative abundance of each compound in a liquid mixture a. distillation b. thin layer chromatography c. Recrystallization d. gas-liquid chromatography

D. Gas-layer chromatography

How do you calculate Ecell?

Ecell = red. potential Ereduction (@ cathode) Eoxidation (@ anode) + Ecell = -G = spontaneous - Ecell = +G = nonspontaneous

What is equation for Graham's law of effusion?

Effusion rate G1/effusion rate G2 = SQRT(MW 2/MW 1)

Convert empirical formula --> molecular formula

Empirical: lowest whole # ratio of elements molecular formula: *actual* formula multiply subscripts by whatever factor

1st law of thermodynamics

Energy cannot be created or destroyed

What is the first law of thermodynamics?

Energy cannot be created or destroyed ΔU = q - W internal energy = heat - work W = -PΔV

Describe relationship between energy of photon, freq, and wavelength

Energy of photon *increases* = freq *increases* = wavelength *decreases*

What is the second law of thermodynamics?

Every energy transfer or transformation *increases* the entropy of the universe.

2nd law of thermodynamics

Every energy transfer or transformation increases the entropy of the universe (must be positive)

Find: Amnt of cmpd that will be electroplated EX: If a 20-amp *current* passes through molten BaCl2 for 30 m, how many *grams* of Ba are produced?

F = 100,000 n = 2 I = 20 t = 1800 s multiply mol by molecular weight to get g's

T/F Elements in the same row tend to have similar chemical properties

F. Elements in the same *group* tend to have similar chemical properties. elements in same row share *no* similar properties

How would you calculate formal charge?

FC = (valence e) - (dots) - (bonds)

What is the correct chemical name for FeCl2?

FeCl2 = iron (II) chloride Ionic cmpd = non + metal Determine charge of non (-1)(2) = -2 Determine charge of metal +2 Only use prefixes (di-chloride) when naming cmpds of *2* non-metals

Example colligative properties

Freezing point BP Osmotic pressure

Which of the following can act as both an oxidizing agent *and* a reducing agent? NO3 -1 Co F -1 MnO4 -1 H2O2

Find a substance that: Answer: H2O2 H2 = +1 O2 = -1

Find: Limiting reactant EX: Hydrogen gas and nitrogen gas *react* to produce ammonia. How many *liters* of ammonia can be *produced* from 2 liters of hydrogen gas and 2 liters of nitrogen gas at STP?

Find out which reactant is going to run out first and *limit* our ability to produce ammonia gas Since quantity is given in a *volume*, don't have to convert to mols! (At STP) 1. Balance (N2 + 3H2 → 2NH3) 2. Calculate how many mol NH3 made from first reactant, then second 3. Smaller = limiting reactant When we have *all* *gases*, volumes & mols are directly proportional to each other

Find: affect of adding electrolyte In which pH category would the salt KNO3 fall into?

First, split apart compound KNO3 → K+ NO3- Notice that NO3- is the conj base of a *strong* acid (HNO3) Strong acid = weak conj base (no pH affect) Weak acid = strong conj base (increase pH) So NO3 = weak conj base → has no affect on pH KNO3 = neutral

Find: Final temp EX: What is the *final* *temperature* (TFinal) of a 10.0 g ingot of silver that starts at 120 °C and is placed in 20.0 g of liquid H2O at 40 °C, keeping in mind the following: Csolid silver = 0.25 J/gC Cliquid water = 4 J/gC

First: write down all the info for both water and silver, *separately* then plug into equation and set equal to eachother! mcΔT = *-*[mcΔT] But remember as water gains heat, silver loses exact same amount so put *-* in front of silvers -[mcΔT]

When deciding if a rxn is spontaneous or not, and given either ΔH, how do you figure it out?

Gibbs free energy eq! 1. determine ΔS by seeing if system gets more ordered = -ΔS more disorder = +ΔS *ΔG=ΔH-TΔS*

In a nuclear capture/fusion reaction looks like

Give off energy

In nuclear decay(fission or emission), the reaction looks like

Give off energy

What is the *final* *pressure* of a 100 L gas that is initially at 2 *kPa* and *-23°C*, but is then heated to *227°C* at a constant volume?

Given P1 T1, T2 Solve for P2 Combinded gas law!

What is the periodic trend for elements standard states?

Green = gas Black = solid Red = liquid 298 K (25C) 1 atm So the ΔH of formation of any of these elements in their standard states = 0!!!

The *enthalpy* (H) of a system of gas is dependent on what?

H = U + PV Pressure, volume, and internal energy

A Bronsted base is

H+ ACCEPTOR

A Bronsted acid is

H+ DONOR

What is a Bronsted-Lowry base?

H+ acceptor

What is a Bronsted-Lowry acid?

H+ donor

hydrogen carbonate

HCO₃⁻

Gases behave more ideally at ____ temps and ____ pressures

HIGH temps LOW pressures

hydrogen sulfite

HSO₃⁻

hydrogen sulfate

HSO₄⁻

dihydrogen phosphite

H₂PO₃⁻

dihydrogen phosphate

H₂PO₄⁻

hydronium

H₃O+

If we know all *but* *one* of the following, P,V,n, or T, then the ______ enables us to calculate the unk one

Ideal gas law PV = nRT

What is the zeroth law of thermodynamics?

If 2 systems are in thermal equilbrium with a third system, then all three systems are in thermal eq. w/ eachother A=B B=C then A=C

What is the *molarity* of a 25 mL solution that was prepared by dissolving 5.05 g of KNO3 in water?

If asking for *molarity*, just directly use equation!! Remember to convert mL → L by moving dec. 3 places

Find: Ratio change (gases) A fixed sample of an ideal gas at 298K occupies a certain volume x at a certain pressure y. If the volume of the gas is *increased* to 2x, what will the pressure of the gas be in terms of y?

If theres a *change* in any variable, then use combined gas law pv/nt = pv/nt Rearrange equation for value you're looking for then plug in and solve

What are the rules for hess's law

If you reverse a rxn, the ΔH of the new reversed rxn has same value but opposite sign ΔHforward = *-*ΔHreverse If you multiply rxn by coeff, do the same to ΔH

Soluble or insoluble? OH-

Insoluble

Which are stronger? Intramolecular forces or inter molecular forces?

Intramolecular! (Forces within molecule)

Gases Volume & pressure 1. What is relationship? 2. What law?

Inverse Boyles (Pushing on balloon)

Gas solubility trend with temperature

Inverse - because gas molecules move faster as temp goes up, causing more gas mol. to escape and leave liquid (why soda is served cold)

Relationship between solute and vapor pressure?

Inversely related

Which types of solids *do* *not* conduct electricity? (3)

Ionic solids Covalent network solids Molecular solids

Weak base (Kb) formula for [OH-]

Ka = [products]/[reactants]

Given that the Kb of CH3NH2 is 1.8 x 10-6, what is the pH of a 0.2 M aqueous solution of methylamine? Steps?

Kb = 1.8 * 10^-6 0.2 M solution (reactant) Do ice table in head by plugging values into Kb expression -> solve for x = [OH-] Kb = *[prod]/[react]* = (x)(x) / 0.2 = x^2 / 0.2 = 1.8*10^-6 x = 6*10^-4 = [OH-] pOH = *-log*[OH] = *-log*(6*10^-4) = 3.4 14 - pOH = pH 14 - *3.4* = 10.6

Weak acid (Ka) formula for [H+]

Kb = [products]/[reactants]

What characteristic could we use to determine compounds purity? The machine?

Melting point melting point detector

Which has the highest energy? A. infared rays B. Visible light C. UV rays D. x-rays E. Gamma rays

Memorize this order!!! Lowest → highest longest → shortest wavelength

What tool could u use to identify unk gas?

Mercury manometer

To decrease Keq, shift rxn to

LEFT (reactants)

If Q>K which way will rxn shift?

LEFT <-- (toward reactants) opposite arrow head

When pressure is increased, eq. rxns shift in whichever direction:

Least # gas mol

When volume is decreased, eq. rxns will shift in which direction

Least # gas mol

In eq rxn, which direction will rxn shift if reactant is removed?

Left (toward side that was removed)

The strong bases are:

LiOH NaOH KOH etc

In eq rxn, how do we tell which way rxn will shift when temperature is changed?

Look @ delta H! -H = exothermic (heat is a *product) +H = endothermic (heat is a *reactant*)

Looking at a titration curve, how can you quickly tell which solution it came from?

Look @ the number of equiv. points or *vertical* areas on line that will = # of H+ in solution This graph has 2 equivalence points so acid must have 2 H+

How do you analyze a unknown compound given quantum numbers

Look at *l* first! Then n Then ml then ms

What are the neutral anions?

Look at these when determining if salt will change solutions pH

What are the neutral cations?

Look at these when determining if salt will change solutions pH

Given electon configurations, which has the *smallest* *radius*? What do you look at?

Look at which one has smallest n #! E. has n=2

Find: which e- configuration represents an excited state for an atom?

Look for a subshell that is skipped in a normal ground state config for the largest one Normally it goes 1s 2s 2p 3s 3p 4s *3d* 4p An excited e- skips a shell 1s 2s 2p 3s 3p 4s → 4p

Which of the following conj acid-base pairs would best be used to prepare buffer of pH *3.5*? Given a bunch of Ka values (1.8x10^-4)

Look for weak acid/base + conj pair that has an exponent closest to intended pH 1.8x10^-4 = closest to 3.5

Given 1 volume 2 [M conc] Asked to find final/initial volume

M1V1 = M2V2

Find: rate of effusion Gas A has a molar mass of 4 g/mol and gas B has a molar mass of 36 g/mol. If the gases are at the same temperature, what will be the *rate* of *effusion* of gas B relative to gas A?

MMa = 4g MMb = 36g looking for B/A so invert answer (Grahams law of effusion)

Alkaline earth metals, M, react with oxygen to from a compound with a formula

MO

The larger the molecule, the ____ dispersion forces it has, meaning the _____ the boiling point!

MORE HIGHER

Find:What are some pairs that will react spontaneously?

Make sure redox rxn can occur Use equation Ecell = Ereduction + Eoxidation (+) Ecell = rxn WILL occur (-) Ecell = rxn WONT occur

to calculate neutrons =

Mass - protons

Bonds Describe ionic bonds

Metal + nonmetal high melting point high boiling point brittle hard

Which solids *do* conduct electricity?

Metallic solids

H-bonding only refers to H bonded to what atoms

N, O, F

ammonium

NH₄+

Can strong acids or strong bases form equilibrium reactions?

NO because they dissociate completely!

When calculating molar solubility, there is NO ______ in expression!

NO reactants!!! Because they're a solid and solids and liquids don' t appear in eq. expressions

Do catalysts *shift* equilibrium rxns?

NO, only help rxn reach equalib. more quickly

Which colligative property is used for *high*-molecular weight molecules (1000g/mol or higher)? Why

Osmotic pressure because its easier to accurately measure a small change in osmotic pressure than to measure a tiny difference in freezing/boiling point

Oxidizing agent (oxidants) is _____ To identify an oxidizing agent, its the element that has a:

Oxidizing agent *IS* reduced (needs e-) *positive* oxidation #

Which of the following would most likely be a strong oxidizing agent? reducing agent? A. Alkali metals B. Alkaline earth metals C. Halogens D. Transition metals E. Noble gases

Oxidizing agent: Halogens! Oxidizing agents are *reduced* reduction is *gain* and halogens want to gain +1 e- to feel like closest noble gas! Reducing agent: transition metals are oxidized

Gases density

P*mm/RT

Find: What will increase PCl5? P4(s) + 10Cl2(g) ⇌ 4PCl5(g) + heat A. increase volume B. decreasing temp C adding more P4(s) D. adding inert has E. adding catalyst

P4(s) + 10Cl2(g) ⇌ 4PCl5(g) + heat *B!* decreasing temp A. increasing volume = will shift rxn *left* (toward side w/ *more* gas mol.) B. decrease temp = removing heat (which causes rxn to shift toward *left* which will consequently cause rxn to shift back to the *right* to *increase* PCl5 P4(s) + 10Cl2(g) ⇌ 4PCl5(g) + heat C. P4(s) is a *solid*!!! Which does *NOT* matter in Keq expressions Inert gas or catalyst = never shift eq

Gases Formula for Pressure

P= F/A F=force A=area

Find: Para vs diamagnetic Which of the following would be strongly *attracted* to *magnetic* fields? He H2 Zn O2 N2

Paramagnetic: at least one *unpaired* e- → interact w/ magnetic field Diamagnetic: all e- paired → *won't* interact w/ magnetic field Memorize that O2 = paramagnetic N2 = diamagnetic

Describe relationship between vapor pressure and IMF

Strong IMF stick together, making it harder to boil and leave the liquid as gas, therefore the pressure exerted "up" towards atmosphere is lower than if the IMF were weak and more easily able to escape

What is the only thing that can change the equilibrium constant Keq?

TEMPERATURE!

As far as neutralization rxns are concerned, normality does not depend on strong/weak status T/F

TRUE!!! For calculations involving normality, consider all possible H+/OH- donors H3PO4: n = 3

How do you determine pH from [H+]?

Take *-log* of [H+]

How do you solve for the Kc of the reverse rxn, given the Kc of the forward rxn?

Take reciprocal of forward rxn Kc!

Temperature will affect which one and why? A. Molarity B. Molality

Temp effects *molarity* molarity = mol sub. / vol of solution and increasing temp = increasing volume

Kinetic energy depends *ONLY* on :

Temperature!

Ionization energy

The amount of energy required to remove an electron from an atom

Dalton's Law of Partial Pressures

Total pressure of a gas is equal to the sum of all the gases individual pressures

______ form brightly colored compounds

Transition metals

Find: pH of solution after addition What is the *pH* of a solution prepared by *adding* 20 mL of 0.02 M NaOH(aq) to 20 mL of water?

Use *M1V1=M2V2* to find final volume (+20mL) Used 0.04 L because you are adding 0.02 L of NaOH to 0.02 L of water for total pOH = -log(0.01) = 1.0 x 10^-2 pOH = 2 Plug into pOH + pH = 14

Find: Work done Calculate the *work* *done* by an *ideal* *gas* on its surroundings when the gas is heated at constant pressure of 1 atm from volume 50L to 100L at 298K.

Use question stem to eliminate answers! system →surroundings = (*-*) work (E lost) surroundings → system = (*+*) work (E in system increases) W = PΔV

Liquid Column Chromatography is generally for

differentiate liquids based on *polarity* (uses polar beads)

Molality is used for what 3 colligative properties?

VP BP FP

What is the upward pressure exerted by a liquid substance on the atmosphere?

Vapor pressure

______ acids have small Ka values (10^negative num)

WEAK acids have small Ka values

A liquid with very high volatility is most like to have what characteristic?

Weak IMF (LDF) Can evap easily

HF has a pKa of 3.2 What is the *pH* of a solution comprised of 0.1 M HF and 10 M NaF?

Weak acid + conj base Plug into henderson hasslebach pH = 3.2 + log (10/0.1) 3.2 + log(100) 3.2 + 2 pH = 5

HF has a pKa of 3.2 What is the *pH* of a solution comprised of 0.1 M HF and 0.1 M NaF?

Weak acid + conj. base 1:1 ratio So, pKa = pH pH = 3.2

Raoult's Law tell us: Equation is:

What amount solutions VP decreases when solute is added

Define boiling:

When the vapor pressure *equals* or *exceeds* the atmospheric pressure

Find: energy of photons EX: A certain solar panel has a *work* *function* equal to 2.5 *eV*. If you want the energy of expelled electrons to equal 6 eV, what energy *photons* must strike the solar panel?

When you see photons, eV, expelled, work function this is the *photoelectric* effect ejected *=* photon - work function(Φ)

How do you determine the order of a reaction?

You sum up the coefficients of the reactants (aka the exponents outside the concentration brackets)

Calculate the ΔHrxn for the following C2H5OH + 3O2 → 2CO2 + 3 H20 C2H5OH = -200 CO2 = -400 H2O = -250

Write all the corresponding values underneath each compound. If *one* is missing, check if its an element in its standard state! (O2 = gas) because its ΔH will be 0!

How do you solve for molar solubility?

Write out balanced eq ICE table (set i=1 for solid) Write eq expression (no reactants) Solve for [X] (solubility)

Find: Molar solubility given Ksp and 1 c EX: What is the *molar* *solubility* of BaF2 (Ksp = 1.8×10-7) in 0.10 M sodium fluoride?

Write out dissociation eq Write Ksp expression = [products] Plug in Numbers

How can you tell which salts will change the solutions pH?

Write out dissolved cmpd Cross out any *neutral* cations/anions The charge of the remaining mol will determine pH

How do you calculate the partial pressure of gas given total pressure?

X = Mole fraction (percentage in decimal)

What are the units for the (linear) y-axis of an integrated rate law graph for: zero-order rxn

[concentration]

Quantum numbers What are the 4 quantum numbers and what do they represent?

[n, l, ml, ms] *Principal*: n (period #) (shell) *Azimuthal*: l (subshell) s=0 p=1 d=2 f=3 *Magnetic*: ml (-l -> +l) *Spin*: ms (+/- 1/2)

Equalibrium constant Kc =

[products]/[reactants] coefficients

Keq =

[products]/[reactants] coeff become exponents

Evaporation Is:

transition of liquid to gas @ surface

Parallax error is when

a meniscus in a buret is not observed directly straight on

What is an intensive property? Examples?

a property of solutions that only depends on ratio of solute to solvent particles, NOT what *type* of particles they are Density Pressure Temperature

Amphoteric is

a substance that can act as both an acid and a base Ex: H2O

To be a meso compound, it needs to have what 2 things

at least: 1 chiral center 1 plane of symmetry

Ideal gas constant (R) for pressure in *atm*

atm = 0.082

What keeps molecules in liquid from escaping?

atmospheric pressure (downward pressure exerted by atmosphere)

Atomic weight vs mass #?

atomic weight = sum of all isotopes atomic masses * abundances Mass number = protons + neutrons

Law of conservation of mass

atoms cannot be created nor destroyed This is why we balance chemical equations!

Isotopes are

atoms of the same element with different atomic masses

Atomic masses are actually the

average of isotope forms

Technique to separate compound by solubility in solvent (polarity) a. distillation b. thin layer chromatography c. Recrystallization d. gas-liquid chromatography

b. TLC

Metal-oxides + water --> ________ solutions

basic

Why does water have a negative solid-liquid line of equilibrium slope?

because it's denser as a liquid than as a solid! (cuz of bent shape of water)

3 domains 1 lone pair

bent 120

The most neutralizing base will be the one with the

biggest (*-*) charge cause it can react w more equiv of acid to neutralize

Find: boiling point What is the boiling point of a solution of 5.0 mol of glucose dissolved in 1000 mL water? (Kb for water = 0.512°C / m; assume density of water = 1g/mL)

boiling point elevation= = (k)(i)(m) m = molality (mol/kg) k = Kb = 0.512°C i = 1 = 2.56 elevation SO, now *add* 2.56 to boiling point of water (100°C) 100 + 2.56 = 102.6°C

a device that doesn't let heat in or out and burns (combusts) the substance to see how much heat it releases

bomb calorimeter q = -CΔT

The enthalpy of a reaction is related to its

bond energy! ΔH = bonds broken *-* bonds formed reac - prod

ΔH = bonds broken - bonds formed

bonds broken = reactants bonds formed = products

What type of apparatus would you use for a titration?

burette

Rank species in order of increasing size - If its an isoelectronic species (they all have same # e-), how do you sort them?

by *#* of *protons*!! More protons = smaller size Less protons = bigger size (Zeff)

_______ are highly reactive w metals, and thus, good oxidizing agents a. noble gasses b. transition metals c. halogens d. non metals

c. halogens

What technique dissolves an impure compound in hot solvent and gradually precipitates the pure compound as the solution cools down? a. fractional distillation b. distillation c. recrystallization d. extraction

c. recrystallization

The solvation of ionic compounds in water is due to which of the following? a. reactions with OH- and H3O+ b. diffusion c. dipoles of water d. high specific heat of water e. cohesive and adhesive forces

c. waters dipoles help draw out the + and - charges in ionic compounds

____ is a technique that measure the rxns heat transfer

calorimetry

_________ occurs when the adhesion to the walls is stronger than the cohesive forces between the liquid molecules.

capillary action

In *electrolytic* cells, cations flow towards _____ to get _____ anions flow towards ___ to get ___

cathode, reduced anode, oxidized

Metals are defined as

cations held together by a sea of e-

Dont forget, when using Ecell equation, you have to :

change the sign (+ or -) of the standard reductio potential in the table for the *oxidation* rxn

What is oxidation number in monatomic ions (K+, S2-, Mg2+, Al3+)

charge of the ion

THe law of conservation of charge states

charges cannot be created nor destroyed, only transferred

A compound can only be separated by ____ means

chemical (rxns)

what is an electrolyte? Which cmpds are usually electrolytes?

cmpd that dissolves and separates into ions in water ionic cmpds! (nonmetal+metal) (NaCl)

Under standard conditions, ____ can be completely ignored when using Ecell equation

coefficients!

What is an issue with *aqueous* electrolysis?

competing H20 rxn Use table of reduction pot. to find which one will happen more easily

Technique that separates components in liquid mixture by *boiling* *point* a. distillation b. thin layer chromatography c. Recrystallization d. gas-liquid chromatography

d. gas liquid chromatography *lowest* bp comes off fastest!!

Gas to solid

deposition, exothermic

Titrations are used to

determine the *conc* of an unknown acid or base

In a rxn coordinate diagram, what is delta H?

difference between energy levels of reactants and products -H = exothermic

A compound is non-aromatic if it fails either of what 2 criteria

fails either 1. cyclic 2. no sp3

Find: What is the strongest *oxidizing* agent?

find sub. with the highest (most +) red potential from table correct answer is the *metal*, not ion! (Al, not Al3+)

Find: What is the strongest *reducing* agent?

find sub. with the lowest (most -) red potential from table correct answer is the *metal*, not ion! (Ni, not Ni2+)

Find: how much *energy* is required to do some stuff EX: How much *energy* is required to increase the *temp* of 36.0 g of H2O from -20 °C to 50 °C, keeping in mind the following: Cice = 2 J/g*C Cliquid water = 4 J/g*C ΔHfusion = 6000 J/mol

first, notice answer units will be J or kJ because its asking about amount of *energy* Now draw out energy diagram to keep track of values q = mcΔT

Ideal gas constant (R)

for atm R=0.0821 L*atm/mol*K for kPa R = 8.314

Solid to liquid

fusion/melting

A concentration cell is a type of ____ cell. What drives the current in a conc. cell?

galvanic tendency for 2 differing conc to equalize due to *entropy*

Units for a zero order reaction

m/s

Calculate # of neutrons?

mass number - atomic number (# protons)

Measure a gas's pressure using a ___

mercury (Hg) manometer

Ionic solids are made up of

metal + nonmetal

Metallic solids are made up of

metal+metal

Find: mol fraction EX: 1 mol of HNO3 is dissolved in 54.0 grams of H2O. What is the mole fraction of HNO3?

mol *X* / total mols

What determines whether substance is solid, liquid or gas at given T and P?

mol. IMF!!!

Molality =

moles of solute/kg of solvent

Molarity=

moles of solute/liters of solution

In a titration, an equivalence point is

moles of strong base = moles of strong acid

Under ____, there is *no* saltbridge

molten electrolysis

Describe successive ionization energies

once you remove all the valence e-, ionization energy increases ALOT

Monoprotic acids have

one H+ per molecule

Formula for osmotic pressure

op = iMRT (#ions)(molarity)(R)(temp in K) R in atm = 0.082 R in kPa = 8.314

What's the difference between column chromatography and TLC spots?

opposites!

If solution goes from (solid -----> gas, What change in entropy will be seen?

order -----> disorder *(+ΔS)*

Eluent:

organic (nonpolar) solvent used in column chromatography

When a question asks, how many e- are transferred in this reaction, what do you look at?

oxidation numbers!

Metals form basic ____

oxides

_____ likes to react w metals to form metal oxides

oxygen (O2 & O3) O3 is better

Given pOH, what is formula for calculating pH? Formula for calculating [H+]?

pH + pOH = 14 or 10^-(14-pOH)

pH =

pH = -log[H+]

When there is the same [conc] of weak acid/conj base is the *same*, pH =

pH = pKa

Henderson-Hasselbalch equation

pH = pKa + log [A-]/[HA]

How do you find pKa given Ka? What if Ka= 1.8x10^-4

pKa = exponent of Ka since 1.8 is *more* than one, the pKa will be slightly *less* than exponent pKa = > 4

Paramagnetic vs diamagnetic If an element has an *ODD* number of e-, then its __________

paramagnetic- unpaired e- and *attracted* to magnets diamagnetic- no unpaired e- *repelled* by magnets ODD = paramagnetic

T/F Catalysts may be classified as either homogenous or heterogenous

true! Homogenous = if catalyst is in *same* phase (s,l,g) as reactant Heterogenous = if catalyst is in *diff* phase than reactant

What is lattice energy? larger charges = _________ lattice energy

the energy required to completely separate an ionic cmpds cations (+) from its anions (-) larger!

What always occurs during a spontaneous reaction?

the entropy of the *universe* will always increase (2nd law of thermo)

When given ionization energies and trying to determine which element it is, look at

trend in energies EX: 738 → 1st 1451 → 2nd 7733 → 3rd notice that the *3rd* is the biggest! meaning it has to be a column 2 element because once it looses its second e-, it feels like noble gas, and to remove an electron from that is an *extremely* large number

For common ion questions, the common ion feeds back into which equation?

the one with the solid!

Solubility depends on

the polarity of molecule

5 domains 0 lone pairs

trigonal bipyramidal 90,120

3 domains 0 lone pairs

trigonal planar 120

4 domains 1 lone pair

trigonal pyramidal <109.5

Dynamic equilibrium means

the speed of forward & reverse rxns is the same

When comparing acids, K>1 value means that the stronger acid will be on what side of the rxn?

the stronger acid will be on reactant side, meaning theyre product favored

Transition metals form colorful compounds due to : These are found where on the periodic table?

the way their d- orbitals behave d-block

Can dispersion forces occur within individual atoms?

yes!

What is oxidation number in uncharged elements bonded to other elements (H2, Na, Cl2, Al)

zero

The relationship between ΔG and K is given by which equation

ΔG = -RTln(K) ΔG and K = inversely related

Calculating half reactions Calculate ΔH value of overall reaction by mathematically manipulating and then combining the: What are the rules?

ΔH of it's *half-reactions* 1. if rxn flipped around, reverse sign of ΔH 2. if you mulitply rxn by number, also multiply ΔH by that # 3. When u add rxns together, add their ΔH 's

The enthalpy of formation is ΔH =

ΔH of the chemical rxn of forming *one* mol of a single substance from its parent elements, at 289K (25C) and 1 atm -ΔH = exothermic +ΔH = endothermic

A change in entropy is spontaneous if

ΔS(surround) + ΔS(system) > 0 +ΔS = spontaneous & exer -ΔS = non-spon

Boiling-point *elevation* equation

ΔTb=(K)(i)(m) ΔTb = *change* in waters bp(from 100C) K = boiling point constant i = # of ions when dissolved m = solutions molality

What is the Gibbs free energy equation?

∆G = ∆H - T∆S

Find: Number of ions each solution will produce EX: Two separate solutions are created. One using water and *KCl*, and the other using water and *CaCl2*. Assuming the molality is equal in both solutions. Which will have higher bp? Which will have higher freezing point?

∆Tb = (K)(i)(m) since everything else is equal, just focus on (i) for each = how many ions each solution will form *KCl* = 2 ions *CaCl2* = 3 ions Higher bp & lower freezing point = CaCl2 (farther range) Lower bp & higher freezing point = KCl (closer range)