AP Chemistry every single unit

The (blank) of a system is a measure of the randomness or dispersion of the system

Entropy or S

The greater the (blank), the greats its entropy

dispersion of a system

Zero entropy is defined as a (blank) at (blank)

• Solid Crystal

• 0 K

All substances that we encounter will have some (blank) value for entropy

positive

The standard entropy change is (blank)

ΔS

The difference between the standard Entropies of products and reactants

S_products - S_reactants

How to predict the sign of ΔS

• Solids are less dispersed than liquids

• if some of the matter is gas you should assume its positive

• if a solid is the only product, there is a negative value

• an aqueous solution is more dispersed than an organized precipitate

• If there are more ions in the reactants, then it will be negative

Gibbs free energy determines (blank)

whether that process is thermodynamically favored or unfavored

Favored or unfavored could also mean (blank)

• spontaneous

• nonspantaneously

How to find ΔG equation

G_products - G_reactants

If G is negative the reaction is (blank)

thermodynamically favored

If G is positive the reaction is (blank)

thermodynamically unfavored

If G is 0 the reaction is (blank)

At equilibrium

Thermodynamically favored processes must result in (blank) or (blank) or (blank)

• decreasing enthalpy

• increasing entropy

• both

Equation that relations favorability, enthalpy and entropy

ΔG = ΔH - TΔS

Negative ΔH, Positive ΔS, at Low and High T, and negative ΔG result in (blank)

always favored

Positive ΔH, negative ΔS, at Low and High T, and positive ΔG result in (blank)

Never favored

Positive ΔH, Positive ΔS, Low and High T, and positive ΔG result in (blank)

• Not favored at low temps

• favored at high temps

negative ΔH, negative ΔS, Low and High T, and negative ΔG result in (blank)

• favored at low temps

• not favored at high temps

A substance at a normal phase transition temperature is equally (blank) in either of those two phases. As a result (blank) at that temperature

• stable

• ΔG = 0

Standard Free Energy Change and the Equilibrium Constant equation

ΔG = -RT

Every half reaction has a (blank) associated with it

voltage

Potential Constant

E

The larger the potential for a half-reaction, the more (blank)

likely it is to occur

Two things to consider when calculating the potential of a redox reaction

1. Add the potential for the oxidation to the potential for the reduction

2. never multiply the potential for a half reaction a coefficiet

Galvanic cell is a (blank)

favored redox reaction that is used to generate a flow of current

Current is defined at the (blank)

as the flow of electrons from one place to another

Oxidation takes place at the electrode called the (blank)

Anode

Reduction takes place at the (blank)

Cathode

At the cathode, the solution becomes (blank) and the (blank) from the salt bridge solution flow into the half cell

• less positively charged

• positive cations

At the anode, where oxidation occurs the solution is becoming more (blank) and the (blank) from the salt bridge solution flow into the half-cell

• more positively charger

• negative anions

Under standard conditions, the voltage of the cell is the (blank) as the total voltage of the (blank)

• same

• redox reaction

Standard conditions for voltaic cells is (blank)

25 C, 1.0 atm and a concentration of 1.0 M

• Any deviation will result in the cell potential also deviating

Voltaic cells are are very (blank) having equilibrium constants greater than (blank)

• favored

• 1

If Q for a voltaic cell becomes equal to the equilibrium constant, the voltage becomes (blank)

zero

To determine if a cell’s potential will change if the standard condition is deviated to use (blank)

The reaction Quotient

The reaction quotient will equal to 1 unless (blank) which would cause the Q to become closer to the equilibrium constant therefore making it (blank)

• increase in concentration of a product, or decrease in reacts

• decrease

(blank) can also affect the Q and a change in (blank)

• Pressue

• Temperature

An outside source of voltage is used to (blank) redox reactions to take place

force an unfavored

the anode and cathode are usually just (blank)

metal bars that conduct currents

The sign of you total cell potential (E) should always be (blank)

negative

When a current will run through a molten compound or pure water, you do not have determine redox reactions because (blank)

There will only be one choice for each

Electrolytic cells are used for (blank)

electroplating

Four steps to figure out electrolysis probelms

1. Calculate the charge in coulombs

2. you now know the amount of electrons

3. when you find the moles of electrons you know the half-reaction

4. once you know the moles of metal, you can calculate the number of grams

A redox reaction will be favored if (blank)

its potential has a postive valuei

A reaction that is favored has a (blank) for (blank)

• negative value

• free energy change

Equation for reaction potential and free energy for a redox reaction

ΔG = -nFE

If E is positive, G is (blank) and the reaction is (blank)

• negative

• favored

If E is negative, G is (blank) and the reaction is (blank)

• positive

• unfavored

The autoionization of water (blank) to dissociate

• reacts with itself

The equilibrium expression for the autoionization of water is (blank)

[H⁺][OH^-] = 1.0 × 10^-14 at 25 C

Acid Dissociation Constant

[H⁺][A^-] / [HA]

Base Dissociation Constant

[OH^-][HA] / [A^-]

How to convert K_a or K_b to pK_x

pKx = -logKx

Stronger acids and bases both (blank) to a greater extent in water

Dissociate

Stronger acids have higher values of (blank) and lower values of (blank)

• Ka

• Pka

Strongers acids or base have weaker (blank)

conjugate bases or acids

Strong acids will completely (blank) in water

dissociate

Strong Acids

HCl, Hbr, HI, HNO3,H2SO4, HClO4

Strong Bases

Group 1 hyrdoxides, LiOH, NaOH, KOH, BaOH2, SrOH2

Weak acids only (blank) dissociate in water

partially

Most of the acid molecules of a weak base will remain in the solution as (blank)

undissociated aqueous particle

pH and pOH are measures of the (blank) or (blank) or nature of a solution which depends on the (blank)

• acidic

• basic

• concentration

Acidic solutions have (blank) solutions and (blank)

• higher concentration

• lower pH

Less acidic solutions have (blank) and (blank)

• lower concentration

• higher pH

(blank) is what percent of an acid or base’s initial concentration dissociates in aqueous solutions

Percent dissociation

Auto-ionization of water is an (blank process)

Endothermic

Kw will increase at a higher (blank) and this increases concentration of (blank) and decrease both (blank)

• concentration

• H and OH

• pH and pOH

as pH increases so does the (blank)

Concentration of OH

as pH decreases, (blank) increases

Concentration H3O

Basic salts are less soluble in (blank) solutions than in (blank) or neutral

• Basic

• Acidic

Acidic salts are less soluble in (blank) solutions than in basic or neutral ones

acidic

Some acids can donate more than one H⁺ these are called (blank)

Polyprotic acids and bases

When an acid gains another negative which (blank) remaining protons more (blank)

• attracts

• strongly

OH is referred to as the (blank) group

Hydroxyl

CO2H group is (blank)

Carboxylic acids

conjugate bases have (blank) charges so structural features help (blank) which weakens the bond to (blank) and makes the compound more (blank)

• negative

• stabilize

• dissociate H⁺

• acidic

Electronegative atoms tend to (blank) a negative charge, which is why (blank) group is acidic

• stabilize

• Hydroxyl

(blank) is also important. The negative charge in (blank) group gets highly stabilized. Also the reasoning behind why this group is (blank)

• Ressonace

• Carboxylic

• acidic

Many bases are of (blank) group. They contain basic (blank) and are called (blank)

• Nitrogenous

• NH2 group

• amines

Carboxylates, conjugates of weak acids are also weakly (blank)

basic

Neutralization reaction and their four mechanisms

1. Strong Acid + Strong Base

2. Strong Acid + Weak Base

3. Weak Acid + Strong Base

4. Weak Acid + Weak Base

A (blank) is a solution that resists changes in pH when small amounts of acids or bases are added

Buffer

The pH of a buffer will also remain unchanged if the solution is (blank)

diluted with water

A buffer is created by placing a large amount of a (blank) into solution along with its (blank) in the form of salt

• weak acid or base

• conjugate

A weak acid and it’s conjugate base will remain in (blank) with one another rather than completely neutralizing

equilibirum

If some strong acid was added, the extra H+ would cause the system to shift (blank)

left

If a strong base was added, it would react with the H+ and shift to the (blank)

right

Strong Acids and Strong Bases can’t be used for buffers because their conjugates are essentially (blank)

Non-reactive

Henderson-Haselbalch Equation

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

If enough external acid or base is added, the components of the buffer will be (blank) and no longer function as a buffer

depleted

if you start at pH = pKa and add more HA so the (blank) because (blank)

• pH will decrease

• pH < pKa and HA>A

pH will decreases if you add more (blank) because (blank)

• A

• HA < A and pH > pKa

(blank) are weak acids that change color in certain pH ranges due to (blank)

• Indicators

• Le Chateliers Principle

The protonated Hln state has to be a different (blank) than the deprotonated ln state

color

When the indicator is present, and the environment is acidic, the excess H+ drive the (blank) causing the solutions to mainly consist of (blank)

• equilibirum left

• Hln

In a basic environment, the excess OH ions react with the H+ from the indicator and shift the reaction to the (blank) causing the solution to consist of (blank)

• right

• ln

The indicator will experience a color shift when (blank) and the two values cancel out, which leaves the expression (blank)

• Hln and ln are present in equal amounts

• Ka = [H+]

(blank) is when the moles of titrant added are equal to the moles of analyte

Equivalence point

(blank) is when the concentration of the acid is equal to the conjugate base, as well as the (blank)

• Half Equivalence point

• pH = pKa