Chem 105 Final R

Front 1

Define Gas

Back 1

A state of matter that:
1) fills any container it occupies
2) is highly compressible
3) always forms homogenous mixtures when mixed with other gases
ex: O2 (diatomic), Ar (monotomic), propane, steam, radon

Front 2

Define Vapour

Back 2

A gas, sometimes meant to be a gas that isn't normally a gas
ex: water vapour, acetic acid vapour

Front 3

Define Pressure

Back 3

The force per unit area acting on an object
P=F/A
SI unit: Pa

Front 4

What is the Ideal Gas Equation?

Back 4

PV=nRT
This is for gases only!

Front 5

What is the gas constant?

Back 5

R
0.08206 Latm/molK
8.314 m^3Pa/molK
8.314 J/molK

Front 6

What are the STP conditions?

Back 6

T = 273.15 K
P = 1 atm

Front 7

Define Solution

Back 7

A homogeneous mixture of compounds

Front 8

What is not a solution?

Back 8

- Pure compounds (pure water)
- Heterogeneous mixtures (margueritas)
- Colloids (milk)

Front 9

Why do solutions form?

Back 9

The formation of solutions is driven by the natural tendency for disorder in the universe (second law of thermodynamics)

Front 10

What is the effect of enthalpic penalty?

Back 10

There may be an enthalpic penalty for mixing which may prevent formation of solution. Mixing nonpolar compounds with ions or polar compounds. An enthalpic penalty exists if dissolving A in B is endothermic
"like dissolves like"

Front 11

Define Solubility

Back 11

The max amount of the solute that can dissolve in a given amount of solvent at a specified T and P

Front 12

What is a saturated solution?

Back 12

If the solubility of a compound is x g/100 mL and x g is dissolved in 100 mL, the solution is saturated

Front 13

What is an unsaturated solution?

Back 13

If the solubility of a compound is x g/100 mL and less than x g is dissolved in 100 mL, the solution is unsaturated

Front 14

What is a supersaturated solution?

Back 14

If the solubility of a compound is x g/100 mL and more than x g is dissolved in 100 mL, the solution is supersaturated.
- This solution is unstable and will form a precipitate

Front 15

How are supersaturated solutions formed?

Back 15

Formed by chilling a solution that was saturated at a different temperature

Front 16

What is the effect of the nature of solute and solvent on solubility?

Back 16

Solubility increases as attractions between solute and solvent increase (increases with more electrons)
"like dissolves like"

Front 17

What is the effect of pressure on solubility?

Back 17

Gas solubility increases as pressure increases
- Solid solubility is unaffected by P

Front 18

What is the effect of temperature on solubility?

Back 18

Gas solubility decreases as temperature increases
- Solid solubility increases as temperature increases

Front 19

What is the equation for % by mass?

Back 19

% by mass = msolute/msolutions x 100%

Front 20

What is the equation for ppm?

Back 20

ppm = msolute/msolution x 10^6 ppm

Front 21

What is the equation for mole fraction?

Back 21

Mole fractionxsolute = nsolute/nsolution

Front 22

What is the equation for molarity?

Back 22

Msolute = nsolute/Vsolution (mol/L = M)

Front 23

What is the equation for molality?

Back 23

msolute = nsolute/msolvent (mol/kg = m)

Front 24

Define Chemical Equilibrium

Back 24

A situation in which a forward and reverse chemical reaction occur at the same rate, in which case the [ ]'s of each reactants and products are each unchanging (constant) vs. time

Front 25

What is the equilibrium constant?

Back 25

Kc= [C]^c [D]^d / [A]^a [B]^b
- only for gas and aqueous phases

Front 26

What is the conversion from Kc to Kp?

Back 26

Kp = Kc(RT)^delta n

delta n = nf - ni (change in stoichiometry of the forward reaction

Front 27

What is Le Chatelier's Principle?

Back 27

If a system at equilibrium is disturbed by a change in T, Ptotal, or a component [ ], the system will shift its "equilibrium" position so as to counteract the effect of the disturbance

Front 28

What is the [ ] effect on Le Chatelier's Principle?

Back 28

If more reactant is added, the system counteracts this by consuming part of the excess. This means that the equilibrium shifts to the right
- ie. [ ] decreases for reactants and increases for products

Front 29

What is the pressure effect on Le Chatelier's Principle?

Back 29

If pressure is increased (by decreasing V), the system counteracts this by reducing the number of moles of gas
ex: What happens to the equilibrium (of a rxn) if the vessel volume is reduced?
- The reverse rxn reduces number of moles of gas

Front 30

What is the temperature effect on Le Chatelier's Principle?

Back 30

If the temp is increased, the system counteracts this by shifting forward in the endo direction to consume excess heat

Front 31

What is the Bronsted-Lawry definition of an acid?

Back 31

A substance that donates H+ to another substance
ex: HCl

Front 32

What is the Bronsted-Lawry definition of a base?

Back 32

A substance that accepts H+ from another substance
ex: NH3

Front 33

What are amphiprotic compounds?

Back 33

Compounds which could be either acids or bases
ex: H2O, HCO3-. HSO4-

Front 34

Define Conjugate Acid (of a base)

Back 34

The protonated base
ex: H3PO4 is the c.a. of H2PO4-
H3O+ is the c.a. of H2O

Front 35

Define Conjugate base (of an acid)

Back 35

The deprotonated acid
ex: H2PO4- is the c.b. H3PO4
OH- is the c.b. of H2O
So42- is the c.b. of HSO4-

Front 36

What are strong acids and bases?

Back 36

Strong H+ donating/accepting potential
- As a general rule, the stronger the acid, the weaker the c.b. and the stronger the base the weaker the c.a.

Front 37

What is the autoionization of water?

Back 37

Kw = [H+][OH-] = 1.0 x 10 ^-14 at 25C

Front 38

What is the pH Equation?

Back 38

pH = -log[H+]

[H+] = 10^-pH

Front 39

What is the equation for pOH?

Back 39

pOH = -log[OH-]

[OH-] = 10^-pOH

Front 40

How are pOH and pH related?

Back 40

pH + pOH = 14.00

at 25C

Front 41

What is used to measure pH?

Back 41

- A pH meter, uses voltage readings
- pH indicators, litmus paper, dye drops

Front 42

Give some examples of strong acids

Back 42

HCl, HBr, HI, HNO3, HClO4

Front 43

Give some examples of strong bases

Back 43

NaOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

Front 44

What is common between strong acids and bases?

Back 44

100% ionize (dissociate) in water

Front 45

What is the acid dissociation constant?

Back 45

Ka = [H+] [A-] / [HA]

- Denotes how strong or weak the acid is

Front 46

What is the equation for % Ionization?

Back 46

[H+]equil / [HA]init x 100%

Front 47

What is the base dissociation constant?

Back 47

Kb = [HB+][OH-] / [B]

Front 48

What is the relationship between Ka and Kb?

Back 48

KaKb = Kw

Front 49

What are binary acids?

Back 49

HnX
ex: HBr, H2S, H2PO

Front 50

What are oxyacids?

Back 50

HnYOm
ex: H2SO4, HNO3, HOCl

Front 51

Since oxyacids seem to have OH groups, why aren't they bases like NaOH?

Back 51

Because in oxyacids, the Y atom is fairly EN, and makes a strong covalent bond with O

In a hydroxide base like NaOh, the Y atom can only form a weak ionic bond with O

Front 52

Define Lewis Acid

Back 52

An electron pair acceptor
- Includes high-charged metal atoms like M2+ and M3+ and boron compounds

Front 53

Define Lewis Base

Back 53

An electron pair donor

Front 54

What is the common ion effect?

Back 54

Whenever a weak electrolyte and a strong electrolyte containing a common ion are together in solution, the weak electrolyte ionizes less than it would if it were alone in solution
- An existing common ion will reduce the solubility of a new salt

Front 55

What are buffers?

Back 55

Solutions whose pH can stay somewhat constant even if small amounts of strong acid or strong base are added. This tends to happen with solutions of weak acids and weak bases

Front 56

Give some examples of some solutions where buffers will work

Back 56

CH3COOH/CH3COO- yes
NH4+/NH3 yes
HCO3-/CO32- yes
HNO2/NO3- NO

Front 57

Why do buffers work?

Back 57

1) Added H+ is converted to HA (or HA+) by weak base A- (or A)
2) Added OH- is converted to H2O by weak acid HA

Front 58

What is the Henderson-Hasselbalch Equation?

Back 58

pH = pKa + log ([c.base]/[acid])

pKa = -logKa

Front 59

What is Titration?

Back 59

The determination of a concentration C1 by reacting it with a solution of known [ ] C2 until an equivalence point is reached
ex: adding NaOH(aq) to acid Hx(aq) --> H2O + NaX (aq)

Front 60

What is the solubility product constant?

Back 60

Ksp

Front 61

Define solubility

Back 61

The max mass of solute that can dissolve in a given volume of solvent at a specified temp

Front 62

How are S and Ksp related?

Back 62

- Low Ksp means low S
- S depends on presence of other ions, Ksp does not

Front 63

What effect does pH have on S?

Back 63

- Increasing solution acidity will increase the S of a salt with a basic anion
ex: NaCN
- Increasing solution basicity will increase the S of a salt with an acidic cation
ex: C4Cl2

Front 64

What can increasing acidity do?

Back 64

Can erode slightly soluble ionic solids
ex: sea coral, tooth enamel

Front 65

Define thermodynamics

Back 65

The study of transformations of E

Front 66

What is the first law of thermodynamics?

Back 66

E can never be created no destroyed

Front 67

Define spontaneous process

Back 67

One that would naturally occur without work being required
- All chemical rxns have a spontaneous direction unless they are at equilibrium

Front 68

What is a reversible process?

Back 68

An idealized one that takes a system from state A to B via small changes that could be reversed
- Such a process would produce the max amount of work from A to B
- Real processes are irreversible

Front 69

What determines the spontaneous direction?

Back 69

The spon direction is the direction of change that leads to more disorderly dispersal of the total E of the universe

Front 70

Define entropy (s)

Back 70

The degree of disorder or randomness of E dispersion

Front 71

How are vibrational, rotational and translational motion related?

Back 71

Vibrational motion is more ordered (less microstate options) than rotational motion, which is more ordered that translational motion

Front 72

Define electrochemistry

Back 72

The study of the relationships between chemical rxn and electrical work (electricity)

Front 73

Define oxidation

Back 73

Loss of electrons

Front 74

Define reduction

Back 74

Gain of electrons

Front 75

Define redox (oxidation-reduction) reaction

Back 75

A transfer of electrons from one reactant (the one oxidized) to the reactant being reduced

Front 76

Define voltaic cell (Galvanic cell)

Back 76

A device that uses spon redox rxns to do electrical work
ex: generate electricity through a wire

Front 77

Define anode

Back 77

Electrode where oxidation occurs, losing electrons to the wire.
- Negative

Front 78

Define cathode

Back 78

Electrode where reduction occurs, gaining electrons form the wire
- Positive

Front 79

Are voltages intrinsic properties?

Back 79

Yes, halving or doubling the half reaction stoichiometry does NOT alter the voltage

Front 80

Define battery

Back 80

A self-contained voltaic cell (or several in a series) but without the connecting wire

Front 81

Define liquid

Back 81

- A phase of matter which assumes the shape of the container it occupies
- Does NOT expand to fill its container
- Is virtually incompressible
- Flows readily
- Diffusion within a liquid occurs readily

Front 82

Define dipole-dipole forces

Back 82

Electrostatic attraction of opposite ends of polar molecules
ex: HCl

Front 83

Define dispersion forces

Back 83

Instantaneous-dipole-to-induced-dipole electrostatic attraction
ex: N2

Front 84

Define H-bonding

Back 84

Strong dipole-dipole electrostatic attraction due to extreme polarity of N-H, O-H and F-H bonds, and the ability of tiny H atoms to get close to other lone pairs of electrons
ex: H2O

Front 85

Define viscosity

Back 85

The resistance of a fluid to flow (stress)
- Informally, how "thick" a liquid behaves
- Increases with increasing amounts of intermolecular forces
- Increase in T decreases viscosity

Front 86

Define surface tension

Back 86

The resistance of a liquid surface to increase its surface area
- Increases with increasing amounts of intermolecular forces
- Increase in T decreases surface tension

Front 87

Define metals

Back 87

Solids of elements so weakly electronegative that their valence electrons roam throughout the atomic lattice (hence high electron conductivity)

Front 88

Define amorphous solids

Back 88

Disordered

Front 89

Define crystalline solids

Back 89

Ordered with unit cells

Front 90

Define unit cell

Back 90

The smallest repeating structural unit

Front 91

What are metals?

Back 91

- Crystalline
- Shiny
- Feel cold (high thermal conductivity: heat spreads rapidly)
- Have high electrical conductivity
- Are malleable
- Are ductile

Front 92

Define alloy

Back 92

A metal containing more than one element
ex: Bronze, 88% Cu, 12% Sn

Front 93

Define substitutional alloy

Back 93

1-phase "solid solution" of similar sized atoms
ex: AuxAgy

Front 94

Define interstitial alloy

Back 94

1-phase "solid solution" of extreme-size atoms
ex: FexCy

Front 95

Define heterogeneous alloy

Back 95

2-phase "not quite solution" mixtures
ex: Fex(Fe3C)y

Front 96

Define Intermetallic compound alloy

Back 96

1-phase fixed-ratio compound
ex: Ni3Al

Front 97

Define polymer

Back 97

A covalent-network solid made by covalently linking small molecules ("monomers") in a repeating fashion

Front 98

Give some examples of natural polymers

Back 98

Wool, leather, silk, natural rubber, cellulose

Front 99

Give some examples of synthetic polymers

Back 99

Plastics (moldable synthetic polymer)
- Ethene - Polyethylene
- Propene - polypropylene
- Vinyl chloride - PVC

Front 100

Define nuclear chemistry

Back 100

The study of nuclear rxns which change atoms into other atoms via changes in atomic nuclei