CHM F Exam 2

Types of Reactions, Electron Behavior, Waves

Strong Acids

HCl, HBr, HI, HClO4, HNO3, H2SO4

Strong Bases

G1 and G2 hydroxides

Non-electrolytes

H2O, CH3OH (methyl alcohol), C2H5OH (ethyl alcohol), C12H22O11 (sucrose), most carbon compounds, covalent molecules

What makes acids/bases strong electrolytes?

they dissociate completely in solution

• they are good conductors

What makes acids/bases weak electrolytes?

they only partially dissociate in solution

• weak conductors

What makes things nonelectrolytes?

don’t dissociate at all in solution

• are poor conductors

molarity (M) =

moles (n)/ volume (v)

ions carry _____

electrons

• which is why strong electrolytes are good conductors

Arrhenius Definition of Acids and Bases

acid: makes protons in solution

base: makes hydroxide ions in solution

Bronsted-Lowry Definition of Acids and Bases

acid: makes protons in solution

base: accepts protons in solution

Lewis Definition of Acids and Bases

acid: accepts e-

base: donates e-

strong acids make higher [__] in solution

[H+]

strong bases make higher [___] in solution

[OH-]

monoprotic acids

have 1 H+

diprotic acids

have 2 H+

tri-protic acids

have 3 H+

pH scale

0-14

<7: acidic

7: neutral (deionized water)

>7: basic

Higher pH =

stronger base

Lower pH =

stronger acid

HI

hydroiodic acid

HClO4

perchloric acid

H2SO4

sulfuric acid

HBr

hydrobromic acid

HCl

hydrochloric acid

HNO3

nitric acid

H3PO4

phosphoric acid

HF

hydroflouric acid

HNO2

nitrous acid

CH3CO2H

acetic acid

H2SO3

sulfurous acid

HClO

hypochlorous acid

HClO2

chlorous acid

HClO3

chloric acid

neutralization reactions

acid + base = salt + H2O (l)

A: initial acid conc

B: buffer region ([acid]=[con base]

C: equivalence point [acid]=[base]

above C: end point

D:excess base present

graph with strong acid + strong base

point C (equivalence point) has pH of 7

graph with strong acid + weak base

point C (equivalence point) has pH of <7

graph with weak acid + strong base

point C (equivalence point) has pH of >7

Phenophthalein

indicator that turns pink in basic solution (so OH- ions are present)

Electronegativity

the tendency of an atom to attract electrons

• increases up a group and across a period

Oxidation # equals ______ in any neutral substance that contains atoms of only one element (O2)

0

Ox # equals ________ for ions that contain only one atom

the charge of the ion

Ox # of hydrogen is ____ when combined with a more electronegative element

+1

Ox # of hydrogen is ____ when combined with a less electronegative element

-1

Ox # of G1 and G2 are ____ and _____ respectively

+1 and +2

Ox # of oxygen is usually _____ unless it contains a single O-O bond, where it could be ____ (O2, O2-2, O3)

-2

-1

Ox # of G7 is usually ___ when bound to a less electronegative element

-1

the sum of oxidation numbers for atoms in a neutral molecule is equal to ____

0

the sum of oxidation numbers in a polyatomic ion is equal to ______

the charge of the ion

the least electronegative atom in a molecule has a ______ oxidation number

positive

the most positive oxidation number for an atom is often equal to _____

its group number

the most negative oxidation number for a nonmetal is calculated by _______

8- group #

Redox rxns

red: when the ox # of an atom becomes more negative/decr

ox: when the ox # of an atom becomes more positive/incr

reducing agents

does oxidation (gives e- to something else)

oxidizing agents

does reduction (receives the e-)

m1v1=

m2v2

• molarity and volume of dilutions

ka of strong acids

»»1

ka of weak acids

««1

kb of strong bases

»»1

kb of weak bases

««1

electrons behave as both _____ and _____

particles and waves

wavelength (λ)

the distance between two successive wave peaks

frequency (v)

the number of wave peaks that pass a given point per unit of time

trough

the bottom part of a wave

peak/crest

the top of a wave

amplitude

the height of a wave from maximum to the center

as λ incr,

v decr

as amplitude incr,

energy/intensity incr

gamma rays

can change how your DNA is wired, potentially causing cancer

is you can see red, it means that

green is absorbed and red is being reflected

humans can see between the wavelengths of

400-800 nm

λ x v =

c

c

3.00 e8 m/s

• speed of light

E=

h x v

h

6.626 e-34 J*s

• Planck’s constant

work function

energy required to reject an e- from an atom of an element

diff freq =

diff energy

Bohr’s model of the atom only explains

hydrogen

closer to the nucleus =

more energy

electrons in a hydrogen atom travel

around the nucleus in a circular orbit

the energy of an electron in a given orbit is proportional to

its distance from the nucleus

it requires energy to move ____ and energy level

up

Can an e- be between energy levels?

NO

only orbits with certain

energies are allowed

light is _____ when an electron moves to a higher energy level

absorbed

• this energy is equal to the diff between the energies of the two orbits

light is _____ when an electron moves to a lower energy level

emitted

• this energy is equal to the diff between the energies of the two orbits

• the lost energy is negligible

electrons are at

different energy levels

• n1 is the lowest level

∆E=

E2-E1

positive energy values

absorbing energy/ moving towards the nucleus

negative energy values

releasing energy/ moving away from the nucleus

Rydberg constant equation

1/λ = (1/m² - 1/n² ) x (1.097 e^-2 nm^-1)

n

higher orbit

m

lower orbit

λ =

c/v

E=

h * v

higher amplitude =

higher intensity

h=

6.626 e^-34 J * s

1 Hz=

1 s^-1

speed of light [c]

3 e^8 m/s

closer to nucleus=

higher energy