Unit 4: Chemical Reactions

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2 electrons

2 electrons

1 line in Lewis Dot Structure (single bond)

4 electrons

2 lines in Lewis Dot Structure (double bond)

0

Oxidation # of an element by itself

+1

Oxidation # of group 1 elements

+2

Oxidation number of group 2 elements

-1

Oxidation # for halogens (group 7)

ion charge

Sum of oxidation #s for a polyatomic ion

0 (neutral)

Sum of oxidation numbers for a neutral compound

+1 with nonmetals, -1 with metals

H oxidation #

-2, -1 in peroxide (H2O2)

O oxidation number

Always -1

F oxidation number

Cl2 oxidation #

0

Na oxidation number

0

S6 oxidation number

0

P4 oxidation number

0

K+ oxidation number

+1

N3- oxidation number

-3

Mg2+ oxidation number

+2

K oxidation number (in KCL)

+1

Cl oxidation number (in KCl)

-1

Mg oxidation number (in MgO)

+2

O oxidation number (in MgO)

-2

C oxidation number (in CO)

+2

N oxidation number (in NH3)

-3

H oxidation number (in NH3)

+1 (x3 = H3)

Zn oxidation number (in ZnH2)

+2

H oxidation number (in ZnH2)

-1

Gases that behave ideally

Gas particles have negligible volume, gas particles are of equal size, temp = 0, atm = 1

acids

Donates protons

Bases

Accepts protons

HCl

Strong acid

HBr

Strong acid

HI

Strong acid

HNO3

Strong acid

H2SO4

Strong acid

HClO4

Strong Acid

NaOH

Strong base

LiOH

Strong base

KOH

Strong base

Ba(OH)2

Strong base

Physical Change

substance has a change in properties but not a change in chemical composition

intermolecular forces, bonds breaking

Physical changes involve a change in ______________, and usually don’t involve ____________

examples of physical changes

phase changes, separation of mixtures (distillation, filtration, chromatography)

Chemical Change

Substance is transformed into a new substance with different compositions

breaking or forming chemical bonds; reversible

Chemical changes involve ______________________ and are _________________

examples of chemical changes

2 H2O —> 2 H2 + O2

AgNO3 + NaCl —> NaNO3 + AgCl

strong acids/bases, ionic compounds, and aqueous substances

When writing net ionic equations, break up ______________________________

solid substances, covalent substances, weak acids/bases, gas, pure liquid/solid, insoluble (slightly soluble) ionic solids

When writing net ionic equations, don’t break up _________________________

Hg^(2+)(aq) + 2I(-)(aq) —→ HgI2(s)

charges and states of matter (solid, liquid, gas, aqueous)

When writing net ionic equations, always include ____________

Ca(NO3)2(s) —> Ca^(2+)(aq) + 2NO3^(-)(aq)

Titrant

in a titration, the _______ is the solution of known concentration (aka the standard solution)

Analyte

in a titration, the ________ is the solution of unknown concentration

equivalence point

point where just enough titrant has been added to react with the analyte; May be indicated by a color change

end point

observable event of the equivalence point

concentration1 (of H+, OH-, etc.) x V1 = concentration2 x V2

equivalence point on titration curve

pKa on titration curve

buffer region on titration curve

pKb on titration curve

Bronsted Lowry Acid

a substance that can donate a proton (H+) to another molecule.

Bronsted Lowry Base

a molecule or ion that accepts a hydrogen ion, or proton, in a reaction

conjugate acid

the bronsted lowry base after it accepts a proton

conjugate base

the bronsted lowry acid after it loses a proton

sometimes redox reactions

synthesis/combination, decomposition “heating” reactions are ____________

always redox reactions

combustion “burning” reactions, single replacement reactions

never redox reactions

double replacement, bronsted lowry acid base reactions

precipitate, gas, or weak electrolyte

in a double replacement reaction, the product is a ______________________

oxidation

electrons are lost; oxidation # increases (more +); the anode in an electrode cell; reducing agent

oxidation reaction

A —> A+ + e-

Reduction

e- gained, oxidation number decreases (more -), oxidizing agent, cathode in electrode cell

reduction reaction

A + e- —> A-

the electrons

when balancing half reactions, balance _________________ of each half reaction

elements

when writing half reactions, balance ___________ (not H or O)

H2O

When writing half reactions, balance O with ________

H+

When writing half reactions, balance H with ____

electrons

when writing half reactions, balance charges with _______