Chem- Exam 2

titration

a quantititative method to determine an acidic or basic solution’s concentration using the neurtralization reaction (acid + base —> salt + water)

buffer solution

a solution that is able to resist large changes in pH when an acid or base is added

our ____ is a buffer system keeping a pH ~ ____

blood; 7.4

buffer consists of either

1. a weak acid and its conjugate base (strong)

or

1. weak base and its conjugate acid (strong)

choose the pair that will make a buffer

A.HCl and NaCl

B.H3PO4 and Na2HPO4

C.H2SO4 and Na2SO4

D.H2CO3 and NaHCO3

D.

buffer capacity

measure of the ability of the buffer to resist pH changes

Ka

acid dissociated constant (like Keq but for specific reaction of a weak acid in water)

blood pH~7.4 is maintains partly by a _____ buffer system

carbonic acid-bicarbonate

high CO₂ shifts the equilibrium to the _____; blood becomes ____

right’ acidic (H₃O⁺)

low CO₂ shifts the equilibrium to the _____; blood becomes ____

left; basic

Oxidation Reduction (redox) reaction

reaction in which electrons are transferred from one species to another; OIL RIG

Which is reduced?
 Fe(s) + Co²⁺(aq) à Fe²⁺(aq) + Co(s)

A.Fe(s)

B.Co²⁺(aq)

C.neither

B. Co²⁺(aq)

oxidizing agent

is reduced, gains electrons, causes oxidation

reducing agent

is oxidized, loses electrons, causes reduction

What is the oxidizing agent in the following reaction?
  4 Fe + 3O₂ -->2 Fe₂O₃

A.Fe

B.O₂

C.Fe₂O₃

D.Fe³⁺

E.O^2-

B. O₂

How many electrons are transferred in the following reaction?

4 Fe + 3O₂ -->2 Fe₂O₃

organic molecules contain _____

carbon, hydrogen, may also have O,S,N,P, or halogens

saturated hydrocarbon

hydrocarbon has only C—C bonds that are single (no double bonds), and max amount of hydrogen filling every C

unsaturated hydrocarbons

hydrocarbons with at least 1 C--C double bond or a C—C triple bond

alcohol

contain the hydroxyl group (OH^-) [R—OH]

ether

contais oxygen between 2 carbon groups

thiol

contains a sulfhydryl group (R—SH)

aldehydes

have a cobonyl group, must have at least 1 hydrogen bonded to the C of the carbonyl

carbonyl gorup

ketones

carbonyl group, only carbon that are bonded to carbonyl C

amines

based off of ammonia, if you replace at least 1 H with an R-group (C-group)

alkanes

saturated hydrocarbons (109.5^o bond angles)

Name the straight chain alkane C5H12

A.Butane

B.Pentane

C.Octane

D.Nonane

B. Pentane

Draw C5H12

constitutional isomers

same molecular formulas (C₄H₁₀) but different structural formulas (how carbons bond)

substituents: halogens and akyl groups

F- fluoro

Cl- chloro

Br- bromo

I- iodo

—CH₃ methyl

—CH₂CH₃ ethyl

—CH₂CH₂CH₃ propyl

—CH₂CH₂CH₂CH₃ butyl

—CH₂CH₂CH₂CH₂CH₃ pentyl

isoproyl

3 carbon substituent attached to 2nd carbon

sec-butyl

“second”, 4 carbon substituent attached to 2nd carbon

t-butyl or tert-butyl

4 carbon substituent that froms a T or chicken foot shape

hydrocarbons are… (polarity, solubility in water and organic solvents)

nonpolar, insoluble in water, soluble in organic solvents

since there are only ____ forces bewteen hydrocarbons, alkanes tend to have relativley ____ MP and BP

dispersion forces, low

branched alkanes have a ____ MP and BP than the straight chain isomer

lower

Which has the highest mp?

A.Pentane

B.2-methylbutane

C.2,2-dimethylpropane

D.Cannot be determined

A. Pentane

cycloalkanes

carbon rings with 2 fewer H than straight-chain alkanes with same number of C; name using prefix of cyclo-

steroisomers

molecules with the same structural form but different arrangment in space (of substituents)

cis- stereoisomer

same side of ring

tans- steroisomers

opposite side of ring

conformations of alkines

structure that can be converted to one anotehr by rotaion around a bond (same molecules)

combustion

hydrocarbon + O₂ —> CO₂ + H₂O

release a lot of energy

balancing combustion reactions

1.Write the equation for the reactions

2.Balance elements that appear only once in the reactants and products

3.Balance the remaining elements

4.Make sure all coefficients are whole numbers

halogenation

reaction in which a H is replaced with a halogen

substitution reaction

reations where one group replaces another

elkenes

include double bonds between C (120^o bond angles)

alkyne

contains triple bonds between C (180^o bond angles)

strongest IMF force between alkene and alkyne molecules are _____ so MP and BP are ____ and tend to ____ as MM increases

dispersion forces; low; increase

Which has the highest mp?

A.Ethene

B.Propene

C.1-butene

D.1-pentene

D.1-pentene

geometric isomers of alkenes

cis- same side of double bond; trans- opposite sides of double bond

addition reactions

reaction in which 2 molecules add together

hydrogenation

addition of H₂

halogenation

addition of a halogen

hydration

addition of a H₂O; H add to 1 C of a double bond, OH added to the other double bond

hydrohalogenation

addition of a halogen and H (HX) coumpound (ex. HBr, HCl); breaks the double bonds and add 1 H to each C

markovnikov’s rule: in assymmetrical alkenes the major product is formed when ___________

the H adds to C double bond with more H’s

aromatic hydrocarbons

hydrocarbons that are more chemically stable than their formula would predict

molecules based off of benzene

benzene

its 6 C atoms share 6 extra electrons, very stable

toluene

another name for methylbenzene

phenol

benzene with OH group

aniline

benzene with NH₂

benzene is unusually ____ (stability); doesn’t undergo _____ reaction like alkenes, but can undergo _____ reactions like alkanes

unusually stable; no addition reaction; yes substitutions

heterocyclic aromatic compounds

have an atom other than C in the ring

classification of alcohols

classified based on number of C bonded to the C bonded to the —OH group

• primary (1^o)- 1 C attached to C bonded to OH

• secondary (2^o)- 2 C attached to C bonded to OH

• tertiary (3^o)- 3 C attached to C bonded to OH

Which is true for alcohols?

A.They are nonpolar

B.They are polar

B.They are polar

solubility _____ as the length of the nonpolar carbon chain increases in an alcohol

decreases

Which is the strongest IMF present between alcohol molecules?

A.Dispersion

B.Dipole-dipole

C.H-bonds

D.Ionic

C.H-bonds

Alcohols will have _____ mp/bp than alkanes.

A.lower

B.the same

C.higher

C. higher

method for making alcohols

hydration (add H₂O to a double bond), or reduction of aldehydes and ketones (add H₂ and reduce number of C-O bonds)

oxidation reactions

increase number of C-O bonds, decrease number of H;

oxidation reaction: if there isn’t a H off the C attached to OH group to lose, the reaction doesn’t proceed

What type of reaction is below?

A.Combustion

B.Reduction

C.Oxidation

D.Hydration

B. reduction

phenol

hydroxul group on benzene, very stable

phenols as weak acids

slighlty soluble in water, nonpolar ring and OH balance, can dissociate in water (donate H)

ether

R—O—R (R represents C group)

Which is the strongest IMF present between ether molecules?

A.Dispersion

B.Dipole-dipole

C.H-bonds

D.Ionic

b. dipole-dipole

Which statement is true?

A.Ethers of low MW should be soluble in water

B.Ethers of high MW should be soluble in water

C.Ethers should not be soluble in water

A.Ethers of low MW should be soluble in water

thiols

contain the sulfhydrul group (—SH)