WWU Chem 351 Chpt 3 – Flashcards

-CH2-

Members that difere in number of methylene groups

C4H10

"n-butane" (n-denotes carbon on mother chain it's attached to)

;

"iso-butane" b/c it's a branched isomer

Find the longest continuous chain of C's and use the name of this as the base of the compound (i.e. 6-C's="hexane")

Use the chain with more substituents if there are 2 main chains of equal length

Number main chain beginning with end nearest to a substituent

-Name substituent groups as alkyl groups, give location by number on main chain

-Replace "ane" on alkane with "yl"

When there are 2+ substituents, list in alphabetical order.  When there are 2+ of the same, use prefixes. 

Use longest alkyl as base, number with head carbon on main chain for complex subs.

As MW and SA increase, BP does as well.

Same relationship, but those with EVEN numbers of carbon pack tighter and require a higher MP.  Also, BRANCHING INCREASES MP as they pack tighter.

Alkane + O2 --> CO2 + H2O + Heat

Alkane + Halogen ---> alkyl alides (CH2Cl2)

(usually requires light/heat)

PERFECT 109.5 degrees.

2 CH3's with overlapping sp3's to form a sigma bond.

Angle between H-C bonds on front and back C.

-Eclipsed=0 deg.<--MOST PE from torsion

-Staggered=60 deg.

-Skew=any theta

C3H8

Higher, approximately 1.2 kJ.

Between the two methyl groups

totally eclipsed= methyls pointed in same direction, 0 deg

gauche= 60 deg, methyls to L and R of ea other

anti= 180 deg, CH3 point opp directions

Lowest= anti, then gauche from separating CH3s

CnH2n

Number so that substituted Cs get lowest numbers, name in alphabetical order

cis= subs point to same face, trans= point to opp face

C-C bonds don't hae optimum overlap, so require angle other than 109.5 deg. and have eclipsed confs

;

(CH2)n + 3/2 O2 --> nCO2 + nH2O+ n(energy/CH2)

Find energy by dividing heat of combustion by n.

high ring strain to 60 deg bond angle, eclipsed torsional strain, planar geometry

slightly folded form w/ 88 deg bond angle

envelope conf that undulates with up/down motion of methylene grps

NO RING STRAIN

Chair is most stable with all at 109.5 deg, boat stable but has torsional strain, twisted boat reduces eclipse of flagpole H's.

Half chair has highest energy (rocket ship!)

Axial= H-C bond parallel to ring

-odd Cs have axial up

-even Cs have axial down

Equitorial= H-C bond point along ring equator

-odd Cs have equitorial down

-even Cs have equitorial up

boat conformation

equitorial, creates anti conformation

when methyls are smooshed near another H when in axial position

EQUITORIAL

Fine, present in equal amounts but higher energy b/c of 1 axial sub.

Large should be equitorial, small axial if can't have cis.  Want tert-butyls in equitorial.

"bicyclo[x.y.z]prefix'tane'"

-x= largest c-bridge

y=mid c-bridge

z=smallest # c-bridge

cis= need 1 bond to right ring axial, 1 equitorial

trans=both bonds to right ring need to be equitorial, rigid conf