(2) Alkanes And Cycloalkanes

Question 0

Ethene characteristics

Answer 0

Planar with bond angles close to 120

Three atoms bonded to each carbon sp2

Question 1

Small alkanes and boiling points

Answer 1

Have the lowest boiling point

Four bonds, tetrahedral at 109.5 degrees apart

Question 2

Acetylene

Answer 2

Linear with bond angles 180 degrees
Sp
Two pi bonds formed

Question 3

Sources of alkanes

Answer 3

Natural gas mainly methane propane and ethane
Petroleum is a liquid mixture containing 150 hydrocarbons
Boiling of crude oil gives fractions based on bp

Question 4

Alkane physical properties

Answer 4

Increase with number of carbons

Branched carbons generally have lower BP than unbranched with the same number of carbons

Question 5

Intermolecular forces in alkane

Answer 5

Alkane intermolecular forces are VDF

Alkane a are non polar but have induced dipole-induced dipole between polar molecules (one positive end one of molecule aligns with negative end of another) net F is attractive

Larger dipoles means higher BP and heats of vaporization

Question 6

Alkane hydrogen bonding

Answer 6

Strong dipole dipole attraction

Organic molecule must have NH or OH

Question 7

Alkane solubility

Answer 7

Insoluble in water

Question 8

Hydrocarbon acidity

Answer 8

Very weak acids, allkynes strongest acids (increase of s character)

Question 9

Testing the polarity

Answer 9

Any element more electronegative on C has same effect as O on oxidation state of C

Any element less electronegative than C has same effect has H on oxidation state of C

Question 10

Combustion is exothermic

Answer 10

Isomers or the more stable molecules will release the least amount of energy

Question 11

Oxidation

Answer 11

Increased number of bonds to oxygen or decreased number of bonds to hydrogen

Question 12

Reduction

Answer 12

Decreased number of bonds to oxygen or increased number of bonds to hydrogen