Chem unit 2

Question 1

Compounds with carbon and hydrogen atoms are called

Answer 1

hydrocarbons

Question 2

Most important sources of hydrocarbons are

Answer 2

petroleum and natural gas

Question 3

Long molecular hydrocarbons are

Answer 3

solids, small ones are the liquids and the shortest are gases.

Question 4

ALIPHATIC: hydrocarbons

Answer 4

or open chain hydrocarbons. They are either straight chained or branched. They can be saturated (single bond) or unsaturated. (multiple bond)

Question 5

AROMATIC: hydrocarbons

Answer 5

or closed chain (cyclic) compounds

Question 6

The covalent bond between carbon atoms is (weak or strong)

Answer 6

very strong which is the reason behind long and stable chains in organic compounds. Carbon atom has 4 electrons in the valence shell which makes it neither a cation nor an anion. It shares electrons with other bonding atoms.

Question 7

carbon cattion or anion?

Answer 7

niether

Question 8

ALKANES: General formula is

Answer 8

CnH2n+2

Question 9

ALKENES: General formula

Answer 9

CnH2n

Question 10

ALKYNES: General formula is

Answer 10

CnH2n-2

Question 11

AROMATIC COMPOUNDS: General formula is

Answer 11

CnH2n-6

Question 12

benzene ring

Answer 12

C6H6

Question 13

ALKYL HALIDES

Answer 13

are compounds where halogens replace the hydrogen atoms in alkanes. If H atom of methane (CH4) is replaced by a Cl atom, methyl chloride is formed. (CH3Cl)

Question 14

alkanes undergoing combustion

Answer 14

to yield carbon dioxide, water and energy.

C3H8 + 5O2 –> 3CO2 + 4H2O

Question 15

Alkanes undergoing halogenation

Answer 15

is a substitution reaction when exposed to very high temperature.CH4 + Cl2 –> CH3Cl + HCl

Question 16

Alkanes undergoing nitration

Answer 16

Nitration is the reaction between alkane vapor and conc. HNO3 vapor.
CH4 + HNO3 –> CH3 – NO2 + H2O

Question 17

alkenes

undergoing hydration

Answer 17

hydration where H from H-OH is attached to the C atom with larger number of H atoms, whereas the OH group from water is attached to the other C atom in the double bond of an alkene.
CH3- CH = CH2 + H-OH –> CH3 – CHOH – CH3

Question 18

alkenes undergoing polymerization

Answer 18

is another reaction of alkenes where different alkenes are attached together to form a larger molecule. CH2=CH2 + CH2=CH2 + CH2=CH2 –> -CH2-CH2-CH2-CH2-CH2-CH2-

Question 19

the single unit of CH2=CH2 is called a…. and the product is called a…

Answer 19

single unit is a monomer. product is a polymer

Question 20

Alkynes also undergo polymerization reactions. When

Answer 20

ethyne is passed through a red hot glass tube, it trimerizes to give benzene.
3 CH= CH –> C6H6

Question 21

Alkynes undergo halogen addition but yields

Answer 21

2 products due to the presence of 2 pi bonds. Thus ethyne can react with 2 halogen molecules. CH=CH +Cl2 –> CHCl = CHCl

CH= CH + 2Cl2 –> CHCl2 – CHCl2

Question 22

alkynes undergoing hydrogenation

Answer 22

where addition with H atoms take place in the presence of N, Pd or Pt as catalysts.
CH=CH + H2 –> CH2=CH2 –> CH3- CH3

Question 23

carbon electron configuration in ground state and excited state

Answer 23

ground state 1s2 2s2 2p2.

excited state 1s2 2s1 2p3

Question 24

Experimental evidence has shown that the bond angles in methane are not arranged that way but are ….. giving the overall shape of a…

Answer 24

109.5

a tetrahedron

Question 25

Experimental evidence has also shown that the H-N-H bond angles in ammonia (NH3) are

Answer 25

107 degrees

Question 26

and the H-O-H bond angles in water are

Answer 26

105 degrees

Question 27

It is clear from these bond angles that the non-bonding pairs of electrons occupy a reasonable amount of space and are pushing the hydrogen atoms

Answer 27

closer together

Question 28

. In this model, atoms and pairs of electrons will be arranged to minimize the repulsion of these atoms and pairs of electrons.

Answer 28

VSEPR

Question 29

The number of these new hybrid orbitals must be equal to the

Answer 29

numbers of atoms and non-bonded electron pairs (lone pairs) surrounding the central atom

Question 30

Criteria for Aromaticity:

Answer 30

1) Pi bonds must lie within cyclic structure. 2) Each atom in the cycle must have p orbital, forming p orbital loop. 3) All p orbitals in the loop must overlap and must be planar. 4) Hückel’s Rule: orbital arrangement must result in a lowering of energy. 4n+2 pi electrons (n is an integer: 0 to 5 usually) in the loop

Question 31

Hückel’s Rule:

Answer 31

Obital arrangement must result in a lowering of energy. 4n+2 pi electrons (n is an integer: 0 to 5 usually) in the loop

Question 32

Hydrogenation is what kind of reaction

Answer 32

Addition

Question 33

Halogenation reaction is what kind

Answer 33

Substitution

Question 34

Hydration is what kind of reaction

Answer 34

H2O attaches to CH with more bonds | And H goes to the CH with more hydrogen atoms

Question 35

Nitration is what kind of reaction

Answer 35

Substitution h2O

Question 36

What reactions have only a single product

Answer 36

Halogentation | Hydrogenation

Question 37

Cis versus trans

Answer 37

Cis same | Trans different