Organic chemistry - Petroleum and Alkanes & Alkenes

Question 1

What functional group is -COOH?

Answer 1

carboxyl

Question 2

Which homologous series does the C=C functional group belong to?

Answer 2

alkene

Question 3

What is the name of the functional group present in alcohols?

Answer 3

hydroxyl

Question 4

Do alkanes have a functional group?

Answer 4

No

Question 5

What functional group is present in the organic compound formed when an alcohol reacts with a carboxylic acid?

Answer 5

COO or ester

Question 6

What are hydrocarbons?

Answer 6

organic compounds that contain hydrogen and carbon ONLY

Question 7

State one common characteristic among members of a homologous series?

Answer 7

same functional group OR
similar chemical properties OR
gradual change in physical properties from one member to the next OR
differ from one member to the next by a -CH2 unit OR
share the same general formula

Question 8

How many carbon atoms does an organic compound have if its name begins with the prefix ‘prop-‘?

Answer 8

three

Question 9

What homologous series has its members’ name end with ‘oic acid’?

Answer 9

carboxylic acid

Question 10

What method/technique is used to separate the fractions of petroleum?

Answer 10

fractional distillation

Question 11

Which fraction of petroleum is used for paving road surfaces?

Answer 11

bitumen

Question 12

Which petroleum fraction has a lower boiling point - kerosene or naphtha?

Answer 12

naphtha

Question 13

Which petroleum fraction is used as chemical feedstock?

Answer 13

naphtha

Question 14

What is the chemical formula for ethane?

Answer 14

C2H6

Question 15

Why are alkanes known as ‘saturated hydrocarbons’?

Answer 15

they contain only single C-C covalent bonds

Question 16

What are isomers?

Answer 16

compounds with the same molecular formula (reject chemical formula) but different structural formula

Question 17

Why do the the mp/bp of alkanes increase down the homologous series (i.e. as molecular size of alkane increase)?

Answer 17

stronger intermolecular forces of attraction between alkane molecules

Question 18

How does the viscosity of alkanes change?

Answer 18

Becomes more viscous as the alkane molecular size increase.

Question 19

What are the products of complete combustion of alkanes?

Answer 19

carbon dioxide and water/water vapour

Question 20

Why are alkanes generally unreactive?

Answer 20

strong C-C and C-H bonds which are difficult to break (need relatively large input of energy to break bonds)

Question 21

Name all the products in the final mixture when methane reacts with chlorine under UV light?

Answer 21

chloromethane,
dichloromethane, 
trichloromethane, 
tetrachloromethane and 
hydrogen chloride (reject hydrochloric acid)

Question 22

What is the general formula for alkenes?

Answer 22

CnH2n

Question 23

Why are alkenes known as ‘unsaturated hydrocarbons’?

Answer 23

contain one or more C=C [or carbon-carbon double bond] (reject ‘carbon double bond’)

Question 24

State the catalysts used in catalytic cracking.

Answer 24

aluminium oxide or silicon(IV) oxide (or silicon dioxide)

Question 25

What are the possible products of catalytic cracking?

Answer 25

smaller alkenes and smaller alkanes and hydrogen gas

Question 26

What are the conditions for hydrogenation of alkenes?

Answer 26

200 degree Celsius and Ni catalyst

Question 27

What is the product formed when pentene undergoes hydrogenation?

Answer 27

pentane

Question 28

What is a major application of hydrogenation?

Answer 28

to make margarine from vegetable oil

Question 29

What observation is seen when an alkene undergoes bromination?

Answer 29

reddish-brown bromine turns colourless (is decolourised)

Question 30

What is the product formed when alkenes undergo hydration?

Answer 30

alcohol