Organic Chemistry 1

Question 1

How can we separate petroleum into useful fractions?

Answer 1

fractional distillation

Question 2

How do the boiling points of fractions change as you go down the fractionating column?

Answer 2

as you go down, the boiling points increase

Question 3

How does the viscosity of fractions change as you go down the fractionating column?

Answer 3

as you go down, the viscosity increases

Question 4

How do the volatilities of fractions change as you go down the fractionating column?

Answer 4

as you go down, the volatility decreases

Question 5

How do the chain lengths of fractions change as you go down the fractionating column?

Answer 5

as you go down, chain length increases

Question 6

Name the three fossil fuels.

Answer 6

coal, natural gas and petroleum

Question 7

What is the main constituent of natural gas?

Answer 7

methane

Question 8

Define the term ‘hydrocarbon’.

Answer 8

Compounds containing hydrogen and carbon only

Question 9

What process is used to separate petroleum into its fractions?

Answer 9

Fractional distillation

Question 10

What is petroleum?

Answer 10

a mixture of hydrocarbons

Question 11

What is a fraction?

Answer 11

a group of hydrocarbons with similar chain lengths

Question 12

What are features of fractions obtained from petroleum at the top of the fractionating column?

Answer 12

• lower boiling points
• runny
• volatile
• smaller chain length

Question 13

What are features of fractions obtained from petroleum at the bottom of the fractionating column?

Answer 13

• higher boiling points
• viscous
• low volatility
• bigger chain length

Question 14

What is the order of the fractions, from the smallest chain to the largest?

Answer 14

refinery gas
gasoline
naphtha
paraffin
diesel oil
fuel oil
lubricating fraction
bitumen

Question 15

What is the use of refinery gas?

Answer 15

heating and cooking

Question 16

What is the use of gasoline?

Answer 16

fuel in cars

Question 17

What is the use of naphtha?

Answer 17

chemical feedstock

Question 18

What is the use of paraffin?

Answer 18

jet fuel

Question 19

What is the use of diesel oil?

Answer 19

fuel used in diesel engines

Question 20

What is the use of fuel oil?

Answer 20

fuel in ships and home heating systems

Question 21

What is the use of lubricating oil?

Answer 21

for lubricants, waxes and polishes

Question 22

What is the use of bitumen?

Answer 22

making roads

Question 23

What is the general formula of alkanes?

Answer 23

CnH2n+2

Question 24

What is the general formula of alkenes?

Answer 24

CnH2n

Question 25

What is a functional group?

Answer 25

an atom or a group of atoms that determine the chemical properties of a homologous series

Question 26

What is a structural formula?

Answer 26

an unambiguous description of the way atoms in a molecule are arranged

Question 27

What are structural isomers?

Answer 27

compounds with the same molecular formula, but different structural formulae

Question 28

What is a homologous series?

Answer 28

a family of similar compounds with similar chemical properties due to the presence of the same functional group

Question 29

What is a saturated compound?

Answer 29

contains molecules containing only C-C single bonds

Question 30

What is an unsaturated compound?

Answer 30

contains molecules containing at least one C-C double + bond

Question 31

What are the general characteristics of a homologous series?

Answer 31

- have the same functional group - have the same general formula - trend in physical properties - similar chemical properties

Question 32

How is the bonding in alkanes?

Answer 32

single covalent saturated hydrocarbons

Question 33

Are alkanes reactive or unreactive?

Answer 33

generally unreactive, except in combustion and with halogens in UV light

Question 34

What happens in a substitution reaction?

Answer 34

one atom/group of atoms is replaced by another atom/group of atoms

Question 35

What type of reaction is the reaction between alkanes and chlorine?

Answer 35

substitution + photochemical

Question 36

What is the condition necessary for alkanes to react with chlorine? Why?

Answer 36

UV light, it gives the activation energy

Question 37

How is the bonding in alkenes?

Answer 37

contains a covalent carbon-carbon double bond unsaturated hydrocarbons

Question 38

Why is cracking used?

Answer 38

-because long chain alkanes can be turned into more useful short chain alkanes (can be used for fuels) -alkenes produced can be used to make polymers (plastic)

Question 39

What happens when an alkene comes into contact with aqueous bromine? How does this differ from an alkane's reaction with aqueous bromine?

Answer 39

alkene - decolorises aqueous bromine alkane - no difference

Question 40

How many products are formed in an addition reaction?

Answer 40

ONLY one

Question 41

What type of reaction do alkenes undergo?

Answer 41

addition

Question 42

What happens in a reaction between an alkene and hydrogen?

Answer 42

the product becomes an alkane, with the same number of carbon atoms than before but different number of hydrogen atoms

Question 43

What is necessary for an alkene to react with hydrogen?

Answer 43

nickel + 200ºC

Question 44

What happens when an alkene reacts with steam?

Answer 44

it forms an alcohol

Question 45

What is necessary for an alkene to react with steam?

Answer 45

300ºC + phosphoric acid

Question 46

What conditions are necessary for cracking?

Answer 46

high temperature catalyst - either ceramic or aluminium oxide

Question 47

What is produced in cracking?

Answer 47

shorter chain alkanes and alkenes (more useful)

Question 48

What type of reactions do alkanes undergo?

Answer 48

substitution reactions

Question 49

State in order the prefixes of alkanes and alkenes according to the number of carbon atoms.

Answer 49

1. meth- 2. eth- 3. prop- 4. but- 5. pent- 6. hex- 7. hept- 8. oct-

Question 50

Which hydrocarbons are more volatile? At the top or bottom of the fractionating column?

Answer 50

more volatile if higher up the fractionating column the smaller the molecule, the more volatile

Question 51

Which hydrocarbons are more viscous? At the top or bottom of the fractionating column?

Answer 51

the larger the molecule, the more viscous

Question 52

word equation for combustion

Answer 52

fuel (hydrocarbon) + oxygen -> carbon dioxide + water

Question 53

word equation for combustion

Answer 53

fuel (hydrocarbon) + oxygen -> carbon dioxide + water

Question 54

what is combustion

Answer 54

burning

Question 55

when does incomplete combustion occur?

Answer 55

when there is a shortage of oxygen

Question 56

what is formed as result of incomplete combustion? Why is it dangerous?

Answer 56

carbon monoxide (colorless odorless gas) and/ or soot. carbon monoxide is dangerous as it binds irreversebly to haemoglobin, reducing its ability to carry oxygen

Question 57

what are the possibilities of products in cracking

Answer 57

- alkene + hydrogen - alkene + alkane - alkane + alkene + alkane

Question 58

word equation for incomplete combustion

Answer 58

fuel + oxygen -> carbon monoxide + water

Question 59

process of fractional distillation (so para annuca - mari ignora esse card)

Answer 59

- The boiling crude oil is transferred into a large fractioning column- The lighter gaseous hydrocarbon rises the column- When gaseous hydrocarbon rises the column, it starts to cool, and when the temperature reaches below boiling points, it is converted to a liquid state.