C10 Organic reactions

Question 1

what is the functional group of alkenes?

Answer 1

the double covalent bond between two carbon atoms

Question 2

what is the general formula for alkenes?

Answer 2

CnH2n

Question 3

why is there no methene?

Answer 3

there has to be two carbon atoms for the carbon-carbon double bond

Question 4

what does ‘functional group’ mean?

Answer 4

the part of the molecule which determines how it reacts

Question 5

what is a homologous series?

Answer 5

a group of molecules which all have the same functional group and react in a similar way

Question 6

what is produced during the combustion of alkenes?

Answer 6

carbon dioxide, water and unburnt carbon particles due to incomplete combustion

Question 7

what does it look like when alkenes burn in air?

Answer 7

they burn with a smoky flame

Question 8

what is hydrogenation?

Answer 8

when an alkene reacts with hydrogen

Question 9

what are the conditions for the hydrogenation of alkenes?

Answer 9

150 degrees C, nickel catalyst

Question 10

what happens during the hydrogenation of alkenes?

Answer 10

the hydrogen atoms add across the double bond to form an alkane

Question 11

what is the reaction of water and an alkene called?

Answer 11

hydration

Question 12

what happens during hydration of alkenes?

Answer 12

an alcohol is produced

Question 13

what are the conditions for the hydration of alkenes?

Answer 13

water must be steam
temperature must be around 300 degrees C
pressure must be 70 atmospheres
phosphoric acid is used as a catalyst

Question 14

what is a key fact about the hydration of alkenes?

Answer 14

the reaction is reversible

Question 15

how is the yield of an alcohol increased during the hydration of alkenes?

Answer 15

unreacted alkene and steam are passed back through the catalyst

Question 16

what happens when alkenes react with halogens?

Answer 16

the two halogen atoms add across the double bond and the double c-c bond forms a single c-c bond

Question 17

how is an alcohol formed?

Answer 17

remove an -H from an alkane
add an -OH to the alkane

Question 18

what is the functional group of alcohols?

Answer 18

-OH

Question 19

what are the first 4 alcohols?

Answer 19

methanol
ethanol
propanol
butanol

Question 20

what is the functional group of carboxylic acids?

Answer 20

-COOH

Question 21

how do you form an ester?

Answer 21

replace the H in the -COOH of a carboxylic acid and add a hydrocarbon (alkyl) group

Question 22

what is the functional group of esters?

Answer 22

-COO-

Question 23

what is fermentation?

Answer 23

the reaction in which the enzymes in yeast turn glucose into ethanol and carbon dioxide

Question 24

what does the use of ethanol as a fuel show?

Answer 24

alcohols are flammable

Question 25

how do alcohols burn?

Answer 25

with a ‘clean’ blue flame

Question 26

what is produced in the combustion of alcohols?

Answer 26

carbon dioxide
water

Question 27

how do alcohols react with sodium?

Answer 27

similar to water but less vigorous
effervescence (bubbling)
hydrogen gas is produced

Question 28

how can alcohols be oxidised (not with combustion)?

Answer 28

using chemical oxidising agents

Question 29

how can ethanol be oxidised to ethanoic acid?

Answer 29

chemical oxidising agents
microbes in the air

Question 30

what are the reactions of carboxylic acids like?

Answer 30

typical of acids
(MASH, BASHCO2, CASHCO2 ect.)

Question 31

why are carboxylic acids weak acids?

Answer 31

their molecules do not completely ionise when dissolved in water, most of the molecules stay as they are

Question 32

what is the general formula for making esters?

Answer 32

carboxylic acid + alcohol –acid catalyst–> ester + water

Question 33

what are the properties of esters?

Answer 33

distinctive smells (many are sweet and fruity)
volatile

Question 34

what are esters used for?

Answer 34

perfumes and food flavourings