reactions of alkenes

Question 1

are alkenes more reactive than alkanes and why

Answer 1

yes because they have double bonds

Question 2

in ALKANES what are the single bonds between two carbon atoms called

Answer 2

sigma bonds

Question 3

a double bond is…

Answer 3

stronger than a single bond

Question 4

in an alkene the double bond is made up of..

Answer 4

a sigma bond and a pi bond.

Question 5

when an alkene reacts which bond remains intact and which breaks

Answer 5

the sigma bond remains intact whilst the pi bond breaks.

Question 6

what reactions to alkenes take part in

Answer 6

addition reactions

Question 7

what’s an addition reaction

Answer 7

a small molecule is added across the double bond , causing the pi bond to break

Question 8

an unsaturated alkene forms a…

Answer 8

saturated molecule

Question 9

what’s the addition of hydrogen

Answer 9

a mixture of hydrogen gas and gaseous alkene is passed over a catalyst of nickel at a temp of 150 degrees Celsius.

Question 10

what happens in the addition of hydrogen

Answer 10

hydrogen adds across the double bond and an alkane is formed.

Question 11

what’s the reaction name for the addition of hydrogen

Answer 11

hydrogenation

Question 12

what’s the addition of halogens

Answer 12

alkenes react rapidly with halogen such as chlorine and bromine at room temperature

Question 13

what happens in the addition of halogens

Answer 13

the halogen adds across the double bond to give a halogenoalkane.

Question 14

what’s the reaction name of addition of halogens

Answer 14

halogenation , more specifically bromination , chlorination if Br and Cl used.

Question 15

what happens when bromine is added to a sample containing an alekene

Answer 15

changes from orange to colourless.

Question 16

what does the colour change show(bromine added to sample w alkene and goes from orange to colourless)

Answer 16

shows bromine has been added across the double bond

additional info- the reaction was used for a test of saturation and to prove the presence of a double bond.

Question 17

what’s addition of hydrogen halides

Answer 17

a hydrogen halide such as HCl , HBr and Hl add across the double bond to form a halogenoalkane.

Question 18

what’s addition of steam

Answer 18

steam and the gaseous alkene are to a high temperature and pressure in the presence of phosphoric acid catalyst.

Question 19

when is the addition of steam to alkenes used

Answer 19

as a method to prepare alcohols.

Question 20

what’s addition to unsymmetrical alkenes.

Answer 20

unsymmetrical alkenes also take part on addition reactions , forming a mixture of organic products.

Question 21

what’s markownikovs rule

Answer 21

when an asymmetrical alkene reacts with a hydrogen halide the hydrogen adds to the carbon atom that is already bonded to the greatest number of hydrogens