Ozone Story - Halogen Reactions

Question 1

When will an alkane react with a halogen?

Answer 1

in the prescence of light

Question 2

What are rates of reaction measured in?

Answer 2

mol dm^-3 s^-1

Question 3

What are the 4 ways of measuring the rate of a reaction?

Answer 3

volume of gas produved

change in mass

change in pH

change of precipitate or colour

Question 4

What is the Bolzmann distribution curve?

Answer 4

Question 5

What is Ea?

Answer 5

activation enthalpy - the minimum amount of energy that reactants must have for a reaction to occur

Question 6

If the temperature increases, what happens to the curve on a Bolzmann distribution curve?

Answer 6

the peak is lower and shifts to the right

Question 7

What happens to the Ea on a Bolzmann curve if a catalyst is present?

Answer 7

it shifts to the left

Question 8

What can rate of reaction be affected by?

Answer 8

temperature

concentration / pressure of reactants

intensity of radiation

particle size (in solids)

presence of a catalyst

Question 9

What does CFC stand for?

Answer 9

chlorofluorocarbon

Question 10

What are the properties of CFC in the troposphere?

Answer 10

non-toxic

non-flammable

very stable

very strong bonds

Question 11

How can the overall result from a chain reaction be found?

Answer 11

add together the propogation steps

cancel any molecules that appear on both sides

Question 12

What is the spectrum of bond strengths?

Answer 12

non-polar

polar

ionic

Question 13

What is a pd-pd force?

Answer 13

permanent dipole - permanent dipole attraction

when the polar part of a molecule attracts the opposite polarity in another

Question 14

What determines the strength of a polar bond?

Answer 14

How electronegative the elements are - the bigger the gap in electronegativity the more polar the bond

Question 15

Why are symmetrical molecules not polar?

Answer 15

the forces cancel each other out

Question 16

What are the features of an id-id force?

Answer 16

present in all molecules

weak force

depends on number of electrons present

branches reduces the effect

Question 17

What are the features of pd forces?

Answer 17

can induce a pd-id force

forms pd-pd forces

only present in polar molecules

molecules have a higher melting/boiling point

stronger than id-id

Question 18

What type of bond is stronger than pd-pd interaction?

Answer 18

hydrogen bonding

Question 19

When will an id-id force be stronger than a pd-pd force?

Answer 19

if the molecules in the id-id force have significantly more electrons than the pd-pd molecules

Question 20

What is a nucleophile?

Answer 20

something that can donate a pair of electrons to form a covalent bond

Question 21

What type of molecule can be a nucleophile?

Answer 21

must have a non bonding pair of electrons

can be anions but not always

Question 22

How are nucleophillic molecules usually represented?

Answer 22

:nuc^-

Question 23

What are the conditions for nucleophilic subsitution?

Answer 23

RTP

Question 24

What is a disadvantage of nucleophilic substitution?

Answer 24

the atom economy won’t be 100%

Question 25

What happens during nucleophilic substitution with simple ions?

Answer 25

nucleophile is attracted to the 𝛿+ section of the molecule this causes the on the 𝛿+ section to move to the 𝛿- section simple ion bonds to the 𝛿+ section and 𝛿- section is given off as its own molecule

Question 26

What are the reaction conditions for the production of HBr?

Answer 26

mix NaBr with phosphoric or sulfuric acid heat under reflux

Question 27

How can a haloalkane be converted into an alcohol?

Answer 27

nucleophilic substitution using water

Question 28

How can an alcohol be converted into a haloalkane?

Answer 28

by adding a hydrogen halide

Question 29

What are the 2 ways that haloalkanes can be produced?

Answer 29

adding a hydrogen halide to an alcohol adding a hydrogen halide to an alkene

Question 30

How can a haloalkane be converted into an amine?

Answer 30

nucleophilic substitution using NH₃

Question 31

What happens to the bond enthalpies of halogens as you go down the group?

Answer 31

the bond enthalpies get less exothermic

Question 32

What are the reaction conditions for the nucleophilic substitution of a haloalkane using hydroxide ions?

Answer 32

use warm, aqueous sodium hydroxide heat under reflux

Question 33

What are the reaction conditions for the nucleophilic substitution of a haloalkane using ammonia?

Answer 33

warm the haloalkane with excess ethanolic ammonia (ammonia dissolved in ethanol) heat under reflux

Question 34

What are the reaction conditions for reacting haloalkanes with water?

Answer 34

add ethanol add silver nitrate to see results

Question 35

What is most important in a reaction - polarity or bond enthalpy?

Answer 35

bond enthalpy

Question 36

What is the method for heating under reflux?

Answer 36

heat reagents in a round bottomed flask with a condenser vertically attached to it, so that evaporated products will condense and drip back down into the flask