Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Chemistry Module 3 > 3.1.3 Halogens > Flashcards

3.1.3 Halogens Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Chemistry flashcards Periodic Table flashcards Chemistry 101 flashcards Organic Chemistry 101 flashcards
1
Q

what do all halogens exist as

A

diatomic molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

fluorine

A

F2
very pale yellow gas
highly reactive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

chlorine

A

Cl2
greenish
reactive gas
poisonous in high concentrations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

bromine

A

Br2
red liquid
gives off dense brown/orange poisonous flames

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

iodine

A

I2

shiny grey solid sublimes to purple gas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

trend in melting and boiling point down the group

A

increases
molecules are larger, more electrons so have more induced dipole-dipole forces
as forces get larger more energy must be put in to break them
increases MP and BP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

trend in reactivity down the group

A

decreases
atoms get bigger with more shielding, harder to attract and accept electrons
form 1- ions less easily down the group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what will chlorine displace

A

bromide and iodide ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what will bromine displace

A

iodide ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

chlorine in potassium chloride

A

very pale green solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

chlorine in potassium bromide

A

yellow solution

Cl has displaced Br

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

chlorine in potassium iodide

A

brown solution

Cl has displaced I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

bromine in potassium chloride

A

yellow solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

bromine in potassium bromide

A

yellow solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

bromine in potassium iodide

A

brown solution

Br has displaced I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

iodine in potassium chloride

A

brown solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

iodine in potassium bromide

A

brown solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

iodine in potassium iodide

A

brown solution

no reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

colour of chlorine in solution

A

very pale green

often colourless

20
Q

colour of bromine in solution

A

yellow solution

21
Q

colour of iodine in solution

A

brown solution

22
Q

colour of chlorine in organic solvent

A

colourless

23
Q

colour of bromine in organic solvent

A

yellow

24
Q

colour of iodine in organic solvent

A

purple

25
Q

displacement reactions of chlorine if organic solvent is added

A

potassium chloride: colourless, no reaction
potassium bromide: yellow, Cl has displaced Br
potassium iodide: purple, Cl has displaced I

26
Q

displacement reactions of bromine if organic solvent is added

A

potassium chloride: yellow, no reaction
potassium bromide: yellow, no reaction
potassium iodide: purple, Br has displaced I

27
Q

displacement reactions of iodine if organic solvent is added

A

solution stays purple if potassium chloride, bromide or iodide is added as there is no reaction that occurs

28
Q

explain why chorine is more reactive than bromine

A

chlorine is more reactive than bromine
it will gain an electron and form an 1- ion more easily
because chlorine is smaller, has less shielding so the electron is attracted more strongly than in bromine

29
Q

example of a displacement reaction equation using chlorine and bromine

A

Cl2 (aq) + 2Br- (aq) -> 2Cl- (aq) + Br2 (aq)

30
Q

disproportionation reaction definition

A

a reaction where an element is both oxidised and reduced

31
Q

example of a disproportionation reaction: chlorine with water

A

chlorine with water
Cl2 (g) + H2O (l) -> HClO (aq) + HCl (aq)

if universal indicator was used it would initially turn red then HClO would bleach it colourless
chlorine both oxidised and reduced: 0 in Cl2 then -1 in HCl and +1 in HClO

32
Q

use of chlorine

A

in water to treat bacteria (drinking water and swimming pools)
benefits outweigh risk of toxic effects and risks from forming chlorinated hydrocarbons

33
Q

example of a disproportionation reaction: chlorine with sodium hydroxide

A

NaOH MUST BE COLD AND DILUTE
halogen will fade to colourless

Cl2(aq) + 2NaOH (aq) -> NaCl (aq) + NaClO (aq) + H2O (l)

34
Q

uses for the products of chlorine and sodium hydroxide disproportionation

A

NaCl and NaClO (sodium chorate I) is used as bleach and to disinfect bacteria

35
Q

what happens if the NaOH is hot

A

different disproportionation reaction will occur
3Cl2 + 6NaOH -> NaClO3 +5NaCl + 3H2O
forms sodium chlorate (V)

36
Q

testing for halides

A

add nitric acid

then add silver nitrate

37
Q

why do you need nitric acid when testing for halide ions

A

to react with any carbonates present to prevent formation of precipitate Ag2CO3
would mask the desired observations

38
Q

test for halides: fluorine

A

no precipitate

39
Q

test for halides: chlorine

A

white ppt

Ag+ (aq) + Cl- (aq) -> AgCl (s)

40
Q

test for halides: bromine

A

cream ppt

Ag+ (aq) + Br- (aq) -> AgBr (s)

41
Q

test for halides: iodine

A

yellow ppt

Ag+ (aq) + I- (aq) -> AgI (s)

42
Q

what test can you do following the test for halide ions to distinguish ppt formed

A

add ammonium

of variable concentrations

43
Q

silver chloride in ammonia

A

dilute: dissolves
conc: dissolves

AgCl (s) + 2NH3 (aq) -> [Ag(NH3)2] + (aq) + Cl- (aq)
colourless solution

44
Q

silver bromide in ammonia

A

dilute: partially dissolves
conc: dissolves

AgBr (s) + 2NH3 (aq) -> [Ag(NH3)2] + (aq) + Br- (aq)
colourless solution

45
Q

silver iodide in ammonia

A

doesn’t dissolve in any concentration

it is too insoluble

Chemistry Module 3 (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions