Group 7 - The Halogens Flashcards Preview

Y12 AS Chemistry > Group 7 - The Halogens > Flashcards

Flashcards in Group 7 - The Halogens Deck (53)
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1
Q

What colour is F2 at room temperature?

A

Pale yellow

2
Q

What is the physical state of F2 at room temperature?

A

Gas

3
Q

What colour is Cl2 at room temperature?

A

Green

4
Q

What is the physical state of chlorine at room temperature?

A

Gas

5
Q

What colour is Br2 at room temperature?

A

Red-brown

6
Q

What is the physical state of Br2 at room temperature?

A

Liquid

7
Q

What colour is I2 at room temperature?

A

Grey

8
Q

What is the physical state of I2 at room temperature?

A

Solid

9
Q

What is the trend in boiling points of halogens down a group?

A

Increases

10
Q

Why does the boiling point increase down a group?

A

Due to the increased strength of the Van der Waals as the relative mass of molecules increases

11
Q

What is the trend in electronegativity down a group of halogens?

A

Decreases

12
Q

Why does electronegativity increase down the group?

A

The halogens are highly electronegative
Larger atoms attract less than smaller ones
Their outer electrons are further from the nucleus and more shielded

13
Q

Are halogens oxidising or reducing agents? Why?

A

Oxidising agents

They gain an electron

14
Q

What happens to the oxidising power of the halogens as you move down the group?

A

They become less oxidising

15
Q

What does “halide” describe?

A

The negative X- ion

16
Q

What does the term “Halogen” refer to?

A

The atom X or the molecule X2

17
Q

What colour is potassium chloride solution? (KCl)

A

Colourless

18
Q

What is the reaction between potassium chloride solution and chlorine water?

A

No reaction

19
Q

What colour is chlorine water (Cl2)?

A

Colourless

20
Q

What colour is potassium bromide solution (KBr)?

A

Colourless

21
Q

What is the reaction between potassium bromide solution and chlorine water?

A

Orange solution (Br2) formed

22
Q

What colour is potassium iodide solution (KI)?

A

Colourless

23
Q

What is the reaction between potassium iodide solution and chlorine water?

A

Brown solution (I2) formed

24
Q

What is the colour of bromine water (Br2)?

A

Orange

25
Q

What is the reaction between potassium chloride solution and bromine water?

A

No reaction

26
Q

What is the reaction between potassium bromide solution and bromine water?

A

No reaction

27
Q

What is the reaction of potassium iodide solution and bromine water?

A

Brown solution (I2) formed

28
Q

What colour is iodide solution (I2)?

A

Brown

29
Q

What is the reaction between the potassium chloride solution and iodine solution?

A

No reaction

30
Q

What is the reaction between potassium bromide solution and iodide solution?

A

No reaction

31
Q

What is the reaction between potassium iodide solution and iodine solution?

A

No reaction

32
Q

What is the equation for the displacement reaction of chlorine and potassium iodide ions?

A

Cl2 + 2KI -> 2KCl +I2

33
Q

What is the ionic equation for the displacement reaction of chlorine and potassium iodide ions?

A

Cl2 + 2I- -> 2Cl- + I2

34
Q

What is the equation for the displacement reaction between chlorine and potassium bromide?

A

Cl2 + 2KBr -> 2KCl + Br2

35
Q

What is the ionic equation for the displacement reaction between chlorine and potassium bromide?

A

Cl2 + 2Br- -> 2Cl- + Br2

36
Q

What is the equation for the displacement reaction between bromine and potassium iodide?

A

Br2 + 2KI -> 2KBr + I2

37
Q

What is the ionic equation for the displacement reaction between bromine and potassium iodide?

A

Br2 + 2I- -> 2Br- + I2

38
Q

Why won’t iodine displace either Cl- or Br- halide?

A

It is below chlorine and bromine in group 7 so it is less reactive

39
Q

What is formed when you mix chlorine gas with cold, dilute sodium hydroxide solution at room temperature?

A
Sodium chlorate (I) solution
NaClO
40
Q

What is a use of NaClO?

A

Household bleach

41
Q

What is disproportionation?

A

In the reaction, chlorine being both oxidised and reduced

42
Q

What is the equation for the formation of bleach?

A

2NaOH +Cl2 -> NaClO + NaCl + H2O

43
Q

What is chlorine’s oxidation state in Cl2?

A

O

44
Q

What is chlorine’s oxidation state in NaClO?

A

+1

45
Q

What is chlorine’s oxidation state in NaCl?

A

-1

46
Q

What happens when chlorine reacts with water?

A

Disproportionation

47
Q

What is formed when chlorine reacts with water?

A

A mixture of chloride ions and chlorate (I) ions

48
Q

What is the equation when chlorine reacts with water?

A

Cl2 + H2O 2H+ + Cl- + ClO-

49
Q

What is chlorine’s oxidation state in Cl-?

A

-1

50
Q

What is chlorine’s oxidation state in ClO-?

A

+1

51
Q

Why is chlorine used in water treatment?

A

Chlorate ions kill bacteria

52
Q

Why is chlorine an important part of water treatment?

A

It kills disease-causing microorganisms
Prevents reinfection further down the supply
Prevents the growth of algae, eliminating bad tastes and smells and removing discolouration caused by organic compounds

53
Q

What are the risks of using chlorine in water treatment?

A

Chlorine is toxic
Harmful if chlorine gas is breathed in - irritates the respiratory system
Liquid chlorine causes chemical burns on the skin and eyes