Group 2 And 7

Question 1

What happens to melting point down group 2

Answer 1

Melting point generally decreases except with mg
Because metallic bonding gets weaker (size if metal ion increases)

Question 2

What do group 2 metals form when reacting with water

Answer 2

Metal hydroxide and hydrogen gas

Question 3

What is the reaction of magnesium with water vs steam

Answer 3

Reacts very slowly with cold water to form magnesium hydroxide

Readily reacts with steam to form magnesium oxide

Question 4

How do the rest do group 2 metals react with water as you go down?

Answer 4

All react with cold water to from hydroxides

Vigorous reaction increases down the group

Question 5

Why does reactivity of group 2 metals increase down the group

Answer 5

It is successively easier to remove electrons to form the 2+ ion
(Atomic radius increases)

Question 6

What is the trend in solubility do group 2 metal hydroxides down the group

What does this results in

Answer 6

Increases

So higher ph cos more hydroxide ions

Question 7

How do you test for mg ions and ca ions

Answer 7

They are sparingly soluble so react magnesium chloride or calcium chloride with sodium hydorxide to form a white precipitate

Question 8

What type of reaction is it when group 2 metal hydroxides react with acids

Answer 8

Neutralisation

Question 9

What is a use of magnesium hydroxide

Answer 9

Relieve acid indigestion
Laxative

Question 10

What is a use of calcium hydroxide
What’s another name for it

Answer 10

Raise the ph of soils in agriculture

Slaked lime

Question 11

How do you test for ammonia gas
What is reaction between ammonium ions and oh minus ions

Answer 11

Form ammonia gas and water

Damp red litmus paper turns blue

Question 12

What is the trend in solubility of group 2 metal sulfates

Answer 12

Solubility decreases down the group

Question 13

What is the chemical test for SO4 2- ions

Answer 13

Colourless solution of sodium sulfate, add barium chloride to form barium sulfate (white precipitate)

Question 14

Why does barium chloride need to be acidified first

Answer 14

To remove any other ions that could cause a false positive

Question 15

How is Barium Sulfate used in medicine

Answer 15

Barium meal

To examine a patients digestive system, the mixture containing barium sulfate coats the inner lining of intestines

Question 16

Why is is safe to have a barium meal i if barium ions are so toxic

Answer 16

Barium sulfate has a very low solubility so hardly any barium ions present in the solution and can’t dissolve into blood etc

Question 17

How is titanium extracted

Answer 17

Reacting titanium chloride with magnesium

Question 18

What are the 2 most useful properties of titanium

Answer 18

Corrosion resistant

High strength to weight ratio

Question 19

What are uses of calcium carbonate and calcium oxide

Answer 19

Neutralise sulfur dioxide present in flue gas

Flue gas desulfurisation

Question 20

What is the trend in electro negativity of group 7 elements down the group

Answer 20

Electronegativity decreases

Question 21

What is the trend in boiling points down group 7

Answer 21

Boiling point increases
More electrons so stronger van der waals forces

Question 22

What happens when halogens act as oxidising agents

Answer 22

They gain electrons to become halide ions

Question 23

What is the trend in oxidising abilities as you go down group 7
And why

Answer 23

The halogens decrease in oxidising ability

The ability to gain electrons reduces down the group

Question 24

What type do reactions are halogen displacement reactions

Answer 24

They are redox reactions

Question 25

What is the role of the halogen in halogen halide displacement reactions

Answer 25

Oxidising agent

Question 26

What are 2 disproportionation reactions that chlorine can do

Answer 26

React with water React with cold sodium hydroxide

Question 27

Define disproportionation reaction

Answer 27

A reaction in which the same element is simultaneously oxidised and reduces

Question 28

How is chlorine used in water supplies

Answer 28

Used to purify water supplies as it is toxic to bacteria Added to swimming pools too

Question 29

What are 2 risk of using chlorine in water supplies What is the compromise of this

Answer 29

Chlorine is toxic to humans so risk associated with chlorination leaks Risk of forming chlorinated hydrocarbons Sufficient chlorine added to kill bacteria but not enough to harm humans

Question 30

What is another reaction of chlorine

Answer 30

Chlorine reacts with in direct sunlight to produce hydrogen chlorine and oxygen

Question 31

What is formed when chlorine reacts with cold aqueous sodium hydroxide

Answer 31

Sodium chlorate (NaOCl) Household bleach Sodium chloride and water are 2 other products

Question 32

What is the trend in reducing ability of halide ions down the group And why

Answer 32

Reducing ability increases Ability of halide ion to lose electron increases

Question 33

What are the stages of a halide ion reacting with concentrated sulfuric acid

Answer 33

Stage 1 is displacement The halide ions reacts with sulfuric acid (which act as a proton donor) Stage 2 is redox With bromides and iodides a redox reaction occurs between concentrated sulfuric acid and halide ion Chloride and fluoride aren’t good enough reducing agents to react

Question 34

What do bromide ions reduce sulfuric acid to

Answer 34

Sulfur dioxide

Question 35

What do iodide ions reduce sulfuric acid to

Answer 35

They reduce sulfuric acid to sulfur dioxide, sulfur and hydrogen sulfur

Question 36

What is the test for identifying halide ions What is the exception of this

Answer 36

React them with acidified silver nitrate solution to produce a silver halide precipitate Silver fluoride (it is soluble so won’t form a precipitate)

Question 37

Why do you add nitric acid before adding silver nitrate solution

Answer 37

To get rid of any soluble impurities like carbonate and hydroxide ions. They’d give a false positive

Question 38

What is the colour of fluorine

Answer 38

Pale yellow gas

Question 39

What is the colour of chlorine

Answer 39

Green gas

Question 40

What is the colour of bromine

Answer 40

Red / brown liquid

Question 41

What is the colour of iodine

Answer 41

Grey solid

Question 42

Define oxidising ability

Answer 42

The power to take electrons

Question 43

What is an oxidising agent

Answer 43

Electron acceptor

Question 44

What colour solution forms when chlorine dispatches bromine ions and iodide ions

Answer 44

Bromine- orange / yellow solution Iodide - brown solution

Question 45

What is the colour of precipitates when AgCl, AgBr and AgI are formed

Answer 45

Cl - white Br - cream I - yellow

Question 46

How do you test if the precipitate is cream or white

Answer 46

Add dilute ammonia solution to the AgCl, AgBr and AgI With cl it dissolves With br it won’t With with Ai it won’t It = precipitate

Question 47

How do you further test the precipitates

Answer 47

Add concentrated ammonia solution AgBr - should dissolve AgI - won’t dissolve

Question 48

What is reducing power

Answer 48

Ability to donate electrons

Question 49

What happens when sodium halides react with concentrated sulfuric acid

Answer 49

Misty white fumes produced (NaHSO4)

Question 50

What colour is solid sulfur

Answer 50

Yellow

Question 51

How do you detect hydrogen sulfide (H2S)

Answer 51

Bad egg smell