Group 2 Compounds

Question 1

roup 2 elements react with water to form…?

Answer 1

A metal Hydroxide + Hydrogen

X + 2H2O = X(OH)2 + H2

Question 2

What does the solubility of an ion depend on in group 2?

Answer 2

the anion (negative Ion)
OH- (hydroxide) ions (singly Charged) increase solubility down group
SO4 2- (sulphate) ions (Double Charged) decrease solubility down group.

Question 3

how soluble in Mg(OH)2 / Magnesium hydroxide

Answer 3

Sparingly Soluble

Question 4

Are most group 2 sulphates soluble in water?

Answer 4

Yes except Barium Sulphate

Question 5

what is the test for group 2 sulphate ons?

Answer 5

Makes use of the fact barium sulphate is insoluble. Add dilute HCl and then BaCl2 to a solution containing sulphate ions and then a white precipitate (barium sulphate) is formed.

Question 6

How is Barium Sulphate used in Medicine?

Answer 6

Barium Meal

barium sulphate shows up on x rays so can be used to view the inside of the body.

Question 7

Barium Sulphate is poisonous, How come it is safe to be used in the barium meal?

Answer 7

it is insoluble so can get into your blood to poison you.

Question 8

What metal is used in the extraction of Titanium?

Answer 8

Mg

Question 9

what happens in titanuim extraction from its ore Titanium (IV) oxide

Answer 9

Converted to Titanium (IV) Chloride by heating it with carbon in a stream of chloride gas. The Titanium Chloride is than purified by fractional distilation and reduced by Mg in a furnace at 1000C

TiCl4 + 2Mg = Ti + 2MgCl2
(g) (l) (s) (l)

Question 10

How can sulphur dioxide be removed from flue gases?

Answer 10

reacting it with an alkali

Process called wet scrubbing

Question 11

what compound may be used to remove SO2 from flue gases?

Answer 11

Calcium Oxide (CaO)
Calcium Carbonate (CaCO3) 

see book for more…

Question 12

What are group 2 elements also known as?

Answer 12

Alkaline Earth Metals

Question 13

What an Calcium Hydroxide (Ca(OH)2) be used for in agricuture?

Answer 13

to Neutralise acidic soils

Question 14

what can Magnesium Hydroxide (Mg(OH)2)be used in in medicine?

Answer 14

Indigestion tablets as an antacid, it neutralises stomach acid.

Question 15

One group 2 element has a first ionisation energy of 550kJ mol-1 and another 738kJ mol-1. Which would react most rapidly with water?

Answer 15

the one with First IE of 550kJ mol-1

it can be oxidised more easily.

Question 16

Acidified barium chloride is added to solution, no precipitate is formed, what does this show?

Answer 16

there are no sulphate ions present

Question 17

Describe the trend in reactivity with water as you go down Group 2?

Answer 17

Reactivity increases

Question 18

How does the solubility of hydroxides change as you go down Group 2?

Answer 18

solubility increases as you go down

Question 19

How does the solubility of sulphates change as you go down Group 2?

Answer 19

solubility decrases

Question 20

why is barium chloride acidified before it is used to test for sulphate ions?

Answer 20

to get rid of any sulfites or carbonates that might affect the test result

Question 21

What is a Barium meal?

Answer 21

it is a suspension of Barium Sulphate that a patient takes before an X ray as it si opaque to x rays so will show up the structure of the oesophagus, stomach or intestines.

Question 22

what happens the oxidation state of group 2 elements when they react?

Answer 22

The are oxidised from 0 to 2+

the charge goes X to X2+ +2e-