Group 2 Compounds Flashcards
roup 2 elements react with water to form…?
A metal Hydroxide + Hydrogen
X + 2H2O = X(OH)2 + H2
What does the solubility of an ion depend on in group 2?
the anion (negative Ion) OH- (hydroxide) ions (singly Charged) increase solubility down group SO4 2- (sulphate) ions (Double Charged) decrease solubility down group.
how soluble in Mg(OH)2 / Magnesium hydroxide
Sparingly Soluble
Are most group 2 sulphates soluble in water?
Yes except Barium Sulphate
what is the test for group 2 sulphate ons?
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.
How is Barium Sulphate used in Medicine?
Barium Meal
barium sulphate shows up on x rays so can be used to view the inside of the body.
Barium Sulphate is poisonous, How come it is safe to be used in the barium meal?
it is insoluble so can get into your blood to poison you.
What metal is used in the extraction of Titanium?
Mg
what happens in titanuim extraction from its ore Titanium (IV) oxide
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)
How can sulphur dioxide be removed from flue gases?
reacting it with an alkali
Process called wet scrubbing
what compound may be used to remove SO2 from flue gases?
Calcium Oxide (CaO) Calcium Carbonate (CaCO3)
see book for more…
What are group 2 elements also known as?
Alkaline Earth Metals
What an Calcium Hydroxide (Ca(OH)2) be used for in agricuture?
to Neutralise acidic soils
what can Magnesium Hydroxide (Mg(OH)2)be used in in medicine?
Indigestion tablets as an antacid, it neutralises stomach acid.
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?
the one with First IE of 550kJ mol-1
it can be oxidised more easily.
Acidified barium chloride is added to solution, no precipitate is formed, what does this show?
there are no sulphate ions present
Describe the trend in reactivity with water as you go down Group 2?
Reactivity increases
How does the solubility of hydroxides change as you go down Group 2?
solubility increases as you go down
How does the solubility of sulphates change as you go down Group 2?
solubility decrases
why is barium chloride acidified before it is used to test for sulphate ions?
to get rid of any sulfites or carbonates that might affect the test result
What is a Barium meal?
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.
what happens the oxidation state of group 2 elements when they react?
The are oxidised from 0 to 2+
the charge goes X to X2+ +2e-
