Group 2 Flashcards
General equation for Ca, Sr or Ba with water
M(s) + 2H2O(l) —> M(OH)2 + H2(g)
How is the reaction of Mg and water different
UNCLEAN Mg reacts very slowly with water, favoured to react with steam
If oxide layer around Mg is cleaned, will react very slowly with liquid water
Mg reaction equation with steam + observation
Bright white flame
Mg(s) + H2O(g) —> MgO(s) + H2(g)
How is Mg used to extract titanium from its ore rutile
TiO2 + 2Cl2 + 2C —> TiCl4 + 2CO
TiCl4 + 2Mg —> Ti + 2MgCl2
Mg used as reducing agent as C would produce brittle TiC
Simple ionic equation for group 2 and hydroxide
M2+(aq) + 2OH-(aq) —> M(OH)2
state of product depends on solubility
Trend of solubility of hydroxides down group 2
Solubility increases down group
Mg(OH)2 is insoluble
Use of Mg(OH)2 in medicine
Milk of magnesia , neutralise excess stomach acid as antacid tablets
Use of Ca(OH)2 in agriculture
Used to neutralise acidic soils for growing crops
CaO and CaCO3 use in flue gas removal
CaO + SO2 —> CaSO3
CaCO3 + SO2 —> CaSO3 + CO2
Simple ionic equation
Acidified barium chloride with sukfate ions or sulfuric acid
Ba2+(aq) + SO4^2-(aq) —> BaSO4(s)
White precipitate
Trend in group 2 sulfates solubility
Decrease going down the group
MgSO4 is soluble
Why must barium chloride be acidified when testing for sulfate ions
Prevent formation of barium carbonate, atmospheric CO2 dissolve in solution
Use for barium sulphate in medicine and why it’s suitable
Barium meal. It is dense and absorbs x rays
Insoluble and so non toxic
