2.2 Group 2 - Alkaline Earth Metals Flashcards
Describe the two stages of extracting titanium from its ore.
→ titanium dioxide is heated with carbon & chlorine, forming titanium chloride
→ titanium is reduced by magnesium, forming magnesium chloride & pure titanium
Explain why the usual method of extracting metals does not work for titanium
- heating titanium dioxide with carbon produces a carbide
- this is too brittle to be useful as an engineering material
Write the equation for the reaction between magnesium and steam.
Mg (s) + H₂O (g) → MgO (s) + H₂ (g)
Write an ionic equation, with state symbols, to show the reaction of calcium with an excess of water.
Ca (s) + 2H₂O (l) → Ca²⁺ (aq) + 2OH⁻ (aq) + H₂ (g)
State the role of water in the reaction with calcium.
State a use of magnesium hydroxide in medicine.
neutralises stomach acid (antacid)
From Mg(OH)₂ to Ba(OH)₂, the solubility in water…
From Mg to Ba, the first ionisation energy…
From Mg to Ba, the atomic radius…
Write the simplest ionic equation for reaction between acidified barium chloride & a solution containing sulfate ions.
Ba²⁺ + SO₄²⁻ → BaSO₄
Explain why acid should be added before barium chloride when testing for sulphate ions.
to remove any carbonate ions because:
→ they react with barium chloride to form barium carbonate
→ barium carbonate will precipitate to give a false positive test for sulphate ions
State why sulfuric acid should not be used to acidify barium chloride.
- sulfuric acid contains sulphate ion
- which reacts with barium chloride to form white precipitate
- (false positive)
Suggest why magnesium chloride wouldn’t be a suitable test for sulphate ions.
- magnesium chloride would react with sulphate ions to form magnesium sulphate
- magnesium sulphate is soluble
- will not form a precipitate to give any indication of a positive result
In the extraction of strontium from SrO, what role does aluminium have?
- gains oxygen therefore reducing agent
Explain why the precipitate of silver chloride is washed several times with deionised water.
to remove soluble impurities
to remove excess silver nitrate