Group 2 Flashcards
Why does the melting point decrease as you go down the group?
The distance between the positive ions and delocalised electrons increase this electrostatic forces weakens
What is the equation for Magnesium when burning in oxygen?
2Mg + O2 ——> 2MgO
What kind of flame does Magnesium burn?
bright white flame
Why does an uncleaned Mg ribbon would give false results when testing for reaction rate with Mg and acid?
Mg and MgO would react at different rates
Reaction with Mg and HCl
Mg + 2HCl —> MgCl2 + H2
Equation for Mg with steam
Mg(s) + H2O (g) —-> MgO(s) + H2(g)
Equation for Mg with warm water
Mg(s) + 2H2O (g) —-> Mg(OH)2 (s) + H2(g)
Why Titanium useful?
abundant, low density, corrosive resitant
How is titanium extracted?
using a more reactive metal (e.g. magnesium)
What is the first step in extracting titanium?
TiO2 (s) is converted to TiCl4 at 900 degrees
What is the second step in extracting titanium?
TiCl4 is purified by fractional distillation in an argon atmosphere
What is the third step in extracting titanium?
Ti extracted by Mg at 500 degrees
What is the first step equation for the extraction?
TiO2 + 2Cl2 +2C —–> TiCl4 + 2CO
What is the second step equation for the extraction?
TiCl4 +2Mg —-> Ti + 2MgCl2
What happens to the solubility of hydroxide as you go down group 2?
increases (more soluble)
What is the ionic equation for Mg(OH)2
Mg2+ (aq) + 2OH- (aq) —–> Mg(OH)2 (s)
What Magnesium hydroxide used in? and what equation
To neutralise stomach acid
Mg(OH)2 + 2HCl —> MgCl2 + 2H2O
Why is Mg(OH)2 safe to use
Mg(OH)2 is weak alkaline
What is calcium hydroxide appear as and what is it used for?
white precipitate
used in agriculture to neutralise acidic soils
Why is calcium hydroxide in water more alkaline than magnesium hydroxide?
It is more soluble so more hydroxide ions present in solution
What is the equation for use of calcium hydroxide as lime water?
Ca(OH)2 (aq) + CO2 (g) —> CaCO3 (s) + H2O (l)
What happens to solubility of sulfate in group 2 as you go down?
solubility decreases
Barium sulfate is for? and what happens after ingested?
Barium meal; The barium absorbs the x rays and the gut shows shows up on the image. Barium sulfate is low solubility so not absorbed in blood.
Equation with Barium and sulfuric acid
Ba + H2SO4 ——> BaSO4 + H2
What reagent is used when testing for sulfate ions?
BaCl2 solution acidified with HCl
What happens when BaCl2 is added to solution with sulfate ions
white precipitate formed
Ionic equation of Ba and sulfate ions
Ba2+ (aq) + SO4 2- (aq) —-> BaSO4(s)
Why is HCl used?
To react with carbonate impurities found in salts
Equation for HCl and carbonate?
2HCl + Na2CO3 —–> 2NaCl + H2O + CO2
