group 2 Flashcards
what is group 2 known as?
the alkali earth metals
in all of their reactions, the group 2 metals are
oxidised
what happens when group 2 metals react with water?
● metal is oxidised
● hydrogen is reduced
what are the observations when Be reacts with water?
unreactive with water and steam
what is the equation for Be reacting with water?
x
what are the observation when Mg reacts with water?
● very slow reaction with water
● faster with steam
what is the equation for Mg reacting with water and stream?
● water: Mg(s) + 2H2O(l) -> Mg(OH)2(aq) + H2(g)
● steam: Mg(s) + H2O(g) -> MgO(s) + H2(g)
what are the observations when Ca reacts with water?
● fizzing / effervescence
● when in cold water
what is the equation for Ca reacting with water?
Ca(s) + 2H2O(l) -> Ca(OH)2(s) + H2(g)
what are the observations when Sr reacts with water?
● reacts vigorously
● with cold water
what is the equation for Sr reacting with water?
Sr(s) + 2H2O(l) -> Sr(OH)2(s) + H2(g)
what are the observations when Ba reacts with water?
● reacts more vigorously
● with cold water
what are the observations when Ba reacts with water?
Ba(s) + 2H2O(l) -> Ba(OH)2(aq) + H2(g)
how are group 2 hydroxide formed?
when group 2 reacts with water
what is the solubility of Mg(OH)2?
● insoluble
● equation: Mg(OH)2(s) -> almost insoluble
● white ppt
what is the solubility of Ca(OH)2?
● slightly soluble
● equation: Ca(OH)2 (s) -> Ca2+ (aq) +2OH-(aq)
● cloudy
what is the solubility of Sr(OH)2?
● soluble
● equation: Sr(OH)2 (s) -> Sr2+ (aq) + 2OH-(aq)
● colourless
what is the solubility of Ba(OH)2?
● soluble
● equation: Ba(OH)2(s) -> Ba2+ (aq) + 2OH-(aq)
● colourless
what is the trend in solubility down group 2 hydroxides?
increases
what is the trend in colour down group 2 hydroxides?
white to colourless
how are group 2 sulfates formed?
when group 2 metal reacts with sulfate ions (e.g. sulfuric acid)
what is the solubility of MgSO4?
● soluble
● equation: x
● colourless
what is the solubility of CaSO4?
● slightly soluble
● equation: Ca2+ (aq) + SO42-(aq) -> CaSO4 (s)
● cloudy
what is the solubility of SrSO4?
● insoluble
● equation: Sr2+ (aq) + SO42- (aq) -> SrSO4(s)
● white precipitate
what is the solubility of BaSO4?
● insoluble
● equation: Ba2+ (aq) + SO42- (aq) -> BaSO4(s)
● white precipitate
what is the trend in solubility down group 2 sulfates?
decreases
what is the trend in colour down group 2 sulfates?
colourless to white
what
explain extraction of Ti
● strong, low density, high melting point
● used in aerospace industry and replacement hip joints
● abundant but difficult to extract
● metals are typically extracted by:
metal oxide + carbon -> metal + carbon dioxide
● however, method produces titanium carbide which is very brittle so different method must be used
● 1. titanium oxide is reacted with chlorine and carbon
TiO2 + 2Cl2 + 2C -> TiCl4 + 2CO
● 2. titanium chloride is reduced using magnesium
TiCl4 + 2Mg -> 2MgCl2 + Ti
explain milk of magnesia
● Mg(OH)2
● indigestion remedy
● neutralises excess stomach acid
explain calcium hydroxide
● slaked lime
● treats acidic soil
explain barium sulfate
● insoluble
● barium metal -> outlines gut in medical x-rays
● barium is toxic but due to being an insoluble compound it is safe
