3.2.2 Group 2 Knowledge Flashcards
Does reactivity increase or decrease down group 2?
increases
group 2 metal + water => ?
metal hydroxide + hydrogen
Mg(s) + 2H₂O(l) ⇒ ?
Mg(OH)₂(aq) + H₂(g)
Mg(s) + H₂O(g) ⇒
MgO + H₂(g)
why does Mg react different with liquid water or steam?
steam has more energy that ignites Mg
what are the observations when Mg reacts with steam?
white solid produced, bright white light
what is the equation for the use of Mg for the extraction of Titanium from Titanium Tetrachloride
TiCl₄ + 2Mg ⇒ 2MgCl₂ + Ti
what is the role of Mg in this reaction: TiCl₄ + 2Mg ⇒ 2MgCl₂ + Ti?
reducing agent
does the solubility of group 2 hydroxides increase or decrease down the group?
increases
how soluble is Mg(OH)₂?
sparingly soluble
how soluble is Ca(OH)₂?
sparingly soluble
how soluble is Sr(OH)₂?
more soluble
how soluble is Ba(OH)₂?
completely dissolves
how do you test for Mg²⁺ and OH⁻ ions?
if Mg²⁺ ions are added to a solution containing OH⁻ ions (and vice versa) a white precipitate (Mg(OH)₂) forms
what is the precipitate formed when Mg²⁺ ions are added to a solution containing OH⁻ ions?
Mg(OH)₂, a white solid almost insoluble in water
what is the ionic equation for the reaction between Mg²⁺ ions and OH⁻ ions?
Mg²⁺(aq) + 2OH⁻(aq) ⇒ Mg(OH)₂(s)
how do you test for Mg²⁺ ions?
add Na(OH)(aq) or any other OH⁻ containing compound
how do you test for OH⁻ ions?
add Mg(NO₃)₂(aq) or any other Mg²⁺ containing compound
what is a use of Mg(OH)₂?
indigestion relief (often called ‘milk of magnesia’)
does the solubility of the group 2 sulphates increase or decrease down the group?
decreases
describe the solubility of MgSO₄
completely dissolves
describe the solubility of CaSO₄
fairly soluble
describe the solubility of SrSO₄
sparingly soluble
describe the solubility of BaSO₄
insoluble
how do you test for Ba²⁺ and SO₄²⁻ ions?
if Ba²⁺ ions are added to a solution containing SO₄²⁻ ions (and vice versa) a white precipitate (BaSO₄) forms
what is the precipitate that forms when Ba²⁺ ions are added to a solution containing SO₄²⁻ ions?
BaSO₄, a white solid that is insoluble in water
give the ionic equation for the reaction between Ba²⁺ and SO₄²⁻ ions
Ba²⁺(aq) + SO₄²⁻(aq) ⇒ BaSO₄(s)
how do you test for Ba²⁺ ions?
add H₂SO₄(aq)
how do you test for SO₄²⁻ ions?
add BaCl₂
what is a use of barium sulphate?
‘Barium meal’ - it is radiopaque allowing stomach and intestines to show up on x-rays
