Reactions Of Ions In Aqueous Solution Flashcards
What is the equation for pH
-log10[H+]
When are metal aqua complexes formed
When we add a transition metal compound to water
Draw the structure of (Cu(H2O)6)2+
Draw the structure of (Fe(H2O)6)2+
Draw the structure of (Fe(H2O)6)3+
Draw the structure of (Al(H2O)6)3+
What is the pH of metal-aqua ions
Below 7, they are acidic in solution
What affects how acidic a metal aqua ion is in solution
The charge of the ion
What is the equation for when (Fe(H2O)6)2+ reacts with water
(Fe(H2O)6)2+(aq) + H2O(l) ⇌ (Fe(H2O)5(OH))+(aq) + H3O+(aq)
What is H3O+ ion called
Hydroxonium ion
What is the term for using water to break a portion of a complex off using water
Hydrolysis
What is the equation for when (Fe(H2O)6)3+ reacts with water
(Fe(H2O)6)3+(aq) + H2O(l) ⇌ (Fe(H2O)5(OH))2+(aq) + H3O+(aq)
Why do more positively charged ions form more acidic solutions
More positively charged ions have a greater charger density
and are more polarising
And so attract electrons in the O-H bond in water ligands more strongly, weakening the bond
Therefore more likely that H+ will be released
What do we form from further hydrolysis of metal-aqua ions
Insoluble metal hydroxides
What is the state of the neutral complex formed after repeated hydrolysis using OH- of metal aqua ions
Further hydrolysis leads to the formation of a neutral complex that is solid and forms precipitate in solution
Write the equations for the 3 stages for the formation of a solid metal hydroxide precipitate from the hydrolysis of (M(H2O)6)3+(aq)
M = Al3+ and Fe3+
(M(H2O)6)3+(aq) + H2O(l) ⇌ (M(H2O)5(OH))2+(aq) + H3O+(aq)
(M(H2O)5(OH))2+(aq) + H2O(l) ⇌ (M(H2O)4(OH)2)+(aq) + H3O+(aq)
(M(H2O)4(OH)2)+(aq) + H2O(l) ⇌ M(H2O)3(OH)3(s) + H3O+(aq)
Why are there only two steps to form an insoluble solid from metal aqua 2+ ions rather than 3 for metal aqua 3+ ions
Only two water ligands need to be deprotonated to form a neutral complex
Write the equations for the 2 stages for the formation of a solid metal hydroxide precipitate from the hydrolysis of (M(H2O)6)2+(aq)
M = Cu2+ and Fe2+
(M(H2O)6)2+(aq) + H2O(l) ⇌ (M(H2O)5(OH))+(aq) + H3O+(aq)
(M(H2O)5(OH))+(aq) + H2O(l) ⇌ M(H2O)4(OH)2(s) + H3O+(aq)
Which way does equilibrium shift when we add OH- ions to the reaction between a metal aqua ion and water
Equilibrium shifts right
Metal hydroxides can act as an acid or base meaning they are….
Amphoteric
What is a Bronsted lowry base
H+ acceptor
What is a Bronsted lowry acid
H+ donor
Give an example of an amphoteric metal hydroxide
Al(H2O)3(OH)3
What is the equation for when aluminium hydroxide reacts with a excess base
Al(H2O)3(OH)3(s) + OH-(aq) —> (Al(H2O)2(OH)4)-(aq) + H2O(aq)
How does aluminium hydroxide act when we add a base
Acts as a Bronsted lowry acid to react with the OH- and therefore it dissolves
How does aluminium hydroxide act when we add an acid
Acts as a Bronsted lowry base by accepting H+ ions to form H3O+ in solution and therefore it dissolves
What is the equation for when aluminium hydroxide reacts with an acid
Al(H2O)3(OH)3(s) + 3H3O+(aq) —> (Al(H2O)6)3+(aq) + 3H2O(aq)
What do we form when we add small amounts of ammonia to metal aqua ions
Metal hydroxide precipitates
Write the equation showing the equilibrium as to how ammonia exists in solution
NH3(aq) + H2O(l) ⇌ NH4+(aq) + OH-(aq)
What sometimes occurs when we add excess ammonia to metal aqua ions
A partial ligand substitution
What is the equation for when copper hydroxide reacts with excess ammonia
Cu(OH)2(H2O)4(aq) + 4NH3(aq) —> (Cu(NH3)4(H2O)2)2+(aq) + 2OH-(aq) + 2H2O(l)
What do we form when we add sodium carbonate to 2+ metal aqua ions
Insoluble metal carbonate precipitates
What is the general equation for when we add a carbonate to 2+ metal aqua ions
(M(H2O)6)2+(aq) + CO32-(aq) ⇌ MCO3(s) + 6H2O(l)
Why do we not form a carbonate when we add sodium carbonate to 3+ metal aqua ions
3+ metal ions are more acidic than 2+ and there is more H3O+ ions in solution
Carbonate ions react with the free H3O+ ions instead of displacing water ligands like 2+ ions
What is the general equation for when we add a carbonate to 3+ metal aqua ions
2(M(H2O)6)3+(aq) + 3CO2-(aq )⇌ 2M(OH)3(H2O)3(s) + 3CO2(g) + 3H2O(l)
What is observed when we add sodium carbonate to 3+ metal aqua ions
Fizzing
(due to CO2 produced)
What is observed when we add NaOH to Fe2+ Cu2+ Al3+ and Fe3+
All react to form precipitates
State and explain what is observed when we add excess NaOH to an aluminium hydroxide precipitate
It dissolves as it is amphoteric
White precipitate to a colourless solution
What is observed when we add NH3 to Fe2+ Cu2+ Al3+ and Fe3+
All react to form precipitates
When adding NaOH to Fe2+ Cu2+ Al3+ and Fe3+, a precipitate is formed. Which is the only precipitate that dissolves in excess NaOH
Aluminium hydroxide
When adding NH3to Fe2+ Cu2+ Al3+ and Fe3+, a precipitate is formed. Which is the only precipitate that dissolves in excess NH3
Copper Hydroxide
State and explain what is observed when we add excess NH3 to a Copper Hydroxide precipitate
Dissolves as there is a ligand substitution
Colour goes from pale blue precipitate to dark blue solution
(pale blue precipitate dissolves to form a dark blue solution)
What is observed when we add Na2CO3 to Fe2+ Cu2+ Al3+ and Fe3+
All react to form precipitates
What is observed when Al3+ and Fe3+ react with sodium carbonate
A precipitate and bubbles (CO2 formed)
Do we produce a gas when Cu2+ and Fe2+ react with sodium carbonate
No, only a precipitate is formed
Why must any Fe2+ solution being tested be made fresh
Fe2+ oxidises readily with air to form Fe3+
What colour is Cu2+(aq)
Blue
What colour is observed when we add small amounts of OH-(aq) or NH3(aq) to Cu2+(aq)
Pale blue precipitate
What colour is observed when we add excess OH-(aq) to the precipitate formed from adding small amounts of OH-(aq) to Cu2+(aq)
No change
Insoluble in excess NaoH
What colour is observed when we add excess NH3(aq) to the precipitate formed from adding small amounts of NH3(aq) to Cu2+(aq)
Dark blue solution
What colour is observed when we add Na2CO3(aq) to Cu2+(aq)
Green - Blue precipitate
What colour is Fe2+(aq)
Pale green
What colour is observed when we add small amounts of OH-(aq) or NH3(aq) to Fe2+(aq)
Dirty green precipitate
What colour is observed when we add excess OH-(aq) to the precipitate formed from adding small amounts of OH-(aq) to Fe2+(aq)
No change
Insoluble in excess NaoH
What colour is observed when we add excess NH3(aq) to the precipitate formed from adding small amounts of NH3(aq) to Fe2+(aq)
No change
Insoluble in excess NH3
What colour is observed when we add Na2CO3(aq) to Fe2+(aq)
Green precipitate
What colour is Fe3+(aq)
Yellow
What colour is observed when we add small amounts of OH-(aq) or NH3(aq) to Fe3+(aq)
Orange precipitate
What colour is observed when we add excess OH-(aq) to the precipitate formed from adding small amounts of OH-(aq) to Fe3+(aq)
No change
Insoluble in excess NaoH
What colour is observed when we add excess NH3(aq) to the precipitate formed from adding small amounts of NH3(aq) to Fe3+(aq)
No change
Insoluble in excess NH3
What colour is observed when we add Na2CO3(aq) to Fe3+(aq)
Brown precipitate
What colour is Al3+(aq)
Colourless
What colour is observed when we add small amounts of OH-(aq) or NH3(aq) to Al3+(aq)
White precipitate
What colour is observed when we add excess OH-(aq) to the precipitate formed from adding small amounts of OH-(aq) to Al3+(aq)
Colourless solution
What colour is observed when we add excess NH3(aq) to the precipitate formed from adding small amounts of NH3(aq) to Al3+(aq)
No change
What colour is observed when we add Na2CO3(aq) to Al3+(aq)
White precipitate
Draw the table for colours of the ions Cu2+, Fe2+, Fe3+, Al3+
What is the the equation for adding drops (not excess) of OH- to (Al(H2O)6)3+
What ion does NH3 form
NH4+
Write the colour observed, final species and equation when (Cu(H2O)6)2+ reacts with concentrated HCl
Draw the routes for Fe
Draw the routes for Cu
Draw the routes for aluminium