Inorganic Chemistry Flashcards
(32 cards)
How do you test for carbonate ions in a solution?
Add acid, carbon dioxide will be produced if it’s a positive test, you can see if carbon dioxide is produced by bubbling the gas produced through lime water, which will go cloudy if positive.
What are the trends for group 2?
Get more reactive going down⬇️
Atomic radius increases going down the group due to increased energy levels ⬇️
First ionisation energy increases going up ⬆️
So atomic radius is a larger factor.
What are the trends in melting point for group 2?
Radius of metal ions increases going down ⬇️
Charge density increases going up ⬆️
Force of attraction between metal ions and delocalised electrons increases going up ⬆️
(reduces strength of metallic bonding)
Why is magnesium anomalous in the group 2 melting trend?
It has a different metallic structure to beryllium.
What happens when Beryllium is heated in the presence of water?
Nothing, beryllium doesn’t react with water. 😕
What is produced when magnesium reacts with water?
Magnesium hydroxide and hydrogen
Describe the reaction of magnesium with water.
Very slow
Magnesium hydroxide isn’t very soluble so leaves ppt
Describe the reaction and the products produced when calcium reacts with water.
Steady reaction with water
Ca(OH)2 and H2 produced
Ca(OH)2 is slightly soluble leaving cloudy alkaline solution
Describe the reaction between Strontium and water.
Quick
Exothermic
Describe the products of strontiums reaction with water.
Sr(OH)2 soluble forming cloudy alkaline solution
Stored in oil to prevent reinformation
Explain the reaction between barium and water.
Same as strontium and water but quicker and better…
Explain the trend in solubility for alkaline metal hydroxides.
Increases going down the group ⬇️
Explain the trend in alkaline metal sulphates.
Add application
Becomes more soluble going up ⬆️
Barium is good at absorbing x-Rays so can be used to outline the gut
Considering the trend with ionisation energies with group 2, how does this affect the shielding ability of the shells?
It means that the inner shells are more effective at shielding the nucleus.
What happens to group2 in redox reactions?
They’re oxidised
Where is the name of alkaline metals derived?
Their oxides and hydroxides are alkaline.
Most metals found in the earth are oxides, how are they extracted?
They are extracted in a displacement reaction with carbon.
This produces the metal and carbon dioxide.
Why can Titanium not be displaced from titanium oxide using carbon?
Titanium carbide would be produced with is a very brittle metal.
How is titanium removed from titanium oxide?
First it reacts with chlorine and carbon to make TiCl4 and CO.
Next TiCl4 is reduced to titanium by reacting it with magnesium making 2MgCl2 and Ti!
How do the trends with hydroxides and sulphates work for solubility in group 2?
Hydroxides - solubility increases going down.
Sulphates - solubility increases going up.
How can barium sulphate be used to detect sulphate ions?
1) Solution acidified with nitric acid.
2) Barium chloride solution is added to the solution
3) If a sulphate ion is present a white precipitate is formed
- You can add acid to remove the carbonate ions
How do you test for chloride, bromide and iodide ions?
1) Add dilute nitric acid and silver nitrate solution to your solution.
2) If chlorine ions are present, a white ppt is formed
If bromine ions are present, a cream ppt is formed
If iodide ions are present, a yellowish ppt is formed
How can you distinguish between silver bromide ions and silver chloride ions?
1) Add an excess of dilute aqueous ammonia solution, if chloride ions are present, the ppt will redissolve.
2) Add an excess of concentrated ammonia solution, if bromide ions are present, the ppt will redissolve.
Explain a trend in appearance for the halogens.
They become darker and denser going down the group.
