Inorganic Chemistry and Periodic Table Flashcards
How does the solubility of hydroxides change down group 2?
it INCREASES down the group (Mg(OH)2 is almsot insoluble)
How does sulfate solubility change DOWN group 2?
Magnesium sulfate is classed as soluble and barium/strontium sulfate is classed as inspluble
- So solubility decreases.
How does magnesium react with water and steam differently?
Mg reacts slowly with water but VERY vigorously when heated in steam.
What is the test for sulfate ions?
- add solution of soluble BARIUM compound to something containing SO42- ions
- BaSO4 will form and precipitate.
What is thermal decomposition?
the breaking down of a compound into different products (usually only complex ions do this)
What is the origin of flame tests?
- electrons move to higher, unoccupied energy levels when heated.
- when this energy is lost, they return to their original energy levels (ground state) and release energy waves.
- energy waves in forms of visible light.
Why do some elements not produce positive light tests?
- they don’t produce wavelengths that correspond to visible ligth waves
How do you carry out flame tests?
- clean nicrome/platinum wire by dipping in conc. HCl acid and burn off in cone of blue Bunsen flame.
- dip in conc, HCl acid and then in metal compound
- burn in cone of blue Bunsen flame and observe colour given off
What are the colours of the flame tests you need to know?
Barium: apple green
Strontium: crimson red
Calcium: brick red
Caesium: blue/violet
Rubidium: red/purple
Potassium: lilac
Sodium: yellow/orange
Lithium: red
What colour is bromine in different states?
- brown LIQUID
- red-brown GAS
(is poisonous and corrosive)
What colour is chlorine in different states?
- green/yellow GAS
( toxic)
What colour is iodine in different states?
- grey/silver SOLID
- violet LIQUID
- purple GAS
What is the test for halide ions?
- add silver nitrate solution
chloride ions: white precipitate
bromide ions: cream precipitate
iodide ions: yellow precipitate
