inorganic chem

• Hydroxides react with water to form?

  Hydroxide M(OH)2
• Hydroxides react with dilute acid to form?

  Salt MCl2 and water
• Explain why thermal stability increases down a group.

  As the ionic radius of the cation gets larger they cause less distortion of the anion, due to the lower charge density, thus more stable the carbonate/nitrate compound.
• Why are group 2 compounds less thermally stable than group1.

  They have a higher charge thus they cause greater distortion to the anion and the less stable the carbonate/nitrate compound becomes.
• Group 1 carbonates decompose to form?

  Nothing, they are thermally stable.

  Except from Lithium: Li2CO3- Li2O and CO2
• Which is the exception?

  Li2CO3- Li2O and CO2
• Group 1 nitrates decompose to form?

  Nitrite and oxygen MNO2 + O2
• Group 2 carbonates decompose to form?

  Oxide and carbon dioxide, MO + CO2
• Group 2 Nitrates decompose to form?

  Oxide, nitrogen dioxide and oxygen, MO + NO2 + O2
• How would you measure the thermal stability of nitrates?

  How long it takes for a certain amount of oxygen to be produced. Or the brown NO2 gas.
• How would you test the thermal stability of carbonates?

  How long it takes for carbon dioxide to be produced. Carbon dioxide bubbled through limewater turns it cloudy.
• Flame colour of Lithium

  RED
• Flame colour of sodium

  Orange/yellow
• Flame colour for potassium

  Lilac
• Flame colour for rubidium


  Red
• Flame colour for caesium

  Blue
• Flame colour for calcium

  Brick-red
• Flame colour of Strontium

  Crimson
• Flame colour of barium

  Green
• How would you carry out the flame test.

  Mix a small amount of the compound being tested with hydrochloric acid. Heat a platinum or nichrome wire in the blue part of the bunsen flame. Dip the wire into the solution and hold it in the blue part of the flame. Note colour produced.
• Why do we see colours in the flame test?

  The energy absorbed from the flame causes the electrons to move to higher energy levels. When the electrons fall back down to lower energy levels, releasing energy in the form of light. The difference between the higher and lower energy levels determines the wavelength of the light which determines the colour of the light.
• Explain the trend of reactivity down group 7,

  Down the groups, the atomic radius increases, their outer electrons are further away from the nucleus, and have more shielding. This makes it harder for larger atoms to attract the electron needed to form an ion, therefore larger ions are less reactive.
• Explain the trend in electronegativity down group 7.

  The increasing number of inner electron shell and the increase in distance between the nucleus and the bonding electrons reduces the atoms ability to attract the bonding pair of electrons.
• Explain the trend in melting and boiling points down the group.

  Increase. Increase in electron shells and therefore electrons, increasing the force of London forces, which become harder to overcome.
• Chlorine will displace...


  Both bromide and iodide ions.
• Bromine will displace...


  Iodide ions
• Iodide ions will displace...

  Neither chloride or bromide.
• What will happen if you mix the reaction mixture with an organic solvent like hexane?

  The halogen present will dissolve in the organic solvent, which settles out as a distinct layer.
• What colour is chlorine in water?

  Virtually colourless
• What colour is chlorine in hexane?

  Virtually colourless
• What colour is bromine in water?

  yellow/orange
• What colour is bromine in hexane?

  Orange/red
• What colour is iodine in water?

  Brown
• What colour is iodine in hexane?

  Pink/violet
• Halogens are examples of...

  Oxidising agents, they themselves are reduced (gain an electron) by oxidised other substances.
• Halogens react with group 1 and 2 to produce

  Halide salts.
• X2 + 2NaOH --> This is an example of...

  NaOX +NaX +H2O.... Disproportionation.
• What is bleach? And how is it made?

  Sodium chlorate solution. Reacting chlorine gas with cold, dilute aqueous sodium hydroxide.
• Another example of disproportionation...


  Halogens reacting with hot alkalis. NaXO3 + 5NaX + 3H2O
• Chlorine and water undergoes disproportionation too...


  Cl2 + H2O --> HCl + HClO