Inorganic 2 Section 2 - Unit 22: Periodicity
No description yet. This curated deck is ready for daily study.
Card preview (24)
Deduce the type of bonding in phosphorus oxide (1 mark)
Simple molecular
Write an equation for the reaction between phosphorus oxide and water (1 mark)
P₄O₁₀ + 6H₂O → 4H₃PO₄
State the meaning of the term amphoteric (1 mark)
Reacts with acids and bases
Explain why sodium oxide forms an alkaline solution when it reacts with water (2 marks)
• Sodium oxide contains O²⁻ ions - Which react with water forming OH– ions
Write two equations to show the amphoteric nature of aluminium oxide (2 marks)
Al₂O₃(s) + 2OH⁻ (aq) + 3H₂O (l) → 2Al(OH)₄ (acid) Al₂O₃ + 6H+ → 2Al³⁺ + 3H₂O
Write an ionic equation for the reaction of phosphorus(V) oxide with an excess of sodium hydroxide solution (1 mark)
P₄O₁₀ + 12OH⁻ → 4PO₄³⁻ + 6H₂O
Describe what you would observe when magnesium is heated with steam (2 marks)
• White solid - White light / flame
Describe what you would observe when sodium is heated in oxygen (2 marks)
• White solid - Yellow flame
State the observation when magnesium reacts with oxygen (2 marks)
• Burns with a white flame - To give a white solid smoke
State the observation when aluminium reacts with oxygen (2 marks)
• Burns with a white flame - To give a white solid smoke
State the observation when silicon reacts with oxygen (2 marks)
• Burns with a white flame - To give a white solid smoke
State the observation when phosphorus reacts with oxygen (2 marks)
• Burns with a white flame - To give a white solid smoke
State the observation when sulfur reacts with oxygen (2 marks)
• Burns with a blue flame - To produce an acidic choking gas
Explain why aluminium oxide shows some covalent character as well as ionic character (2 marks)
• Small aluminium ion has high charge (3+) so pulls the electrons from O²- towards itself • This distorts the oxide charge cloud and creates covalent character
Suggest why P₄O₁₀ and SO₂ are simple covalent oxides (1 mark)
• Small electronegativity difference between the non-metal and the O atoms
Suggest and explain how aluminium metal is protected from corrosion in moist air (3 marks)
• Thin layer of aluminium oxide • As it has a high lattice strength and is insoluble in water • So makes this layer impermeable to air and water
State the pH of the solution formed when sodium oxide reacts with water and explain why it has this pH (2 marks)
• pH 13 - Oxide ions accept protons and become hydroxide ions
State the pH of magnesium hydroxide and suggest why it is lower than the pH of sodium hydroxide (3 marks)
• pH 9 • It’s lattice is stronger so it is only slightly soluble in water • So fewer OH- ions are produced
State the pH of the solution formed when phosphorus oxide reacts with water (1 mark)
• pH 0
State the pH of H₂SO₃ (1 mark)
pH 3
State the pH of H₂SO₄ (1 mark)
pH 0
State the ionic equation in which aluminium oxide acts as a base (1 mark)
Al₂O₃ + 6H+ –> 2Al³+ + 3H₂O
State the ionic equation in which aluminium oxide acts as an acid (1 mark)
Al₂O₃ + 2OH- + 3H₂O –> 2Al(OH)₄-
Explain why magnesium has a higher melting point than sodium (2 marks)
• Magnesium has a higher charge - So delocalised electrons pulled in more closely