Ions in Solids and Solutions
Chemistry F332 Notes
Ions in solids and solutions:
Structure of an ionic lattice (Sodium Chloride): * Consists of sodium ions (Na+) surrounded by six chloride ions (Cl-) * Chloride ions also surrounded by six sodium ions. * Held together by attraction of oppositely charged ions. * Giant ionic lattice. * Electrostatic bonds hold lattices together. * Structure is simple cubic. * Some ionic crystals contain water. * Known as water of crystallisation. * These crystals are hydrated. * Blue copper sulphate crystals are the pentahydrate crystals – CuSO4.5H2O * If there is no water of crystallisation then the ionic crystal is said to be anhydrous.
Ionic substances in solution: * Many dissolve in water without difficulty. * Ions become surrounded by polar water molecules. * They spread out through the solution. * Hydrated ions are randomly arranged and behave independently. * Positive hydrogen atoms in water are attracted to negative ions. * Conversely the negative oxygen atoms are attracted to positive ions. * This is known as hydration. * Draw water molecules as wedges and ion as a circle. * Label the charged ends.
Ionic equations: * All nitrates are soluble in water. * All chlorides are soluble in water bar AgCl and PbCl2. * All sulfates are soluble in water bar BaSO4, PbSO4 and SrSO4. * All sodium, potassium and ammonium salts are soluble in water. * All carbonates are insoluble in water bar (NH4)2CO3 and those of group 1. * The ionic equation for a neutralisation reaction is always – H+(aq) + OH-(aq) → H2O(l) * When writing an ionic equation label the charges on each ion then remove the spectator ions (like ions in charge and state and on both sides of equation). * If there is a precipitation reaction one product will be a solid. * With neutralisation reacts a covalent compound is formed.
Atoms and ions:
First ionisation enthalpy: * Energy
Ions in solids and solutions:
Structure of an ionic lattice (Sodium Chloride): * Consists of sodium ions (Na+) surrounded by six chloride ions (Cl-) * Chloride ions also surrounded by six sodium ions. * Held together by attraction of oppositely charged ions. * Giant ionic lattice. * Electrostatic bonds hold lattices together. * Structure is simple cubic. * Some ionic crystals contain water. * Known as water of crystallisation. * These crystals are hydrated. * Blue copper sulphate crystals are the pentahydrate crystals – CuSO4.5H2O * If there is no water of crystallisation then the ionic crystal is said to be anhydrous.
Ionic substances in solution: * Many dissolve in water without difficulty. * Ions become surrounded by polar water molecules. * They spread out through the solution. * Hydrated ions are randomly arranged and behave independently. * Positive hydrogen atoms in water are attracted to negative ions. * Conversely the negative oxygen atoms are attracted to positive ions. * This is known as hydration. * Draw water molecules as wedges and ion as a circle. * Label the charged ends.
Ionic equations: * All nitrates are soluble in water. * All chlorides are soluble in water bar AgCl and PbCl2. * All sulfates are soluble in water bar BaSO4, PbSO4 and SrSO4. * All sodium, potassium and ammonium salts are soluble in water. * All carbonates are insoluble in water bar (NH4)2CO3 and those of group 1. * The ionic equation for a neutralisation reaction is always – H+(aq) + OH-(aq) → H2O(l) * When writing an ionic equation label the charges on each ion then remove the spectator ions (like ions in charge and state and on both sides of equation). * If there is a precipitation reaction one product will be a solid. * With neutralisation reacts a covalent compound is formed.
Atoms and ions:
First ionisation enthalpy: * Energy