Chem Unit 2 definitions (syllabus)

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Chem Unit 2 definitions (syllabus)
2014-06-16 17:13:57
Definitions Chemistry unit

Syllabus definitions
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  1. Define the rate of reaction
    Change in concentration of a reactant or product per unit time
  2. Define the order of a reactant with respect to a reaction
    The power to which the concentration of the reactant is raised in the rate equation.
  3. Define Rate Constant
    The constant that links the rate of reaction with the concentrations of the reactants raised to the power of their orders in the rate equation
  4. Define the half life of a reaction
    The half life of a reactant is the time taken for the concentration of that reactant to reduce by half.
  5. Rate determining step
    The slowest step in the reaction mechanism of a multi - step reaction.
  6. Define an acid
    A proton donor
  7. Define a base
    A proton acceptor
  8. Define the term conjugate acid - base pair
    A pair of two species that transform into each other by gain or loss of a proton.
  9. Difference between a strong and weak acid
    A strong acid almost completely dissociates, a weak acid partially dissociates
  10. Define a buffer solution
    System that minimises pH changes on addition of small amounts of an acid or a base
  11. What is meant by lattice enthalpy?
    The enthalpy change that accompanies the formation of one mole of an ionic compound from its gaseous ions under standard conditions.
  12. What is meat by enthalpy change of solution?
    Enthalpy change that takes place when one mole of a compound is completely dissolved in water under standard conditions.
  13. Define the enthalpy change of hydration
    Standard enthalpy change that takes place when one mole of isolated gaseous ions is dissolved in water forming one mole of aqueous ions under standard conditions
  14. Define entropy
    The quantitative measure of disorder in a system.
  15. Define redox
    A reaction in which both oxidation and reduction take place
  16. Define oxidation no.
    A measure of the number of electrons that an atom uses to bond with atoms of another element.
  17. Define oxidising agent
    A reagent that oxidises another species (takes electrons)
  18. Define reducing agent
    A reagent that reduces another species (gives electrons)
  19. Define standard electrode potential
    The emf of a half cell compared with a standard hydrogen half cell measure at 298K with solution concentrations of 1mol/dmĀ³ and a gas pressure of 100kpa
  20. What is meant by a transition metal element?
    A d-block element which forms an ion with an incomplete d sub - shell
  21. What is a ligand?
    A molecule or ion that can donate a pair of electrons with the transition metal ion to form a coordinate bond.
  22. What is a complex ion?
    A transition metal ion bonded to one or more ligands by coordinate bonds (dative covalent bonds)
  23. Explain what is meant by coordination no.
    The total number of coordinate bonds formed between the central metal ion and any ligands.
  24. Explain the term bidentate ligand
    When a ligand can donate two lone pairs of electrons to the central metal ion to form two coordinate bonds.
  25. Define ligand substitution
    A reaction in which one ligand in a complex ion is replaced by another ligand.
  26. Define Stability constant
    The equilibrium constant for an equilibrium existing between a transition metal ion surrounded by water ligands and the complex formed when the same ion has undergone a ligand substitution reaction.
  27. Define enthalpy change of neutralisation
    Enthalpy change that occurs for the formation of 1 mole H2O from reaction of an acid with an alkali/base