Chapter 4 ACIDS & REDOX

• What is an acid?

  A proton donor
• What is a base?

  A proton acceptor
• What is the different between a base and an alkali?

  Base: A substance that can accept a proton. Alkali: A base that dissolves in water to form hydroxide ions.
• What is the different between a strong acid and a weak acid?

  A strong acid fully dissociates and a weak acid partially

  dissoiates
• What is a titration?

  A technique to accurately measure the amount of a solution that reacts (neutralises) exactly with another solution
• What are titrations used for?

  Find the concentration or identify an unknown chemical
• When are titres concordant?

  If they are within 0.10cm3 of each other
• How is a standard solution prepared?

  250cm3 volumetric flask used

  1. Solid weighed accurately and dissolved in beaker with water
  2. Solution transferred to volumetric flask and filled just below the line
  3. Deionised water pipetted in until the meniscus touches the line
  4. Flask inverted several times
• What is important to do when preparing a standard solution?

  Rinse all equipment used with deionised water into the flask to ensure nothing is left behind
• What is the oxidation number of hydrogen in hydrides?

  -1
• What is the oxidation number of oxygen in peroxides?

  -1
• What is the oxidation number of oxygen bonded to fluorine and why?

  +2 because the most electronegative element takes priority always
• When is oxidation number of chlorine not -1?

  With fluorine and oxygen its +1
• What is a reduction reaction?

  Oxidation number decreases/gain of electrons/loss of oxygen
• What is an oxidation reaction?

  Increase in oxidation number/loss of electrons/gain of oxygen
• What is a disproportionation reaction?

  The same species is oxidised and reduced simultaneously
• What does the sum of oxidation numbers always have to equal?

  The overall charge
• What is meant by the term standard solution?

  A solution of known concentration