chapter 4

Question 1

strong acid

Answer 1

one which releases all its h+ ions into solution and completely dissociates in aq solution eg HCL

Question 2

weak acid

Answer 2

releases a sm:all proportion of ions. Partially dissociates in aq solution eg ethanoic

Question 3

alkali

Answer 3

a base that dissolves in water releasing hydroxide ions in solution

Question 4

neutralisation

Answer 4

acids are neutralised by metal oxides or metal hydroxides to form salt and water. carbonates also neutralise.

Question 5

preparing a standard solution

Answer 5

1) weigh solid
2) dissolve solid in beaker with distilled water
3) transfer solution to volumetric flask, using distilled water to transfer all traces
4) carefully fill to graduation lines that the bottom of the meniscus lines up exactly with the line
5) slowly invert the volumetric flask a few times to mix.

Question 6

acid base titration procedure

Answer 6

1) add the measured volume to the conical flask using a pipette
2) add the other solution to the burette and record the initial reading to the nearest 0.05cm3
3) add a few drops of indicator to the conical flask
4) run the solution in the burette into the flask, swirling to mix. the indicator changes colour at the end point of titration.
5) record the final burette reading- titre. calculated by subtracting the inital from the final.
6) a quick, trial titration is carried out first for an approximate titre
7) titration is repeated accurately, adding the solution dropwise until the end point is reached. Further titrations are carried out until two results are concordant ( within 0.1cm3)

Question 7

oxidation number rules

Answer 7

o = -2 H/F = +1

ions have the same oxidation number as their charge

Question 8

oxidation no special cases

Answer 8

• H in metal hydrides= -1
• O in peroxides= -1
• `O bonded to F= +2

Question 9

redox in terms of electrons & oxidation number

Answer 9

reduction = gain, decrease in oxidation no
oxidation = loss, increase