Chapter 4: Acids And Redox (4.1-4.3) Flashcards
What is the difference between a strong and a weak acid?
A strong acid completely dissociates in solution and released all its hydrogen atoms into solution but a weak acid only partially dissociates and releases some of its H+ atoms into solution.
What happens when you add a base and an acid?
The base neutralises the acid to form a salt and water.
What happens in neutralisation in terms of ions?
The H+ ions from the acid are replaced by metal or ammonium ions from the base.
What is the ionic equation of reacting an acid with an alkali? I’m
H+(aw) + OH-(aq) -> H2O (l)
What does a metal carbonate neutralise an acid to form?
Salt, water and carbon dioxide
How do you make a standard solution?
1) Weigh solid
2) Dissolve solid in distilled water below the mark
3) Transfer solution to volumetric flash (RINSE THE BEAKER WITH DISTILLED WATER)
4) Fill flask to graduation line with distilled water (AVOID PARALLAX ERROR)
5) INVERT VOLUMETRIC FLASK SEVERAL TIMES - mixes solution
How many decimal places does a burette reading have?
It is measured to the nearest 0.05, so it has to be either a 0 or 5 and has to be measured to 2 decimal places.
Describe the procedure of an acid base titration
1) Add 25cm[3] (pipette) of alkali to conical flask
2) Add acid to burette and measure reading
3) Add indicator to the conical flask
4) Run the acid into the alkali until the indicator changes colour
5) Record the final burette reading
6) Quick trial titration to get approximate titre
7) Repeated accurately, adding solution dropwise we end point approaches until two accurate titres are concordant.
When is the oxidation number 0?
In a pure element
How do you work out total charge of a combined atom?
Sum of the oxidation numbers
How do you know the oxidation number of the ion of an element ?
It is the same as the ionic charge but the sign comes before the number
What is the oxidation number of H in metal hydrides?
-1
What is the oxidation number of O in peroxides?
-1
What is the oxidation number of O when bonded to F?
+2
What do the Roman numerals in compounds mean?
The oxidation number of the element you don’t know the oxidation number of.