C4- Acids and Redox Flashcards
What is an acid
An acid is a proton (H+ ion) donor
What is a base
A proton (H+) acceptor
Acid in water
When an acid is added to water it dissociates releasing H+ ions into solution
Strong Acid
An acid that fully dissociates in solution
Weak acid
An acid that partially dissociates in solution
Alkali
base that dissolves in water releasing OH- ions into solution
Bases examples
4
metal oxides
Metal carbonates
Metal hydroxides
Ammonia
Dissociation of strong vs weak acid Equation
Reversible for weak single for strong
Equilibrium lies to the left for weak acid as not fully ionised
Writing an ionic equation
Full balanced equation
Expand all ions
NOT solids
Cancel out same ions
Form ionic equation
Method to make a standard solution
Weigh out a precise amount of a solid
Dissolve solid in beaker with distilled water, less than what will be made up in the volumetric flask
Transfer to volumetric flask
Fill to graduation line using distilled water, until the bottom of the meniscus lines up
Invert several times to mix the solution
Titration procedure
Add a measured volume of one solution to a conical flask
Add the other solution to a burette, record its initial reading
Add a few drops of indicator to the conical flask
The tap on the burette is carefully opened and the solution added, portion by portion, to the conical flask until the indicator starts to change colour
As you start getting near to the end point, the flow of the burette should be slowed right down so that the solution is added dropwise
Multiple runs are carried out until concordant results are obtained
–>Concordant results are within 0.1 cm3 of each other
Percentage uncertainty
per reading
uncertainty/ measured value x100
burette reading
Since they are analogue instruments, the uncertainty is recorded to half the smallest marking, in other words to ±0.05 cm3
Read to the nearest half division
