Task 3 Flashcards
(31 cards)
Arrhenius limitations
Applies only to aqueous solutions
Cannot explain basic and acidic nature of salts
Cannot explain amphiprotic substances
Does not recognise role of water as solvent
Cannot explain bases without OH-
BL theory proves
Acid base reactions are not limited to aqueous solutions –> proton tranfer in gaseous phases
Conjugate bases and acids
Amphiprotic nature of water as solvent
BL theory limitations
Cannot explain acidic basic oxides and amphoteric substances
End point
the point during a titration when the indicator first produces a permanent colour
Pipette
used to transfer a specific volume of either the standard solution or unknown solution to the conical flask
Burette
providing precise liquid measurement and dispensing
Primary standards
pure substance, high molar mass, stable, soluable, easy to store
Methyl orange ph range
colours
3.1-4.4
red-orange-yellow
bromothymol blue ph range
colours
6.0-7.6
yellow-green-blue
phenolpthalien ph range
colours
8.2-10.0
colourless-light pink-pink
neatralisation reactions
3
antacid tablets (Mg (OH)2 ) and HCl in stomach
Bases used to neutralise acid spills (Na2CO3) weak only
Toothpaste (NaF, NaOH) neutralises acids in mouth
buffer capacity
a measure of the effectiveness of a buffer solution at reissiting change in oH when either a strong acid or strong base is added
blood buffer equations
2
CO2 + H2O <-> H2CO3
H2CO3 + H2O <-> H3O+ + HCO3-
Importance of blood buffer
If ph deviates too much fro range, biological enzymes will denature
active site and shape will change, unable them to catayle metabolic processes in body
Hydrocarbon safety handles
Dispose in waste container due to toxicity to aquatic life
No nakes flames due to flammability, handle in fume cupbaord
Used in well ventilaisted space so no inhalation occurs
Flame colour for Na
Yellow
Flame colour for K
Lilac
Flame colour for Li
Crimson red
Reasons for analysing ions
agricultural run off/eutriphication of fertilisers like NH4NO3
Heavy metals from mines, landfill sites, combustion of fuels, wastes, agrocultural runoff
Example (Pu, Cu, Hg)
Grey water (sink and landry) –> PO4 in detergents
Port pirie case study
largest primary Pb smelter
Airborne lead contaminated dust
Damages nerous system, developing ones for children, permanent brain damage
Max blood conc of Pb
Average
Children in Port Pirie
5u/dl
1.45u/dl
8u/dl
Validity is
ACER
aim, constant, equip, range
aim achieved, constant variables, approptriate equipment to reduce error, suitable range
Reliability is
ROCA
repeat, outlier, consistent, average
repeated with large sample size, outliers removed, results consistent, averaged results
Accuracy is
SERC
scale, equipment, record, closeness
scale have sufficent graduations, equipment used correct, results recorded with decimal places, measurements close to theoretical values
