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WorksheetsQuiz 4 : Gravimetry and Volumetry Analysis
Total questions: 20
Worksheet time: 25mins
What would happen to the weighed mass if some precipitate seeped through the filter paper?
mass would be too high
molar mass would be too low
There would be no effect on the molar mass
The mass of the precipitate collected would decrease
If a student forgot to cover their experiment with parafilm over the weekend before they filtered their product, how would that affect the calculated molar mass?
molar mass would be too low
molar mass would be too high
molar mass would be unaffected
molar mass would certainly double
If you failed to heat the crucible enough times for the masses to be consistent, why would that cause your calculated molar mass to be too high?
the presence of water causes the mass of the unknown carbonate to be too high
the moles of calcium carbonate increases
the mass of the unknown carbonate will be too low
the moles of the unknown carbonate will be too high
25.0 cm3 of sodium hydroxide solution is tritrated against 0.200 mol dm–3 hydrochloric acid until the indicator just changes colour. 27.5 cm3 of the acid are required to reach the end point.
Phenolphthalein is used as an indicator in the above experiment. What will be its colour change at the end point?
From red to yellow
From red to colourless
From yellow to colourless
From yellow to red
To prepare a solution of accurately known volume, use a
measuring cylinder
beaker
concial flask
volumetric flask
A standard solution is a solution with accurately known concentration.
True
False
The point in an acid-alkali titration at which the reactants just react completely with each other is called the __________ point.
end point
equivalence point
__________ is a suitable indicator for the titration of a strong acid and a weak alkali.
Methyl orange
Phenolphthalein
Litmus solution
Universal indicator
During a titration, the end point and the equivalence point always occur at the same time.
True
False
20 cm3 of 1 mol dm–3 CH3COOH(aq) and 10 cm3 of 1 mol dm–3 H2SO4(aq) require the same number of moles of NaOH for complete neutralization.
True
False
Whats a conjugate acid-base pair, according to Brønsted-Lowry theory.
Differ by 1 proton
A substance that is monobasic
A substance that will dissociate easily
A substance(S) that don't dissociate easily
Convert 0.37g/l to ppm (mg/l)
370 ppm
37 ppm
0.00037
Gravimetric analysis is a (a) analysis based on the measurement of mass of a pure compound where the analyte targeted is chemically related
Solubility of precipitates is one of the factor that influences the properties of precipitate. How does it affect the properties?
Higher value of Ksp will lead to higher stability of precipitate
Lower value of Ksp is needed to reduce the chance of solubility of precipitates
Higher solubility of precipitate is required in order to have a good stability of precipitate
Good solubility of product indicates the good quality of precipitates formed
Precipitating reagents are needed in gravimetric analysis. Which are the Inorganic Reagents from the list below?
Silver Nitrate
Oxine
Barium Chloride
DMGH
The particle size or precipitates can be controlled during gravimetric analysis. How to minimise the relative supersaturation phenomenon?
The value of Q must be high
Q - S value must be high
The value of S must be low
Q - S value must be low
How did the impurities occur on top of the desired precipitates?
Co-precipitation
Post-precipitation
Back-precipitation
Pre-precipitation
Which are the methods to minimise the adsorbed impurities on precipitates surface?
Reprecipitation
Burning
Washing
Digestion
In gravimetric methods, after the heating process is done, precipitates have to be cooled down in a (a) before weighing in order to avoid humidities from entering the precipitates
Solid sodium hydroxide CANNOT be weighed accurately for preparing a standard solution because
it is corrosive.
it is volatile.
it decomposes easily.
it absorbs moisture from the air.
