Catalonia PAU Chemistry case studies
Catalonia PAU Chemistry · Put your knowledge to work in context.
La Química és una de les matèries de modalitat de les Proves d'Accés a la Universitat (PAU) a Catalunya, el conjunt d'exàmens que l'alumnat fa en acabar el batxillerat per accedir a estudis universitaris i, en la fase específica, per millorar la nota d'admissió en graus concrets. És per a estudiants de segon de batxillerat que han cursat Química com a matèria de modalitat i volen entrar en graus com Química, Farmàcia, Biotecnologia, Medicina, Enginyeria Química o Ciències Ambientals, on aquesta assignatura pondera en la nota d'accés. The Catalonia PAU Chemistry case studies are 5 cases and about 3,860 words.
1The Buffer That Tested Below Tolerance
A final-year student in a Tarragona analytical laboratory must prepare 0.500 L of a pH 4.70 buffer with an acceptance window of 4.60–4.80 for a spectrophotometric assay. Only glacial acetic acid (Mr 60.05) and sodium acetate trihydrate (Mr 136.08) are available, and pKa(CH3COOH) = 4.74.
708 words, about 4 min2Copper Recovery Before Discharge
A printed-circuit workshop in Rubí treats 2.0 L of spent etchant containing CuSO4 0.150 M and H2SO4 0.020 M by electrodeposition onto a graphite cathode before the liquor goes to waste. The rectifier delivers a constant 3.00 A, the current efficiency for copper deposition is 94%, and a 90.0 min run is scheduled.
785 words, about 4 min3Iodine Clock That Ignores the Iodine
A university laboratory in Barcelona studies the acid-catalysed iodination of propanone at 298 K by following the fading of the yellow-brown iodine colour in a spectrophotometer. The stock solutions are propanone 1.00 M, HCl 1.00 M and I2 0.0200 M; the ionic strength is kept constant with KCl.
763 words, about 4 min4Lime Kiln Below the 'Decomposition Temperature'
A lime producer in the Penedès feeds 12.0 t h⁻¹ of limestone (98.0% CaCO3, Mr 100.09) into a rotary kiln at 1100 K, fired with natural gas. Part of the off-gas is recycled, so the CO2 partial pressure inside the kiln is held at 0.30 atm.
785 words, about 4 min5The Unknown With Formula C4H8O2
An undergraduate practical in Girona issues an unknown colourless liquid with molecular formula C4H8O2 (Mr 88.11) and boiling point 163 °C; the student must decide whether it is a carboxylic acid or an ester before the session ends. Available reagents are 0.100 M NaOH, phenolphthalein, aqueous NaHCO3 and an IR spectrometer.
819 words, about 4 min