STPM Chemistry 962 case studies
STPM Chemistry 962 · Put your knowledge to work in context.
STPM Chemistry 962 is the Chemistry subject of Sijil Tinggi Persekolahan Malaysia, the post-SPM pre-university qualification administered by Majlis Peperiksaan Malaysia (MPM). It is taken by students seeking a recognised route into university science, medicine, pharmacy, engineering and education programmes, and it is widely accepted for admission to Malaysian public universities and many institutions abroad. The STPM Chemistry 962 case studies are 5 cases and about 4,668 words.
1The Spreadsheet With One Wrong Number: Assigning an Element from Successive Ionisation Energies
A metrology trainee is checking a spreadsheet of successive ionisation energies (kJ mol⁻¹) for an unidentified Period 3 element X used to calibrate an atomic absorption spectrometer. The listed values are: 738, 1451, 7733, 10543, 1363 , 17995, 21703, 25666, 31670, 35460 The trainee's supervisor typed the fifth entry "from memory" after the printout jammed, and the raw instrument file cannot be reopened until Monday.
855 words, about 4 min2Two Isomers, One Distillable: Separating 2- and 4-Nitrophenol
A second-year laboratory class nitrates phenol and obtains 2.1 g of a dark mixture that TLC shows to be two products. The demonstrator insists on steam distillation rather than column chromatography, because the column is booked by another group.
951 words, about 5 min3Spirit Burners and Cost per Megajoule: Choosing a Camping Fuel
A hillwalking club wants to move away from methylated-spirit stoves and asks a chemistry student to compare ethanol and butan-1-ol as fuels. The student burns each fuel in a spirit burner under a copper can holding 150 g of water, using a draught shield and continuous stirring.
1,002 words, about 5 min4Molecular Sulfur Dioxide in a White Wine: Add Sulfite or Lower the pH?
A small winery holds 4 500 dm³ of dry white wine at pH 3.75, with 32 mg dm⁻³ free SO₂ measured by Ripper titration and 95 mg dm⁻³ total SO₂. The winemaker wants at least 0.8 mg dm⁻³ of molecular SO₂ - the uncharged form that actually inhibits yeasts and bacteria.
939 words, about 5 min5Extrapolating a Shelf Life: A Reconstituted Antibiotic Suspension
A hospital pharmacy prepares a reconstituted oral antibiotic suspension labelled "store in a refrigerator; discard 14 days after reconstitution". A pharmacist is asked whether a longer refrigerated shelf life could be justified.
921 words, about 5 min