Pancyprian Chemistry case studies
Pancyprian Chemistry · Put your knowledge to work in context.
The Pancyprian Chemistry Examination (Παγκύπρια Εξέταση Χημείας) is a written subject examination used in Cyprus for candidates who need a verified chemistry qualification, typically for university admission or for demonstrating subject competence. It is aimed at upper-secondary students and other candidates who have completed a chemistry course at that level. The Pancyprian Chemistry case studies are 5 cases and about 3,037 words.
1Hydrogen collection over water and an alloy that is not pure magnesium
A 0.500 g sample of a magnesium-aluminium alloy is treated with 40.0 mL of 2.00 mol/L hydrochloric acid, which is in excess. The hydrogen produced is collected over water at 22.0 degC.
618 words, about 3 min2Initial rates, a suspicious termolecular step, and temperature
A student studies the bromate-bromide reaction in acidic solution: BrO3- + 5Br- + 6H+ - 3Br2 + 3H2O. The initial rate is measured colorimetrically at 25.0 degC by timing the first appearance of a fixed bromine concentration.
592 words, about 3 min3Weak-acid titration: which pH should be trusted?
A 25.00 mL sample of a monoprotic weak acid HA is titrated with 0.1000 mol/L sodium hydroxide using a calibrated pH meter. The equivalence point is reached after 22.40 mL of base.
659 words, about 3 min4Identifying an unknown metal from a cell potential
A student constructs a galvanic cell at 298 K from an unknown metal M dipping into 0.0100 mol/L M(NO3)2 solution and a silver electrode dipping into 0.100 mol/L AgNO3 solution. A potassium nitrate salt bridge connects the half-cells.
562 words, about 3 min5Ethyl ethanoate preparation: limiting reagent, equilibrium and purity
A student prepares ethyl ethanoate by refluxing 10.0 mL of ethanol (density 0.789 g/mL) with 10.0 mL of glacial ethanoic acid (density 1.05 g/mL) and 2.0 mL of concentrated sulfuric acid as catalyst. After reflux, the mixture is distilled, washed with water and saturated sodium hydrogencarbonate solution, dried over anhydrous sodium sulfate, and redistilled.
606 words, about 3 min