European Baccalaureate Chemistry case studies
European Baccalaureate Chemistry · Put your knowledge to work in context.
The European Baccalaureate (often shortened to EuroBac or EB) is the school-leaving credential awarded at the end of secondary schooling in the European Schools system. The Office of the Secretary-General of the European Schools in Brussels describes itself as the administrative body serving the European Schools, and its site lists the European Baccalaureate as an area of study alongside syllabuses, a marking scale and the organisation of studies. The European Baccalaureate Chemistry case studies are 5 cases and about 3,497 words.
1Identifying an element from ionisation energies and a mass spectrum
An unknown element X is investigated in two ways. A mass spectrum shows three peaks at m/z 24, 25 and 26 with relative abundances 79.0%, 10.0% and 11.0%.
710 words, about 4 min2Assigning dichloroethene isomers from dipole moments and boiling points
Three unlabelled samples of dichloroethene, C2H2Cl2, are labelled A, B and C. The only structural isomers are 1,1-dichloroethene, cis-1,2-dichloroethene and trans-1,2-dichloroethene.
693 words, about 3 min3Testing the ionic model for magnesium oxide with a Born–Haber cycle
A class is asked to evaluate the ionic model for magnesium oxide. The following thermodynamic data are provided in kJ mol−1: enthalpy of formation of MgO(s) = −602; enthalpy of atomisation of Mg(s) = +148; first ionisation energy of Mg = +738; second ionisation energy of Mg = +1451; enthalpy of atomisation of O2(g) to 2O(g) per mole of O atoms = +249; first electron affinity of O = −141; second electron affinity of O = +798.
664 words, about 3 min4Using initial rates to find a rate law and propose a mechanism
The oxidation of bromide by bromate(V) in acidic solution is studied at 25 °C: BrO3−(aq) + 5Br−(aq) + 6H+(aq) → 3Br2(aq) + 3H2O(l). A spectrophotometer is used to follow the absorbance of bromine at 400 nm, and initial rates are obtained from the tangent to the absorbance–time curve at t = 0.
756 words, about 4 min5Evaluating an aspirin synthesis by limiting reagent, yield and titration
A student prepares aspirin (acetylsalicylic acid, Mr = 180.16) by reacting salicylic acid (Mr = 138.12) with acetic anhydride (Mr = 102.09, density = 1.08 g cm−3). The student uses 2.00 g of salicylic acid, 5.0 cm3 of acetic anhydride and a few drops of concentrated sulfuric acid.
674 words, about 3 min