Armenia Chemistry Unified Exam case studies
Armenia Chemistry Unified Exam · Put your knowledge to work in context.
The Chemistry Unified Exam is the standardized chemistry entrance assessment used in Armenia for applicants to university chemistry, pharmacy, medicine, biology and related science programs. It is intended for secondary-school graduates and other candidates who need a formal chemistry score for admission, and it assumes a completed school course in general, inorganic and organic chemistry. The exam samples broadly across the discipline: atomic structure and periodicity, bonding and the structure of matter, main-group and transition-metal chemistry including coordination compounds, the mole concept and stoichiometry, kinetics, thermodynamics and equilibrium, solutions and acid-base chemistry, electrochemistry and redox, organic functional groups and reaction types, and basic laboratory safety and calculation. Tasks range from selected-response items to short constructed answers and longer multi-step problems, so both recall and structured working are rewarded. The Armenia Chemistry Unified Exam case studies are 5 cases and about 3,291 words.
1Identifying an Unknown Period 3 Chloride from Reactivity Data
A sealed 250 mL flask contains 0.0200 mol of a chloride of a Period 3 element, formula EClₙ (n = 1–4). The flask also holds 0.0600 mol of dry O₂.
974 words, about 5 min2Choosing an Indicator and Predicting the Endpoint for a Weak Acid Titration
A student must determine the concentration of a 25.0 mL sample of ethanoic acid (Ka = 1.8 × 10⁻⁵) using 0.100 mol/L NaOH. The available indicators are methyl orange (pH 3.1–4.4), bromothymol blue (pH 6.0–7.6) and phenolphthalein (pH 8.2–10.0).
539 words, about 3 min3Diagnosing a Galvanic Cell That Reads the Wrong Voltage
A student builds a cell: Zn(s) Zn²⁺(1.0 mol/L) Cu²⁺(1.0 mol/L) Cu(s) at 298 K, using a KNO₃ salt bridge and a high-impedance voltmeter. Standard potentials: E°(Zn²⁺/Zn) = −0.76 V; E°(Cu²⁺/Cu) = +0.34 V.
555 words, about 3 min4Deciding Whether a Reaction Will Precipitate or Dissolve: Competing Equilibria
A 100 mL sample of industrial wastewater contains Mg²⁺ at 0.010 mol/L and Ca²⁺ at 0.0050 mol/L. The plant adds NaOH to raise the pH to precipitate the metals as hydroxides.
539 words, about 3 min5Distinguishing Two Isomers of C₄H₈O by Chemical Tests
Two colourless liquids, A and B, both have molecular formula C₄H₈O (M = 72 g/mol). Both are neutral to litmus.
684 words, about 3 min