CAPE Chemistry Unit 1 case studies
CAPE Chemistry Unit 1 · Put your knowledge to work in context.
The Caribbean Advanced Proficiency Examination (CAPE®) is a post-secondary qualification administered by the Caribbean Examinations Council (CXC®), the regional body whose headquarters are at Prince Road, Pine Plantation Road, St. Michael BB11091, Barbados, with a Western Zone Office at Caenwood Centre, 37 Arnold Road, Kingston 5, Jamaica. The CAPE Chemistry Unit 1 case studies are 5 cases and about 3,668 words.
1Four unlabelled solids and a colleague with two rules
A school laboratory is clearing out a store cupboard and finds four unlabelled white solids, W, X, Y and Z. The technician records the data below.
796 words, about 4 min2Copper(II) sulfate preparation: who is limiting, and where did the yield go?
An upper-sixth student prepares hydrated copper(II) sulfate from copper(II) oxide and dilute sulfuric acid. The student weighs 2.00 g of copper(II) oxide (Mr = 79.5) into a beaker, adds 25.0 cm3 of 1.50 mol dm-3 sulfuric acid, warms the mixture and stirs.
721 words, about 4 min3Successive ionisation energies: deciding between carbon, silicon and a metal
A student is given the successive ionisation energies of an unknown Period 3 element X, in kJ mol-1: 786, 1577, 3232, 4356, 16 091, 19 805, 23 780, 29 287, 33 878, 38 726, 45 962, 50 502, 235 196, 257 923. The student is also told that X forms a dioxide, XO2, which is a hard solid melting above 1700 °C and is insoluble in water, and a tetrachloride, XCl4, which is a colourless fuming liquid (boiling point 58 °C) that is hydrolysed violently by water.
751 words, about 4 min4Which bromobutane is which: timing the silver nitrate test
Three colourless liquids, A, B and C, are known to be 1-bromobutane, 2-bromobutane and 2-bromo-2-methylpropane, but the labels have been lost. A student puts five drops of each into separate test tubes containing 5.0 cm3 of ethanol and 5.0 cm3 of 0.020 mol dm-3 silver nitrate solution, warms them together in a 60 °C water bath and times the first appearance of a pale yellow precipitate: A, 8 s; B, 95 s; C, 12 min.
679 words, about 3 min5Enthalpy of combustion of propan-1-ol: a spirit burner that gives 72 per cent
A student determines the enthalpy of combustion of propan-1-ol with a spirit burner. The burner is weighed before and after heating 200 g of water in a copper can: 186.42 g before, 185.17 g after.
721 words, about 4 min