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Methane, carbon dioxide and water vapour are all greenhouse gases. Which property do these gases share that makes them greenhouse gases? A. They absorb the ultraviolet part of solar radiation before it reaches the Earth's surface. B. They are all produced only…
The NMR spectra of four compounds are described below. Which is the spectrum of propanone, CH3COCH3? Use section 21 of the data booklet. A. one singlet at 2.2 ppm B. a quartet at 2.4 ppm and a triplet at 1.0 ppm, with relative areas 2 : 3…
The mass spectra of four compounds are shown below. Which is the spectrum of propanal, CH3CH2CHO? Use section 22 of the data booklet. A. spectrum A B. spectrum B C. spectrum C D. spectrum D
A student mixes a solution of citric acid with solid sodium hydrogencarbonate in an insulated polystyrene cup fitted with a thermometer. The energy profile of the reaction is shown. Which combination is correct? A. the temperature of the solution rises;…
Methanol can be synthesized from carbon monoxide and hydrogen: CO(g) + 2 H2(g) → CH3OH(l) What is the enthalpy change for the synthesis of liquid methanol, in kJ mol−1? A. +129 B. −53 C. −129 D. −1581
Which of these fuels comes from a renewable energy source? A. kerosene obtained from crude oil B. biodiesel produced from rapeseed oil C. lignite (brown coal) D. hydrogen produced from natural gas
Which processes in the Born–Haber cycle for magnesium oxide are endothermic? I. Enthalpy of formation of magnesium oxide, II. Second electron affinity of oxygen, O−(g) + e− → O2−(g) III. Lattice enthalpy of…
A reaction mixture is moving towards equilibrium, and the forward reaction is proceeding faster than the reverse reaction. Which statement is correct? A. Q > K and ΔG > 0 B. Q < K and ΔG < 0 C. Q decreases towards zero while K remains…
10.0 cm3 of a gaseous hydrocarbon, CxHy, is burned completely in exactly the required volume of oxygen. The gaseous products occupy 70.0 cm3. This falls to 30.0 cm3 once the water vapour present condenses, with…
In the energy profile of a reaction shown below, P, Q and R are energies measured from the same baseline. Which expressions give the activation energy of the forward reaction, Ea, and the enthalpy change of the forward reaction, ΔH? A. Ea = Q;…