documents related to econ and english, Ispiti od Termodinamica Chimica

Preuzmite documents related to econ and english i više Ispiti u PDF od Termodinamica Chimica samo na Docsity! Paper 1 Energetics SL exam [20 marks] 1. [1 mark] Which equation represents the N–H bond enthalpy in NH3? A. NH3 (g) → N (g) + 3H (g) B. ! " NH3 (g) → !"N (g) + H (g) C. NH3 (g) → !#N2 (g) + " # H2 (g) D. NH3 (g) → •NH2 (g) + •H (g) 2. [1 mark] Questions 2 and 3 are about an experiment to measure the enthalpy of combustion, ΔHc, of ethanol, using the apparatus and setup shown. Which quantity is likely to be the most inaccurate due to the sources of error in this experiment? A. Mass of ethanol burnt B. Molecular mass of ethanol C. Mass of water D. Temperature change 3. [1 mark] What is the enthalpy of combustion, ΔHc, of ethanol in kJ mol−1? Maximum temperature of water: 30.0°C Initial temperature of water: 20.0°C Mass of water in beaker: 100.0 g Loss in mass of ethanol: 0.230 g Mr (ethanol): 46.08 Specific heat capacity of water: 4.18 J g−1 K−1 q = mcΔT A. − !$$.$×'.!(×(!$.$×#*")!.#$! %&.!'×!$$$ B. − $.$#"$×'.!(×!$.$(!!.! %&.!'×!$$$ C. − !$$.$×'.!(×!$.$!.#$! %&.!'×!$$$ D. − !$$.$×'.!(×!$.$!.#$! %&.!' 8. [1 mark] What is the enthalpy change of reaction for the following equation? A. x + y + z B. −x − y + z C. x − y − z D. x − y + z 9. [1 mark] When equal masses of X and Y absorb the same amount of energy, their temperatures rise by 5 °C and 10 °C respectively. Which is correct? A. The specific heat capacity of X is twice that of Y. B. The specific heat capacity of X is half that of Y. C. The specific heat capacity of X is one fifth that of Y. D. The specific heat capacity of X is the same as Y. 10. [1 mark] Consider the following reaction: N2 (g) + 3H2 (g) ⇌ 2NH3 (g) Which calculation gives ΔHΘ, in kJ, for the forward reaction? A. 2z − y − 3x B. y + 3x − 2z C. y + 3x − 6z D. 6z − y − 3x 11. [1 mark] Consider the following reactions: Fe2O3 (s) + CO (g) → 2FeO (s) + CO2 (g) ΔHΘ = −3 kJ Fe (s) + CO2 (g) → FeO (s) + CO (g) ΔHΘ = +11 kJ What is the ΔHΘ value, in kJ, for the following reaction? Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g) A. −25 B. −14 C. +8 D. +19 12. [1 mark] Two 100 cm3 aqueous solutions, one containing 0.010 mol NaOH and the other 0.010 mol HCl, are at the same temperature. When the two solutions are mixed the temperature rises by y °C. Assume the density of the final solution is 1.00 g cm−3. Specific heat capacity of water = 4.18 J g−1 K−1 What is the enthalpy change of neutralization in kJ mol−1? A. #$$×'.!(×, !$$$×$.$#$ B. #$$×'.!(×, !$$$×$.$!$ C. !$$×'.!(×, !$$$×$.$!$ D. #$$×'.!(×(,-#*") !$$$×$.$!$ 13. [1 mark] What is the enthalpy change of combustion of urea, (NH2)2CO, in kJ mol−1? 2(NH2)2CO(s) + 3O2(g) → 2CO2(g) + 2N2(g) + 4H2O(l) A. 2 × (−333) −2 × (−394) −4 × (−286) B. ! # [2 × (−394) + 4 × (−286) −2 × (−333)] C. 2 × (−394) + 4 × (−286) −2 × (−333) D. ! # [2 × (−333) −2 × (−394) −4 × (−286)]