SASS Chem Haber Process

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY 18.1 The Haber Process AMMONIA Assessment for Learning 1 The equation shows the reaction for the manufacture of ammonia. N2 (g) + 3 H2 (g)⇌ 2 NH3 (g) Which change will not increase the yield of this reaction? A Addition of Fe catalyst B Decrease in temperature C Increase in molar volumes of each reactant D Increase in pressure 2 In the Haber process, nitrogen and hydrogen react to form ammonia. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ∆H = –92 kJ Which factor increases both the speed of reaction and the amount of ammonia formed? A Addition of Fe catalyst B Decrease in temperature C Increase in pressure D Increase in temperature 3 The diagram shows the main stages in the manufacture of ammonia. Which of the following best describes the process labelled X? A Ammonia is returned to the start of the process to form a larger amount of the product. B The gases are cooled to cause ammonia to form a liquid. C Unreacted hydrogen only is recycled. D Unreacted hydrogen and nitrogen are recycled. [Turn Over CHEMISTRY (G3) 6092 MARKING SCHEME Section A [5 Marks] 1 2 3 4 5 D B B D C Section B Qn Answers Mark Remarks 6 (a)(i) A and H [1] 6 (a)(ii) B [1] 6 (a)(iii) D [1] 6 (a)(iv) C and E or C and G [1] 6 (b) F F contains 10 electrons arranged in 3 electron shells, with its 2nd electron shell incompletely filled with only 6 electrons. [1] [1] Accept any plausible answers. 6 (c)(i) H– [1] Rej. chemical name / G–. 6 (c)(ii) Aluminium [1] 7 (a) X : Liquid Y : Liquid and Solid Z : Solid [1] deducted for each mistake [2] Rej. additional state(s) provided for each stage. 7 (b)(i) 113.7 [1] 7 (b)(ii) Heat energy is released to the surroundings (during freezing) as the particles are attracted to each other to form a solid. [1] 8 (a) –69 ℃ [1] 8 (b)(i) MgCl2 SCl2 [4] MgCl2 [1] stoichiometry and charge on both ions. [1] octet structure. SCl2 [1] no. of electrons shared. [1] no. of non-bonding / lone pair of electrons. ✓╳╳ Mg╳╳╳╳╳╳ 2+Cl−●●●●●●●╳2 ●╳SCl╳╳ ╳╳╳╳ Cl╳╳ ╳╳╳╳●╳●●●● ST ANDREW’S SECONDARY SCHOOL WEIGHTED ASSESSMENT 2 2022 SECONDARY 3 8 © UCLES 2018 5070/11/O/N/18 20 T h r e e s e p a r a t e m i x t u r e s o f a s o l u t i o n a n d a s o l i d a r e m a d e , a s s h o w n i n t h e t a b l e . The mixtures are warmed. In which mixtures does gas form? NaOH(aq) and NH4Cl (s) H2SO4(aq) and NH4Cl (s) H2SO4(aq) and Mg(s) A key B = gas forms C = no gas forms D 21 I n s o l u b l e s a l t s a r e p r e p a r e d b y r e a c t i n g a q u e o u s s o l u t i o n s o f s o l u b l e s a l t s . A p r e c i p i t a t e f o r m s . Which pairs of aqueous solutions form a precipitate? 1 barium chloride and nitric acid 2 barium chloride and sulfuric acid 3 barium nitrate and nitric acid 4 barium nitrate and sulfuric acid A 1 a n d 2 B 1 a n d 3 C 2 a n d 4 D 3 a n d 4 22 The diagram shows the main stages in the manufacture of an ammonia-based fertiliser. N2(g) H2(g) iron 500 °C 200 atm pressure separation fertiliser manufacture X What is happening in the process labelled X? A A m m o n i a i s r e t u r n e d t o t h e s t a r t o f t h e p r o c e s s t o s h i f t t h e e q u i l i b r i u m t o w a r d s t h e p r o d u c t . B T h e g a s e s a r e c o o l e d t o c a u s e a m m o n i a t o f o r m a l i q u i d . C U n r e a c t e d h y d r o g e n o n l y i s r e c y c l e d . D U n r e a c t e d h y d r o g e n a n d n i t r o g e n a r e r e c y c l e d .

Page 2 4 How is the reaction between nitrogen and hydrogen be described as? A A neutralisation reaction B A reduction reaction C A reversible reaction D An oxidation reaction 5 Which statement is not correct about the Haber process? A An iron catalyst is used. B Each nitrogen molecule reacts with three hydrogen atoms to form a molecule of ammonia. C Hydrogen for the process can be obtained by the cracking of oil. D The reaction is reversible. 6 Hydrogen and nitrogen react to form ammonia. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) Which statement is correct? A Ammonia is made in industry by the Contact process. B Ammonia is used in the industry to make hydrogen and nitrogen. C Hydrogen, for the forward reaction, is obtained from cracking of oil. D Weed killers are manufactured from ammonia. 7 Ammonia is manufactured by the Haber process. N2 (g) + 3 H2 (g) ⇌ 2 NH3 (g) ∆H = –92 kJ For this reaction, which rows give a true statement together with a correct reason? Statement Reason 1 Nitrogen and hydrogen are mixed in the ratio 1:3 by volume. The formula of ammonia is NH3. 2 The pressure used is approximately 200 atm. A high pressure is needed to produce a good yield of ammonia at equilibrium. 3 The temperature used is approximately 450 ℃. A high temperature is needed to produce a good yield of ammonia at equilibrium. 4 Vanadium(V) oxide is used as the catalyst. A catalyst speeds up the rate of the reaction. A 1, 2 and 3 only B 1 and 2 only C 2 and 3 only D 3 and 4 only

Page 3 Use the information provided below to answer questions 8 – 10. The Haber process is used to produce ammonia from hydrogen and nitrogen on an industrial scale. The diagram shows an illustration of this process. 8 What is the purpose of the heat exchanger? A To cool the incoming gas mixture to avoid overheating the catalyst. B To cool the incoming gas mixture to produce more ammonia. C To cool the reaction products and separate the ammonia from unused reactants. D To warm the incoming gas mixture to produce more ammonia. 9 Which substance is most suitable for use in the catalytic converter? A 1 g of granular iron B 1 g of powdered iron C 1 g of powdered nickel D 1 g of powdered vanadium 10 Which statement is not correct about this process? A Ammonia has a higher boiling point than hydrogen or nitrogen. B Ammonia has a lower boiling point than hydrogen or nitrogen. C Ammonia is collected in its liquid state. D The yield of this process never reaches 100 %. Nitrogen Hydrogen NH3 Condenser Heat Exchanger CatalyticConverter