SASS Chem Properties and Uses of Ammonia

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS DATE CHEMISTRY (G3) 6092 18.2 Properties and Uses of Ammonia AMMONIA Assessment for Learning 1 Two statements about the bubbling of ammonia in pure water are provided. Statement 1: pH of the pure water decreases. Statement 2: Ammonia increases alkalinity. Which is correct? A Both statements are correct and statement 2 explains statement 1. B Both statements are correct but statement 2 does not explain statement 1. C Statement 1 is correct but statement 2 is incorrect. D Statement 2 is correct but statement 1 is incorrect. 2 The diagram shows a bag of SUPERGROW fertiliser. Which combination of chemical compounds would produce the fertiliser? A Ca3(PO4)2, KCl and (NH4)2SO4 B CH3CO2K, CO(NH2)2 and Pb(NO3)2 C KH2PO4 and NH4NO3 D K2O and (NH4)3PO4 3 One mole of substance X forms three moles of ions in aqueous solution. Ammonium carbonate reacts with the aqueous solution of substance X to produce an acidic gas. Which compound could be substance X? A Ethanoic acid B Magnesium hydroxide C Sodium hydroxide D Sulfuric acid [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 10 © UCLES 2015 0439/13/M/J/15 29 W h i c h c o m b i n a t i o n o f c h e m i c a l c o m p o u n d s c o u l d b e u s e d t o p r o d u c e t h e f e r t i l i z e r s h o w n ? SUPERGROW N P K 21 16 8:: A (NH4)3PO4, KCl B NH4NO3, Ca3(PO4)2 C NH4NO3, CO(NH2)2 D NH4NO3, K2SO4, (NH4)2SO4 30 B e l o w a r e t w o s t a t e m e n t s a b o u t s u l f u r d i o x i d e . 1 Sulfur dioxide is formed when fossil fuels burn and it is an acidic oxide. 2 Sulfur dioxide is one of the gases in the air which is responsible for ‘acid rain’. Which is correct? A Both statements ar