ACSBR 3 Chemical Equations - Assignment ANS

Anglo-Chinese School (Barker Road) A Methodist Institution Founded in 1886 CHEMISTRY DEPARTMENT OF SCIENCE Name: ANSWERS ( ) Class: SEC 3 CHEMICAL FORMULAE & EQUATIONS – ASSIGNMENT ALEX LEE/2010 PAGE 1 OF 4 PURE/COMBINED/N-LEVEL Multiple-Choice Questions [20 Marks] TOTAL SCORE / 30 Write in your selected answer for the multiple-choice questions in the boxes provided. 1 2 3 4 5 6 7 8 9 10 D C B B D C B A A A 11 12 13 14 15 16 17 18 19 20 A C B A C C C C D D 1. Which of the following ions is not a molecular ion? A ammonium ion B hydroxide ion C nitrate ion D sulfide ion 2. Which of the following substances contains both covalent and ionic bonds? A Al2O3 B C6H12O6 C NH4NO3 D SiO2 3. In which of the following sets do all the compounds contain only ionic bonds? A calcium oxide; carbon dioxide; magnesium oxide B calcium oxide; magnesium oxide; sodium chloride C carbon dioxide; copper(II) sulfate; hydrogen chloride D copper(II) sulfate; hydrogen chloride; magnesium oxide 4. What is the chemical formula for barium hydroxide? A BaOH B Ba(OH)2 C BaOH2 D (Ba)OH3 5. What is the chemical formula for copper(II) nitrate? A CuNO3 B Cu2NO3 C Cu3NO2 D Cu(NO3)2 6. What is the formula for diphosphorus pentaoxide? A PO4 B PO5 C P2O5 D P3O4

ALEX LEE/2010 PAGE 2 OF 4 7. What are the formulae for ammonia, carbon dioxide and methane? ammonia carbon dioxide methane A AH CO2 MH4 B NH3 CO2 CH4 C NH4 C2O2 MH4 D A2H CO2 CH4 8. An unknown element X forms an ionic compound of the formula X2SO4. What is the formula for the ion of X? A X+ B X2+ C X3+ D X4+ 9. An unknown element Y forms a compound Al2Y3 with aluminium. What is the formula of the compound formed between Y and magnesium? A MgY B MgY2 C MgY3 D Mg2Y3 10. What is the chemical formula for diamond and graphite? diamond graphite A C C B C C60 C C4 C D C4 C60 11. A portion of an ionic lattice is shown below. Legend: element Q element R What is the formula of this compound? A QR B Q2R C QR4 D Q13R14 12. What is the number of electrons present in a carbonate ion? A 28 B 30 C 32 D 36 13. Seven gaseous elements are listed below. argon chlorine fluorine helium hydrogen nitrogen oxygen How many of the above elements occur naturally as diatomic molecules? A 4 B 5 C 6 D 7

ALEX LEE/2010 PAGE 3 OF 4 14. Several elements and their formulae are shown below. Which formula is incorrect? A bromine, Br B iodine, I2 C krypton, Kr D nitrogen, N2 15. Several elements and their formulae are shown below. Which formula is incorrect? A argon, Ar B hydrogen, H2 C magnesium, Mg2 D sodium, Na 16. A chemical equation is shown below: a NH3 + b CH4 + c O2 ⎯→ d HCN + e H2O Given that a, b, c, d and e are the smallest possible integer values for the equation to be balanced, what is the value of e? A 2 B 4 C 6 D 7 17. A chemical equation is shown below: a CH3(CH2)3COOH + b O2 ⎯→ c CO2 + d H2O Given that a, b, c and d are the smallest possible integer values for the equation to be balanced, what is the value of b? A 6 B 7 C 13 D 15 18. Some iron fillings were burnt in the presence of oxygen, forming iron(III) oxide. Which of the following equations correctly represents this reaction? A 2 Fe + 3 O ⎯→ Fe2O3 B 3 Fe + O2 ⎯→ Fe3O2 C 4 Fe + 3 O2 ⎯→ 2 Fe2O3 D Fe2 + O3 ⎯→ Fe2O3 19. When solutions of barium chloride and lead(II) nitrate are mixed, a white precipitate of lead(II) chloride is formed, leaving a solution of barium nitrate as the byproduct. Which of the following equations correctly represents this reaction? A BaCl2 (l) + 2 Pb(NO3)2 (l) ⎯→ 2 PbCl2 (s) + Ba(NO3)2 (l) B BaCl2 (aq) + PbNO3 (s) ⎯→ BaNO3 (s) + PbCl2 (s) C Pb(NO3)2 (aq) + 2 BaCl2 (aq) ⎯→ 2 PbCl2 (s) + Ba(NO3)2 (aq) D Pb(NO3)2 (aq) + BaCl2 (aq) ⎯→ Ba(NO3)2 (aq) + PbCl2 (s) 20. Which of the following equations best represents water boiling? A 2 H2O (l) ⎯→ 2 H2 (g) + O2 (g) B H2O (aq) ⎯→ 2 H (g) + O (g) C H2O (aq) ⎯→ H2O (g) D H2O (l) ⎯→ H2O (g)

ALEX LEE/2010 PAGE 4 OF 4 Structured Questions [10 Marks] 21. Construct balanced chemical equations, including state symbols, for the chemical reactions as described below. [10] (a) Aluminium combines directly with chlorine to form aluminium chloride. 2 Al (s) + 3 Cl2 (g) ⎯→ 2 AlCl3 (s) (b) Zinc metal reacts with dilute nitric acid to form aqueous zinc nitrate and hydrogen. Zn (s) + 2 HNO3 (aq) ⎯→ Zn(NO3)2 (aq) + H2 (g) (c) Ammonia reacts oxygen to form nitrogen monoxide and water vapour. 4 NH3 (g) + 5 O2 (g) ⎯→ 4 NO (g) + 6 H2O (g) (d) Hydrogen is produced when methane is reformed with steam. Carbon monoxide is a byproduct of this industrial process. CH4 (g) + H2O (g) ⎯→ 3 H2 (g) + CO (g) (e) Iron reacts with dilute silver nitrate, forming aqueous iron(II) nitrate and silver. Fe (s) + 2 AgNO3 (aq) ⎯→ Fe(NO3)2 (aq) + 2 Ag (s) END