Topics in the June 2010 Exam Paper for CHEM1001

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1 June 2010 Topics in the June 2010 Exam Paper for CHEM1001 Click on the links for resources on each topic J-2: 2010-J-3: 2010-J-4: 2010-J-5: 2010-J-6: 2010-J-7: 2010-J-8: 2010-J-9: 2010-J-10: 2010-J-11: 2010-J-12: 2010-J-13: Molecules and Ions Stoichiometry Lewis Model of Bonding VSEPR The Periodic Table Atomic Energy Levels Stoichiometry Gas Laws Stoichiometry Gas Laws Chemical Equilibrium Thermochemistry First Law of Thermodynamics Chemical Equilibrium Equilibrium and Thermochemistry in Industrial Processes Electrochemistry Electrolytic Cells Electrochemistry Types of Intermolecular Forces Batteries and Corrosion

2 2201(a) THE UNIVERSITY OF SYDNEY FUNDAMENTALS OF CHEMISTRY 1A - CHEM1001 FIRST SEMESTER EXAMINATION CONFIDENTIAL JUNE 2010 TIME ALLOWED: THREE HOURS GIVE THE FOLLOWING INFORMATION IN BLOCK LETTERS FAMILY NAME OTHER NAMES SID NUMBER TABLE NUMBER INSTRUCTIONS TO CANDIDATES All questions are to be attempted. There are 22 pages of examinable material. Complete the written section of the examination paper in INK. Read each question carefully. Report the appropriate answer and show all relevant working in the space provided. The total score for this paper is 100. The possible score per page is shown in the adjacent tables. Each new short answer question begins with a. Only non-programmable, Universityapproved calculators may be used. Students are warned that credit may not be given, even for a correct answer, where there is insufficient evidence of the working required to obtain the solution. Numerical values required for any question, standard electrode reduction potentials, a Periodic Table and some useful formulas may be found on the separate data sheets. Page 24 is for rough working only. OFFICIAL USE ONLY Multiple choice section Pages Max Gained Short answer section Page Max Gained Marker Total 66 Check Total

3 CHEM J (a) Complete the following table. phosphorus trichloride Name Formula NH 3 2 calcium phosphate KHCO 3 Calculate the number of aluminium atoms in a block of pure aluminium that measures 2.0 cm 2.0 cm 3.0 cm. The density of aluminium is 2.7 g cm 3. 2 THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY

4 CHEM J (a) Complete the following table. 6 Molecule NH 3 SF 4 CO 2 Number of bonding electron pairs Number of nonbonding electron pairs on central atom Lewis structure Molecular shape What is resonance? Illustrate your answer by using the nitrate ion, NO 3, as an example. 3

5 CHEM J (a) The element titanium is used as a structural material for bone in joint replacement surgery. Discuss the properties of titanium that make it suitable for this application. 3 Gaseous lithium atoms absorb light with a wavelength of 323 nm. The resulting excited lithium atoms lose some energy through collisions with other atoms. One of the emission lines has an energy of J. Calculate the energy of the light used for the excitation. 4 Calculate the wavelength of the light emitted.

6 CHEM J (a) Lead ions react with bromide ions according to the following equation. Pb 2+ (aq) + 2Br (aq) PbBr 2 (s) If M lead(ii) nitrate solution (100.0 ml) is added to M potassium bromide solution (300.0 ml), what amount (in mol) of lead(ii) bromide precipitates? 4 What is the final concentration of NO 3 (aq) ions remaining in solution after the reaction?

7 CHEM J (a) Respiration involves the oxidation of glucose to produce carbon dioxide, water and energy: C 6 H 12 O 6 (s) + O 2 (g) CO 2 (g) + H 2 O(l) Balance this equation. 4 What volume of CO 2 (g) is produced from the oxidation of 10.0 g of glucose under body conditions (37 C, Pa)? THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY

8 CHEM J (a) An unknown liquid contains H: 5.90 % and O: 94.1 % by mass and has a molar mass of 33.9 g mol 1. What is its molecular formula? 2 A 2.4 g sample of zinc was dropped into L of 5.0 M HCl in a 5.00 L container at 25 C with an initial pressure of 1.0 atm and then the vessel sealed. Calculate the final pressure inside the container. Hint: The volume occupied by the HCl is significant. 6

9 CHEM J (a) Consider the following equilibrium reaction. 4HCl(g) + O 2 (g) 2H 2 O(g) + 2Cl 2 (g) K c = 885 at 500 o C If mol HCl, mol O 2, mol H 2 O and mol Cl 2 are mixed in a 1.0 L container at 500 o C, in what direction will the reaction proceed? 3 What is the value of K p for the reaction at 500 o C? THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY

10 CHEM J (a) How much energy is needed to convert 15 g of ice at 0.0 C to water at 60.0 C? The molar heat of fusion of water is kj mol 1 and the specific heat capacity of water is 4.18 J g 1 K 1. 3 Calculate the standard enthalpy change for the combustion of 1.00 mol of propane gas, C 3 H 8 (g), to CO 2 (g) and H 2 O(l). 3 compound C 3 H 8 (g) CO 2 (g) H 2 O(l) Δ f H / kj mol

11 CHEM J (a) Ammonia can be produced according to the following equation. N 2 (g) + 3H 2 (g) 2NH 3 (g) H = 92.4 kj mol 1 6 K c = at 500 K. What is the concentration of ammonia at equilibrium if 0.5 mol of N 2 (g) and 1.5 mol of H 2 (g) are placed in an empty 2.0 L flask and allowed to come to equilibrium at 500 K? An additional 0.5 mol of nitrogen is added to the flask described above and equilibrium re-established. Will the equilibrium constant have increased, decreased or remained the same? Justify your answer. What now is the equilibrium concentration of ammonia?

12 CHEM J (a) Write the two half equations and hence balance the equation for the following redox reaction: 3 Working MnO 2 + NaCl + H 2 SO 4 MnSO 4 + H 2 O + Cl 2 + Na 2 SO 4 Balanced equation: Which species is oxidised? In the electro-refining of Pt, what mass of Pt is deposited from a solution of PtCl 6 2 in 1.00 hour, by a current of 1.62 A? 2

13 CHEM J (a) What is the voltage of the following electrochemical cell at 25 C? Zn(s) Zn 2+ (aq)( M) Cu 2+ (aq)(0.100 M) Cu(s) 3 Rationalise the order of the boiling points of the following liquids in terms of their intermolecular forces. 3 liquid F 2 HCl HBr Cl 2 HF Br 2 b.p. ( C)

14 CHEM J (a) The aluminium-air battery, in which aluminium metal is oxidised to Al 3+ and O 2 is reduced to OH, is being considered as a power source in cars. Briefly compare the relative merits of such a battery with those of a fuel cell for such applications. 4 THE REMAINDER OF THIS PAGE IS FOR ROUGH WORKING ONLY

15 2201(b) June 2010 CHEM1001 FUNDAMENTALS OF CHEMISTRY 1A DATA SHEET Physical constants Avogadro constant, N A = mol 1 Faraday constant, F = C mol 1 Planck constant, h = J s Speed of light in vacuum, c = m s 1 Rydberg constant, E R = J Boltzmann constant, k B = J K 1 Permittivity of a vacuum, 0 = C 2 J 1 m 1 Gas constant, R = J K 1 mol 1 = L atm K 1 mol 1 Charge of electron, e = C Mass of electron, m e = kg Mass of proton, m p = kg Mass of neutron, m n = kg Properties of matter Volume of 1 mole of ideal gas at 1 atm and 25 C = 24.5 L Volume of 1 mole of ideal gas at 1 atm and 0 C = 22.4 L Density of water at 298 K = g cm 3 Conversion factors 1 atm = 760 mmhg = kpa 1 Ci = Bq 0 C = 273 K 1 Hz = 1 s 1 1 L = 10 3 m 3 1 tonne = 10 3 kg 1 Å = m 1 W = 1 J s 1 1 ev = J Decimal fractions Decimal multiples Fraction Prefix Symbol Multiple Prefix Symbol 10 3 milli m 10 3 kilo k 10 6 micro 10 6 mega M 10 9 nano n 10 9 giga G pico p

16 2201(b) June 2010 CHEM1001 FUNDAMENTALS OF CHEMISTRY 1A Standard Reduction Potentials, E Reaction E / V Co 3+ (aq) + e Co 2+ (aq) Ce 4+ (aq) + e Ce 3+ (aq) MnO 4 (aq) + 8H + (aq) + 5e Mn 2+ (aq) + 4H 2 O Au 3+ (aq) + 3e Au(s) Cl 2 + 2e 2Cl (aq) O 2 + 4H + (aq) + 4e 2H 2 O Pt 2+ (aq) + 2e Pt(s) MnO 2 (s) + 4H + (aq) + e Mn H 2 O NO 3 (aq) + 4H + (aq) + 3e NO(g) + 2H 2 O Pd 2+ (aq) + 2e Pd(s) Ag + (aq) + e Ag(s) Fe 3+ (aq) + e Fe 2+ (aq) Cu + (aq) + e Cu(s) Cu 2+ (aq) + 2e Cu(s) Sn 4+ (aq) + 2e Sn 2+ (aq) H + (aq) + 2e H 2 (g) 0 (by definition) Fe 3+ (aq) + 3e Fe(s) 0.04 Pb 2+ (aq) + 2e Pb(s) 0.13 Sn 2+ (aq) + 2e Sn(s) 0.14 Ni 2+ (aq) + 2e Ni(s) 0.24 Cd 2+ (aq) + 2e Cd(s) 0.40 Fe 2+ (aq) + 2e Fe(s) 0.44 Cr 3+ (aq) + 3e Cr(s) 0.74 Zn 2+ (aq) + 2e Zn(s) H 2 O + 2e H 2 (g) + 2OH (aq) 0.83 Cr 2+ (aq) + 2e Cr(s) 0.89 Al 3+ (aq) + 3e Al(s) 1.68 Mg 2+ (aq) + 2e Mg(s) 2.36 Na + (aq) + e Na(s) 2.71 Ca 2+ (aq) + 2e Ca(s) 2.87 Li + (aq) + e Li(s) 3.04

17 2201(b) June 2010 CHEM1001 FUNDAMENTALS OF CHEMISTRY 1A Useful formulas Quantum Chemistry E = h = hc/ = h/mv E = Z 2 E R (1/n 2 ) x (mv) h/4 q = 4 r T 4 T = K nm Acids and Bases pk w = ph + poh = pk w = pk a + pk b = ph = pk a + log{[a ] / [HA]} Radioactivity t ½ = ln2/ A = N ln(n 0 /N t ) = t 14 C age = 8033 ln(a 0 /A t ) years Colligative Properties & Solutions = crt P solution = X solvent P solvent c = kp T f = K f m T b = K b m Miscellaneous I A = log I A = cl 0 2 e E = A 4 r 0 N A Electrochemistry G = nfe Moles of e = It/F E = E (RT/nF) logq = E (RT/nF) lnq E = (RT/nF) logk = (RT/nF) lnk E = E logq (at 25 C) n Gas Laws PV = nrt (P + n 2 a/v 2 )(V nb) = nrt E k = ½mv 2 Kinetics t ½ = ln2/k k = Ae Ea/RT ln[a] = ln[a] 0 kt k 2 Ea ln = k R T T ( ) Thermodynamics & Equilibrium G = H T S G = G + RT lnq G = RT lnk univ S = R lnk K p = K c (RT) n Mathematics If ax 2 + bx + c = 0, then x = ln x = log x Area of circle = r 2 Surface area of sphere = 4 r 2 2a 2 b b 4ac

18 PERIODIC TABLE OF THE ELEMENTS HYDROGEN H HELIUM He LITHIUM Li BERYLLIUM Be BORON B CARBON C NITROGEN N OXYGEN O FLUORINE F NEON Ne SODIUM Na MAGNESIUM Mg ALUMINIUM Al SILICON Si PHOSPHORUS P SULFUR S CHLORINE Cl ARGON Ar POTASSIUM K CALCIUM Ca SCANDIUM Sc TITANIUM Ti VANADIUM V CHROMIUM Cr MANGANESE Mn IRON Fe COBALT Co NICKEL Ni COPPER Cu ZINC Zn GALLIUM Ga GERMANIUM Ge ARSENIC As SELENIUM Se BROMINE Br KRYPTON Kr RUBIDIUM Rb STRONTIUM Sr YTTRIUM Y ZIRCONIUM Zr NIOBIUM Nb MOLYBDENUM Mo TECHNETIUM Tc [98.91] 44 RUTHENIUM Ru RHODIUM Rh PALLADIUM Pd SILVER Ag CADMIUM Cd INDIUM In TIN Sn ANTIMONY Sb TELLURIUM Te IODINE I XENON Xe CAESIUM Cs BARIUM Ba HAFNIUM Hf TANTALUM Ta TUNGSTEN W RHENIUM Re OSMIUM Os IRIDIUM Ir PLATINUM Pt GOLD Au MERCURY Hg THALLIUM Tl LEAD Pb BISMUTH Bi POLONIUM Po [210.0] 85 ASTATINE At [210.0] 86 RADON Rn [222.0] 87 FRANCIUM Fr [223.0] 88 RADIUM Ra [226.0] RUTHERFORDIUM Rf [261] 105 DUBNIUM Db [262] 106 SEABORGIUM Sg [266] 107 BOHRIUM Bh [262] 108 HASSIUM Hs [265] 109 MEITNERIUM Mt [266] 110 DARMSTADTIUM Ds [271] 111 ROENTGENIUM Rg [272] 112 COPERNICIUM Cn [283] LANTHANOID S 57 LANTHANUM La CERIUM Ce PRASEODYMIUM Pr NEODYMIUM Nd PROMETHIUM Pm [144.9] 62 SAMARIUM Sm EUROPIUM Eu GADOLINIUM Gd TERBIUM Tb DYSPROSIUM Dy HOLMIUM Ho ERBIUM Er THULIUM Tm YTTERBIUM Yb LUTETIUM Lu ACTINOIDS 89 ACTINIUM Ac [227.0] 90 THORIUM Th PROTACTINIUM Pa [231.0] 92 URANIUM U NEPTUNIUM Np [237.0] 94 PLUTONIUM Pu [239.1] 95 AMERICIUM Am [243.1] 96 CURIUM Cm [247.1] 97 BERKELLIUM Bk [247.1] 98 CALIFORNIUM Cf [252.1] 99 EINSTEINIUM Es [252.1] 100 FERMIUM Fm [257.1] 101 MENDELEVIUM Md [256.1] 102 NOBELIUM No [259.1] 103 LAWRENCIUM Lr [260.1] 2201(b) CHEM1001 FUNDAMENTALS OF CHEMISTRY 1A June 2010