Illinois JETS Academic Challenge Chemistry Test (District) Useful Information. PV = nrt R = L atm mol -1 K -1.

Transcription

1 Useful Information PV = nrt R = L atm mol -1 K -1 Q = m x T x s 1 atm = 760 torr Avogadro's number = x K = C ph = -log [H + ] 1 1 E = (-R H ) - n 2 n 2 f i R H = 2.18 x J/photon 1

2 1. The specific heat of lead is J/g C. If 74.0 J of heat is added to a 125 g piece of lead at 23.0 C, what is the final temperature of the lead? Assume that no heat is lost to the surroundings. a C b C c C d C e C 2. One industrial preparation of acetic acid occurs by the following reaction: CH 3 OH + CO CH 3 CO 2 H Estimate H for this reaction, using the following bond energies in kj/mol. C-C: 347 C-O: 358 C-H: 413 C=O: 799 O-H: 467 C O: 1072 a. +11 kj/mol b kj/mol c. -74 kj/mol d kj/mol e. none of the above 3. In an electrolytic cell, the cathode is the electrode a. where reduction occurs. b. toward which anions move. c. where electrons are removed from a reactant in solution. d. that releases cations into solution. e. none of the above 4. Which compound is a peroxide? a. Na 2 O 2 b. C 3 O 2 c. KO 2 d. H 2 O e. NO 2 5. In the reaction below mol of H 2 O 2 is consumed each second in 4 liters of solution. What is the rate of production of O 2? 2H 2 O 2 2H 2 O + O 2 a x 10-2 mol L -1 s -1 b x 10-3 mol L -1 s -1 c x 10-3 mol L -1 s -1 d x 10-3 mol L -1 s -1 e x 10-4 mol L -1 s Which of the following statements is false? a. H 2 SO 4 is a stronger acid than H 3 PO 4. b. HNO 3 is a stronger acid than HNO 2. c. HCl is a stronger acid than HBr. d. HCl is a stronger acid than H 2 S. e. HNO 2 is a stronger acid than H 2 O. 7. How many mols of ions are present in 100 ml of 0.20 M sodium carbonate? a mol b mol c mol d mol e mol 2

3 8. Which of the following observations is a chemical property? a. flammability b. melting point c. color d. density e. electrical conductivity 9. What is the mass in nanograms of one oxygen molecule? a. 1.9 x ng b. 3.2 x ng c. 3.2 x 10-8 ng d. 5.3 x ng e. 5.3 x ng 10. Which of the following salts is/areinsoluble in water? I. (NH 4 ) 3 (PO 4 ) 2 II. CaCl 2 III. MgCO 3 IV. CaSO 4 V. Fe(NO 3 ) 2 a. I only b. I and III c. III and IV d. II and IV e. all of them are insoluble 11. Vitamin C found in naturally in citrus fruit contains 40.92% C, 4.58% H, and 54.0% O by mass. What is its empirical formula? a. CHO b. CH 4 O c. HC 2 H 3 O 2 d. C 3 H 5 O 3 e. C 3 H 4 O 3 Use the choices below to answer the next two questions. Each choice represents 1 L of gas at STP. a. Cl 2 b. NH 3 c. CO 2 d. N 2 e. all the same 12. Which 1 L sample contains the greatest number of mols? 13. Molecules of which gas would have the greatest average kinetic energy? 14. A 2.0 L vessel is evacuated to a pressure of 1.3 x 10-9 atm. At 19 C, how many gas molecules are present in the flask? a. 9.2 x 10 9 b. 6.5 x c. 1.0 x d. 1.7 x 10-9 e. 1.1 x Which of the following electron configurations is correct? a. Ca [Ar]3d 2 b. I [Kr]5s 2 4d 10 4f 14 5p 5 c. Cu [Ar]4s 1 3d 10 d. Se -2 [Kr]5s 2 4d 10 5p 6 e. Fe +3 [Ar]4s 2 3d A new element has been discovered with properties similar to platinum. Z=110 for this this element. What is the most probable electron configuration for the element? a. [Xe]6s 2 4f 14 5d 8 b. [Xe]5d 10 c. [Rn]7s 2 5f 14 6d 8 d. [Rn]7s 2 6d 8 e. [Rn]6d 10 3

4 17. Which of the following choices has the largest bond angles? a. H-C-N in HCN b. H-C-H in CH 4 c. H-N-H in NH 3 d. F-B-F in BF 3 e. Cl-P-Cl in PCl Which of the following ions has a tetrahedral electron geometry and a pyramidal structure? a. -3 PO 4 b. -2 CO 3 c. - I 3 d. - ClO 3 e. + NH Draw the Lewis structure of SO 2 to help you determine which statement is true. a. SO 2 is a nonpolar molecule. b. The sulfur atom uses sp hybrid orbitals for bonding. c. The strongest intermolecular forces between SO 2 molecules are London dispersion forces. d. There is resonance delocalization of the pi electrons in SO 2. e. SO 2 has the same molecular structure as CO At 1495 K, K p is 2.86 x 10-5 for the reaction below: 2HBr(g) _ H 2 (g) + Br 2 (g) Calculate K p for the reaction: 4H 2 (g) + 4Br 2 (g) _ 8HBr(g) a. 187 b c x 10 4 d x e x Which of the following are conjugate acid/base pairs? I. H 2 O/OH - II. Hcl/Cl - III. HC 2 H 3 O 2 /OH - IV. NH + 4 /H + V. 2- H 2 SO 4 /SO 4 a. I and II b. II and V c. II, IV and V d. I, III and IV e. I, II and IV 22. What is the ph of a 2 x 10-9 M solution of HCl? a. 9.0 b. 5.0 c. 7.0 d. 8.7 e

5 23. Which choice lists the atoms in order of increasing ionization energy? Li, Na, C, O, F a. Li < Na < C < O < F b. Na < Li < C < O < F c. F < O < C < Li < Na d. Na < Li < F < O < C e. Na < Li < C < F < O 24. Which of the following contains only covalently bonded compounds? a. HCN, NO 2, Ca(NO 3 ) 2 b. PCl 5, LiBr, Zn(OH) 2 c. KOH, CCl 4, SF 4 d. NaH, CaF 2, NaNH 2 e. CH 2 O, H 2 S, NH What is the ionization energy of Cr 23+? a x 10 5 kj/mol b x kj/mol c x 10 5 kj/mol d x 10 4 kj/mol e x kj/mol 26. Which of the following is an isoelectronic series listed in order of increasing size? a. Hf 4+, La 3+, Ba 2+, Cs +, Xe b. S 2-, Cl -, Ar, K +, Ca 2+ c. La 2+, Ba 2+, Cs +, Xe, I - d. Sr 2+, Rb +, Kr, Br -, Se 2- e. Y 3+, Sr 2+, Kr, Rb +, Br If 4.0 mol of SO 3 and 3.0 mol of SO 2 are mixed in a 1.0 L container, the equilibrium concentration of O 2 is: 2SO 2 (g) + O 2 (g) _ 2SO 3 (g) K = 278 at 1000 K a mol/l b. 4.0 mol/l c mol/l d mol/l e mol/l 28. If an acid, HA, is 10.0% dissociated in a 1.0 M solution, what is the K a for this acid? a. 9.1 x 10-2 b. 1.1 x 10-2 c. 8.1 x 10-1 d. 6.3 x 10-2 e. none of these 29. Which of the following would make a buffer solution with the greatest buffer capacity? a M HF and 0.50M NaF b. 5.0 M HCl and 5.0 M NaCl c ml of 2.0 M HF and 50.0 ml of 1.0 M NaOH d. 4.0 M HF and 2.0 M HCl e. a. and c. have equivalent best buffer capacities. 30. What volume of a 12.0 M stock solution of HCl is required to make 500. ml of a M HCL solution? a ml b ml c ml d ml e. 480 ml 5

6 31. The density of Br 2 (g) at 600. torr and 100. C is: a g/l b g/l c g/l d g/l e g/l 32. The rate law for the reaction is Cl 2 + CHCl 3 CCl 4 + HCl Rate = k[cl 2 ] 1/2 [CHCl 3 ] What are the correct units of k? a. sec -1 b. Msec -1 c. M 2 sec -1 d. M -1/2 sec -1 e. M 1/2 sec The zinc in a g sample of foot powder was precipitated as ZnNH 4 PO 4. After the precipitate was heated, there remained g Zn 2 P 2 O 7. What is the mass percent of zinc in the original sample of foot powder? a % b % c % d % e % 34. When ml of M potassium chloride and ml of lead (II) nitrate are mixed, what mass of precipitate is formed? a g b g c g d g e g 35. How many grams of NH3 (MW = g/mol) has the same number of molecules as 15.0 g of C 6 H 6 (MW = g/mol)? a g b g c g d g e. none of the above 36. In the reaction below, what element is oxidized and what is reduced? 3CoSO 4 + 5KI + KIO 3 + 3H 2 O 3Co(OH) 2 + 3K 2 SO 4 + 3I 2 a. Co 2+ is oxidized, and the I in IO 3 - is reduced. b. I - is oxidized, and the I in IO 3 - is reduced. c. I in IO 3 - is oxidized and I - is reduced. d. I - is oxidized and Co 2+ is reduced. e. I in IO 3 - is oxidized and Co 2+ is reduced. 6

7 37. Which of the following would have the lowest boiling point? a. H 2 b. F 2 c. O 2 d. S 2 e. N The numbers of protons, neutrons and electrons in 138 Ba 2+ are: a. 69 p, 69 n, 67 e b. 56 p, 56 n, 54 e c. 56 p, 56 n, 56 e d. 56 p, 82 n, 54 e e. 56 p, 138 n, 82 e 39. Iron(II) sulfate reacts with potassium hydroxide in aqueous solution to form a precipitate. Which is the net ionic equation for this reaction? a. Fe 2+ (aq) + SO 2-4 (aq) FeSO 4 (s) b. 2K + (aq) + SO 2-4 (aq) K 2 SO 4 (s) c. 2Fe 3+ (aq) + 3SO 2-4 (aq) Fe 2 (SO 4 ) 3 (s) d. Fe 2+ (aq) + 2OH - (aq) Fe(OH) 2 (s) e. K + (aq) + Fe 2+ (aq) Fe 3+ (aq) 40. How many moles of NaF must beadded to 1.0 L of a M Ca(NO 3 ) 2 solution to begin precipitation of CaF 2 (s)? Assume that no volume change occurs.for CaF 2, K sp = 4.0 x a. Greater than 4.0 x b. Greater than 2.0 x 10-6 c. Greater than 6.3 x 10-7 d. Greater than 2.0 x 10-5 e. Greater than 4.0 x

8 1...D 2...A 3...A 4...A 5...D 6...C 7...E 8...A 9...D 10...C 11...E 12...E 13...E 14...B 15...C 16...C 17...A 18...D 19...D 20...D 21...A 22...C 23...B 24...E 25...A 26...D 27...E 28...B 29...E 30...A 31...E 32...D 33...D 34...B 35...A 36...B 37...A 38...C 39...A 40...D Correct Answers Distribution of Questions energy 1,2 electrochemistry 3, 36 elements and compounds 4 kinetics 5, 32 acids and bases 6, 21, 22, 28, 29 solutions 7, 10, 39, 40 stoichiometry 11, 33, 34, 35 gases 12, 13, 14, 31 atomic structure 15, 16, 25, 38 basic principles 8, 9, 30 molecular structures 17, 18, 19, 24 equilibrium 20, 27 periodic properties 23, 26 intermolecular forces 37 8