Science Olympiad Regional UW-Milwaukee Chemistry test 2013

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1 Science Olympiad Regional UW-Milwaukee Chemistry test 2013 Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. What is another name for the representative elements? a. Group A elements c. Group C elements b. Group B elements d. transition elements 2. Each period in the periodic table corresponds to. a. a principal energy level c. an orbital b. an energy sublevel d. a suborbital 3. Who arranged the elements according to atomic mass and used the arrangement to predict the properties of missing elements? a. Henry Moseley c. John Dalton b. Antoine Lavoisier d. Dmitri Mendeleev 4. Which of the following categories includes the majority of the elements? a. metalloids c. metals b. liquids d. nonmetals 5. What element has the electron configuration 1s 2s 2p 3s 3p? a. nitrogen c. silicon b. selenium d. silver 6. Which of the following is true about the electron configurations of the noble gases? a. The highest occupied s and p sublevels are completely filled. b. The highest occupied s and p sublevels are partially filled. c. The electrons with the highest energy are in a d sublevel. d. The electrons with the highest energy are in an f sublevel. 7. How does atomic radius change from top to bottom in a group in the periodic table? a. It tends to decrease. c. It first increases, then decreases. b. It tends to increase. d. It first decreases, then increases. 8. How does atomic radius change from left to right across a period in the periodic table? a. It tends to decrease. c. It first increases, then decreases. b. It tends to increase. d. It first decreases, then increases. 9. What causes the shielding effect to remain constant across a period? a. Electrons are added to the same principal energy level. b. Electrons are added to different principal energy levels. c. The charge on the nucleus is constant. d. The atomic radius increases. 10. What element in the second period has the largest atomic radius? a. carbon c. potassium b. lithium d. neon 11. Which of the following factors contributes to the increase in atomic size within a group in the periodic table as the atomic number increases? a. more shielding of the electrons by the highest occupied energy level b. an increase in size of the nucleus c. an increase in number of protons d. fewer electrons in the highest occupied energy level 12. Which of the following elements has the smallest atomic radius? a. sulfur c. selenium

2 b. chlorine d. bromine 13. The metals in Groups 1A, 2A, and 3A. a. gain electrons when they form ions c. all have ions with a 1 charge b. all form ions with a negative charge d. lose electrons when they form ions 14. Why is the second ionization energy greater than the first ionization energy? a. It is more difficult to remove a second electron from an atom. b. The size of atoms increases down a group. c. The size of anions decreases across a period. d. The nuclear attraction from protons in the nucleus decreases. 15. In which of the following sets are the charges given correctly for all the ions? a. Na, Mg, Al c. Rb, Ba, P b. K, Sr, O d. N, O, F 16. In which of the following groups of ions are the charges all shown correctly? a. Li, O, S c. K, F, Mg b. Ca, Al, Br d. Na, I, Rb 17. What is the element with the lowest electronegativity value? a. cesium c. calcium b. helium d. fluorine 18. What is the element with the highest electronegativity value? a. cesium c. calcium b. helium d. fluorine 19. Which of the following elements has the smallest ionic radius? a. Li c. O b. K d. S 20. What is the energy required to remove an electron from an atom in the gaseous state called? a. nuclear energy c. shielding energy b. ionization energy d. electronegative energy 21. For Group 2A metals, which electron is the most difficult to remove? a. the first b. the second c. the third d. All the electrons are equally difficult to remove. 22. In an endothermic reaction at equilibrium, what is the effect of raising the temperature? a. The reaction makes more products. c. The reaction is unchanged. b. The reaction makes more reactants. d. The answer cannot be determined. 23. In a reaction (at equilibrium) that makes more moles of gas than it consumes, what is the effect of increasing the pressure? a. The reaction makes more products. c. The reaction is unchanged. b. The reaction makes more reactants. d. The answer cannot be determined. 24. Which of the changes listed below would shift the following reaction to the right? 4HCl(g) + O (g) 2Cl (g) + 2H O(g) a. addition of Cl c. increase of pressure b. removal of O d. decrease of pressure 25. What is the equilibrium constant for the following reaction? C + O CO

3 a. c. b. d. 26. The K of a reaction is At equilibrium, the. a. reactants are favored b. products are favored c. reactants and products are present in equal amounts d. rate of the forward reaction is much greater than the rate of the reverse reaction 27. Why does a higher temperature cause a reaction to go faster? a. There are more collisions per second only. b. Collisions occur with greater energy only. c. There are more collisions per second and the collisions are of greater energy. d. There are more collisions per second or the collisions are of greater energy. 28. Why does a higher concentration make a reaction faster? a. There are more collisions per second only. b. Collisions occur with greater energy only. c. There are more collisions per second and the collisions are of greater energy. d. There are more collisions per second or the collisions are of greater energy. 29. What happens to a catalyst in a reaction? a. It is unchanged. c. It is incorporated into the reactants. b. It is incorporated into the products. d. It evaporates away. 30. A catalyst works by. a. lowering the activation energy barrier b. shifting the equilibrium position toward the products c. changing the temperature of the reactants d. changing the particle size of the reactants 31. The rate of a chemical reaction normally. a. decreases as temperature increases b. is slowed down by a catalyst c. increases as reactant concentration increases d. decreases as reactant concentration increases 32. Which of the following substances act as catalysts in the body? a. carbohydrates c. lipids b. nucleic acids d. enzymes 33. At equilibrium, what is the rate of production of reactants compared with the rate of production of products? a. much higher c. the same b. higher d. lower 34. If a reaction is reversible, what are the relative amounts of reactant and product at the end of the reaction? a. no reactant; all product b. no product; all reactant c. some product; some reactant d. The relationship between reactants and products cannot be determined. 35. Consider the reaction N (g) 3H (g) 2NH (g). What is the effect of decreasing the volume on the contained gases? a. The reaction shifts toward the product gas.

4 b. The system reacts by increasing the number of gas molecules. c. The pressure on the gases decreases momentarily. d. Ammonia is consumed in the reaction. 36. What are the acids in the following equilibrium reaction? CN + H O HCN + OH a. CN, H O c. CN, OH b. H O, HCN d. H O, OH 37. If the hydrogen ion concentration of a solution is 10 M, is the solution acidic, alkaline, or neutral? a. acidic c. neutral b. alkaline d. The answer cannot be determined. 38. The products of self-ionization of water are. a. H O and H O c. OH and H b. OH and OH d. OH and H 39. In a neutral solution, the [H ] is. a. 10 M c M b. zero d. equal to [OH ] 40. What is the best description for a solution with a hydroxide-ion concentration of 1 10 M? a. acidic c. neutral b. basic d. The answer cannot be determined. 41. The acid dissociation constant for an acid dissolved in water is equal to the. a. equilibrium constant b. equilibrium constant times the concentration of water c. equilibrium constant divided by the concentration of water d. equilibrium constant times the equilibrium constant of water 42. What is another name for the acid dissociation constant? a. equilibrium constant c. rate constant b. ionization constant d. mole fraction 43. Acetic acid ionizes in water as follows: Fewer than 1% of ethanoic acid molecules are ionized at any instant. The acetate ion (CH COO ) is therefore. a. a poor hydrogen-ion acceptor c. a poor hydrogen-ion donor b. a good hydrogen-ion acceptor d. a good hydrogen-ion donor 44. A 0.12M solution of an acid that ionizes only slightly in solution would be termed. a. concentrated and weak c. dilute and weak b. strong and dilute d. concentrated and strong 45. A substance with a K of 1 10 would be classified as a. a. strong acid c. strong base b. weak acid d. weak base 46. The ionization constant (K ) of HF is Which of the following is true in a 0.1M solution of this acid? a. [HF] is greater than [H ][F ]. c. [HF] is equal to [H ][F ]. b. [HF] is less than [H ][F ]. d. [HF] is equal to [H ][F ]. 47. If an acid has a K = , what is the acidity of the solution?

5 a. acidic c. neutral b. basic d. The answer cannot be determined. 48. The K of carbonic acid is H CO H + HCO This means that H CO is a. a. good hydrogen-ion acceptor c. good hydrogen-ion donor b. poor hydrogen-ion acceptor d. poor hydrogen-ion donor 49. A base has a K of Which of the following statements is true? a. This is a concentrated base. b. This base ionizes slightly in aqueous solution. c. This is a strong base. d. An aqueous solution of this base would be acidic. 50. The process of adding a known amount of solution of known concentration to determine the concentration of another solution is called. a. neutralization c. titration b. hydrolysis d. buffer capacity 51. In a titration, when the number of moles of hydrogen ions equals the number of moles of hydroxide ions, what is said to have happened? a. The equivalence point has been reached. b. The end point has been reached. c. The point of neutralization has been reached. d. The titration has failed. Short Answer 52. What is the electron configuration of Br 1-? 53. What is the electron configuration of Barium? 54. A mixture of hydrogen and iodine are in equilibrium with hydrogen iodide, as shown in the following equation. H + I 2HI Calculate the concentration of HI when the equilibrium constant is 1 is 0.04M, and the equilibrium concentration of I is 0.009M. 55. Calculate the value of K for the following reaction at equilibrium. 10, the equilibrium concentration of H 2NClO(g) 2NO(g) + Cl (g) An analysis of the equilibrium mixture in a 1-L flask gives the following results: NClO, 1.6 mol; NO, 6.4 mol; Cl, 0.49 mol 56. What is the approximate concentration of aluminum ions if the solubility product constant of Al(OH) is 27 10? 57. A 0.500M solution of a weak acid, HX, is only partially ionized. The [H ] was found to be M. Find the dissociation constant for this acid. Essay

6 58. Predict the effect of the following changes on the reaction in which SO 3 Decomposes to form SO 2 and O 2 2SO 3 (g) 2 SO 2 (g) + O 2 (g)! H" = kj a) increasing the temperature of the reaction b) incredasing the pressure on the reaction c) adding more O 2 when the reaction is at equilibrium. d) removing O 2 when the reaction is at equilibrium 59. Describe the trends in the atomic size of elements within groups and across periods in the periodic table. Specifically state the reasons for the size changes of atoms as you go across the periods left to right AND State the reasons why atoms increase in size Explain the size changes of atoms when they form ions. What happens to the size of positive ions and negative ions. 61. Graph the following data onto the graph and answer the following questions using Beer s law. The data and the graph grid are on the answer sheet. 62. Go to the question on Le Chatelier s principle and follow the lab instructions. Then answer the questions based on your observations of the change in color of a system at equilibrium

7 Science Olympiad Regional UW-Milwaukee Chemistry test 2013 Answer Section MULTIPLE CHOICE 1. ANS: A DIF: L1 REF: p. 164 OBJ: ANS: A DIF: L2 REF: p. 157 OBJ: ANS: D DIF: L1 REF: p. 156 OBJ: ANS: C DIF: L1 REF: p. 158 OBJ: ANS: C DIF: L2 REF: p. 164 OBJ: STO: D ANS: A DIF: L2 REF: p. 164 OBJ: STO: D ANS: B DIF: L1 REF: p. 171 OBJ: ANS: A DIF: L2 REF: p. 171 OBJ: ANS: A DIF: L2 REF: p. 171 OBJ: STO: D ANS: B DIF: L2 REF: p. 171 OBJ: ANS: A DIF: L3 REF: p. 171 OBJ: ANS: B DIF: L3 REF: p. 171, p. 175 OBJ: ANS: D DIF: L2 REF: p. 162, p. 163, p. 172, p. 176 OBJ: ANS: A DIF: L2 REF: p. 173 OBJ: ANS: B DIF: L3 REF: p. 162, p. 163, p. 172 OBJ: ANS: B DIF: L3 REF: p. 162, p. 163, p. 172 OBJ: ANS: A DIF: L1 REF: p. 177 OBJ: ANS: D DIF: L1 REF: p. 177 OBJ: ANS: A DIF: L2 REF: p. 175 OBJ: ANS: B DIF: L2 REF: p. 173 OBJ: ANS: C DIF: L2 REF: p. 173 OBJ: ANS: A DIF: L2 REF: p. 554 OBJ: STO: D ANS: B DIF: L2 REF: p. 554 OBJ: ANS: C DIF: L2 REF: p. 554 OBJ: ANS: B DIF: L1 REF: p. 556 OBJ: ANS: A DIF: L1 REF: p. 556 OBJ: ANS: C DIF: L1 REF: p. 545 OBJ: STO: D ANS: A DIF: L1 REF: p. 545 OBJ: ANS: A DIF: L1 REF: p. 546 OBJ: ANS: A DIF: L1 REF: p. 546 OBJ: ANS: C DIF: L1 REF: p. 545 OBJ: ANS: D DIF: L2 REF: p. 547 OBJ: ANS: C DIF: L1 REF: p. 550 OBJ:

8 34. ANS: C DIF: L1 REF: p. 549, p. 550 OBJ: ANS: A DIF: L2 REF: p. 554 OBJ: ANS: B DIF: L2 REF: p. 591 OBJ: STO: D ANS: B DIF: L1 REF: p. 595 OBJ: ANS: D DIF: L1 REF: p. 594 OBJ: ANS: D DIF: L1 REF: p. 595 OBJ: ANS: B DIF: L1 REF: p. 598 OBJ: ANS: B DIF: L1 REF: p. 607 OBJ: ANS: B DIF: L2 REF: p. 607 OBJ: ANS: B DIF: L3 REF: p. 609 OBJ: ANS: C DIF: L3 REF: p. 609 OBJ: ANS: B DIF: L2 REF: p. 607 OBJ: ANS: A DIF: L2 REF: p. 607 OBJ: ANS: D DIF: L2 REF: p. 610 OBJ: ANS: D DIF: L3 REF: p. 607 OBJ: ANS: B DIF: L3 REF: p. 608 OBJ: ANS: C DIF: L1 REF: p. 613, p. 614, p. 615 OBJ: ANS: A DIF: L1 REF: p. 613, p. 614, p. 615 OBJ: SHORT ANSWER 52. ANS: Krypton DIF: L2 REF: p. 162, p. 166 OBJ: ANS: Xe 6s 2 DIF: L2 REF: p. 166 OBJ: ANS: K = [HI] = [HI] = [HI] = 6M DIF: L3 REF: p. 559 OBJ: ANS: K =

9 = 7.8 DIF: L3 REF: p. 556, p. 557 OBJ: ANS: 10 M DIF: L3 REF: p. 562 OBJ: ANS: [HX] = 0.500M M = 0.496M K = = = M DIF: L3 REF: p. 607 OBJ: ESSAY 58. ANS: a)favors reactants b)lower mole amount favors reactants c)favors a shift to the reactants d) favors a shift to the products. 59. ANS: Atomic size increases with increasing atomic number within a group. For example, sodium atoms are larger than lithium atoms, and potassium atoms are larger than sodium atoms. Atomic size decreases with increasing atomic number across a period. For example, lithium atoms are larger than beryllium atoms, and beryllium atoms are larger than boron atoms. The atoms get larger at the start of the period in the alkali metals group. The noble gas core (shell) shields the positive nucleus from the outmost electrons allowing for the electron to be less attracted to the nucleus making the electron cloud (orbitals) larger. Then across the period the increase in nuclear charge draws in the electrons making the atoms smaller until they get to the noble gases, then the effect repeats itself for the next principal energy level. DIF: L2 REF: p. 171 OBJ: STO: D ANS: When an electron is added to an atom, the attraction of the nucleus for any one electron decreases and the size of the ion s radius increases. When an electron is removed from an atom, there is an increase in the nuclear attraction experienced by the remaining electrons. Consequently, the remaining electrons are drawn closer to the nucleus. DIF: L3 REF: p. 176 OBJ: STO: D ANS: The concentration of the solution the has the absorbance of 0.60

10 is 0.24M 62. ANS: The addition of Fe ion will favor a shift the products DARK red The addition of AgNO3 will favor a shift towards the reactant side Less dark, yellow The addition of KCl The addition of NaOH will favor a shift towards the reactant side as the OH ion reacts with the iron ion in the reactant side.

Periodic Trends. Name: Class: Date: ID: A. Matching

Periodic Trends. Name: Class: Date: ID: A. Matching Name: Class: Date: Periodic Trends Matching Match each item with the correct statement below. a. electronegativity f. periodic law b. ionization energy g. atomic mass c. atomic radius h. period d. metal