January 1, 2009

化學50題&新年快樂

練習題 郭培中博士出題
.Calculate the volume in mL of a 1.420 M NaOH solution required to titrate 25.00 mL of a 1.500 M H3PO4 solution.
(A) 112.5 mL (B) 26.41 mL (C) 79.23 mL (D) 50.00 mL
.What volume of a 0.500 M HCl solution is needed to completely neutralize 10.0 mL of a 0.300 M NaOH solution?
(A) 6.00 mL (B) 0.300 mL (C) 10.0 mL (D) 3.00 mL
.Iodate ion, IO3-, oxidizes SO32- in acidic solution. The half-reaction for the oxidation is SO32– + H2O  SO42– + 2H+ + 2e–
A 100.0-mL sample of solution containing 1.390 g of KIO3 reacts with 32.5 mL of 0.500 M Na2SO3. What is the final oxidation state of the iodine after the reaction has occurred?
(A) +7 (B) +1 (C) 0 (D) –1
.What volume of a 0.500 M HCl solution is needed to completely neutralize 10.0 mL of a 0.200 M Ba(OH)2 solution?
(A) 10.0 mL (B) 0.200 mL (C) 2.00 mL (D) 8.00 mL
. A 46.2-mL, 0.568 M calcium nitrate [Ca(NO3)2] solution is mixed with 80.5 mL of 1.396 M calcium nitrate solution. Calculate the concentration of the final solution.
(A) 1.96 M (B) 1.09 M (C) 0.982 M (D) 2.25 M
.The density of ethanol, a colorless liquid that is commonly known as grain alcohol, is 0.798 g/mL. Calculate the mass of 17.4 mL of the liquid?
(A)13.9 g (B)21.8 g (C)7.20 × 10–2 g (D)4.59 × 10–2 g
. How many grams of KOH are present in 35.0 mL of a 5.50 M solution?
(A) 10.8 g (B) 0.193 g (C) 1.96 g (D) 308 g
.What temperature is 95 °F when converted to degrees Celsius?
(A)63 °C (B)35 °C (C)127 °C (D)15 °C
.Which of the following measurements has five significant figures?
(A)4867 mi (B)56 mL (C)60,104 ton (D)0.00003 cm
. Arrange the following species in order of increasing oxidation number of the sulfur atom: (a) H2S, (b) S8, (c) H2SO4, (d) S2–.
(A) (a) < (d) < (b) < (c) (B) (a) = (d) < (b) < (c)
(C) (c) < (b) < (d) < (a) (D) (b) < (d) = (a) < (c)
.How many significant figures are there in 0.006 L?
(A)1 (B)2 (C)3 (D)4
. The atomic masses of Li and Li are 6.0151 amu and 7.0160 amu, respectively. Calculate the natural abundances of these two isotopes. The average atomic mass of Li is 6.941 amu.
(A) 6Li = 7.5 %; 7Li = 92.5 % (B) 6Li = 0.075 %; 7Li = 99.025 %
(C) 6Li = 92.5 %; 7Li = 7.5 % (D) 6Li = 25 %; 7Li = 75 %
.Grape juice is an example of a:
(A)substance (B)heterogeneous mixture
(C)element (D)homogeneous mixture
. A sample of 0.6760 g of an unknown compound containing barium ions (Ba2+) is dissolved in water and treated with an excess of Na2SO4. If the mass of the BaSO4 precipitate formed is 0.4105 g, what is the percent by mass of Ba in the original unknown compound?
(A) 35.72 % (B) 24.15 % (C) 64.28 % (D) 2.663 %
.Water is an example of a:
(A)compound (B)heterogeneous mixture
(C)element (D)homogeneous mixture
. How many moles of MgCl2 are present in 60.0 mL of 0.100 M MgCl2 solution?
(A) 60.0 moles (B) 0.572 moles
(C) 6.00 × 10–3 moles (D) 6.00 moles
.Which of the following is an intensive property?
(A)mass (B)volume (C)density (D)length
. Calculate the volume in mL required to provide 4.30 g of ethanol from a 1.50 M solution.
(A) 2.87 mL (B) 30.7 mL (C) 22.3 mL (D) 62.2 mL
. Calculate the volume in mL of a 1.420 M NaOH solution required to titrate 25.00 mL of a 2.430 M HCl solution.
(A) 60.75 mL (B) 42.78 mL (C) 17.61 mL (D) 22.43 mL
. Ammonium nitrate (NH4NO3) is one of the most important nitrogen-containing fertilizers. Its purity can be analyzed by titrating a solution of NH4NO3 with a standard NaOH solution. In one experiment a 0.2041-g sample of industrially prepared NH4NO3 required 24.42 mL of 0.1023 M NaOH for neutralization. What is the percent purity of the sample?
(A) 75.43 % (B)97.99 % (C) 99.79 % (D) 79.90 %
.Calculate the volume in mL of a 1.420 M NaOH solution required to titrate 25.00 mL of a 4.500 M H2SO4 solution.
(A) 56.25 mL (B) 158.5 mL (C) 112.5 mL (D) 225.0 mL


.The alcohol content in a 10.0-g sample of blood from a driver required 4.23 mL of 0.07654 M K2Cr2O7 for titration. What is the percent alcohol by mass in the driver's blood? The reaction equation is given by:
3CH3CH2OH + 2K2Cr2O7 + 8H2SO4 
3CH3COOH + 2Cr2(SO4)3 + 2K2SO4 + 11H2O
(A) 0.149 % (B) 0.298 % (C) 0.224 % (D) 0.443%
.What is the number of protons and the number of neutrons in the nucleus of ?
(A)25 protons, 12 neutrons (B)13 protons, 12 neutrons
(C)12 protons, 25 neutrons (D)12 protons, 13 neutrons
. Which of the following is a correct half-reaction for the reaction: 2Sr + O2  2SrO
(A) Sr  Sr+ + e– (B) Sr + 2e–  Sr2–
(C) Sr  Sr2+ + 2e– (D) Sr + e–  Sr–
.What is the number of protons, neutrons, and electrons in ?
(A)29 protons, 34 neutrons, 34 electrons
(B)29 protons, 34 neutrons, 29 electrons
(C)34 protons, 29 neutrons, 34 electrons
(D)29 protons, 63 neutrons, 29 electrons
.The atomic masses of Cl (75.53 percent) and Cl (24.47 percent) are 34.968 amu and 36.956 amu, respectively. Calculate the average atomic mass of chlorine. The percentages in parentheses denote the relative abundances.
(A) 35.96 amu (B) 35.45 amu (C) 36.47 amu (D) 71.92 amu
.What is the difference between an atom and a molecule?
(A)A molecule has more electrons than an atom.
(B)An atom is charged while a molecule is not.
(C)A molecule is an aggregate of atoms, while an atom, by definition, is a single particle.
(D)A molecule is bigger than an atom.
. Which of the following equations is balanced?
(A) 2C + O2  CO (B) 2CO + O2  2CO2
(C) H2 + Br2  HBr (D) 2K + H2O  2KOH + H2
.How are allotropes different from isotopes?
(A)Allotropes are ionic, while isotopes are not.
(B)Allotropes are gases, while isotopes are generally solids.
(C)Allotropes are single atoms, while isotopes are aggregates of atoms.
(D)Allotropes are different molecular combinations of a single element; isotopes are atoms of the same element with different masses.

. Which of the following scientists experimentally determined the charge of an electron?
(A) J. J. Thomson (B) R. A. Millikan
(C) Ernest Rutherford (D) James Chadwick
. What is the number of protons and the number of neutrons in the nucleus of ?
(A) 25 protons, 12 neutrons (B) 13 protons, 12 neutrons
(C) 12 protons, 25 neutrons (D) 12 protons, 13 neutrons

Use the following to answer questions 17-21:
ATOM OR ION OF ELEMENT A B C D E F G
Number of electrons 5 10 18 28 36 5 9
Number of protons 5 7 19 30 35 5 9
Number of neutrons 5 7 20 36 46 6 10

..Which of the species are neutral?
(A) C (B) A and B (C) A, F and G (D) E
.Which of the species are negatively charged?
(A) C and D (B) D, E and G (C) A and D (D) B and E
..Which of the species are positively charged?
(A) C and D (B) B and E (C) A, C and F (D) G
..What are the conventional symbols for species C and F?
(A) , (B) ,
(C) , (D) ,
.What is the appropriate symbol for the isotope Z = 11, A = 23?
(A) (B) (C) (D)
.What mass of NH3 (in g) must be used to produce 1.00 ton of HNO3 by the above procedure, assuming an 80 percent yield in each step?
(1 ton = 2000 lb; 1 lb = 453.6 g.)
(A) 9.6 ´ 105 g (B) 1.2 ´ 106 g
(C) 1.5 ´ 106 g (D) 1.9 ´ 106 g

.Group the following elements in pairs that you would expect to show similar chemical properties: K, F, P, Na, Cl, and N.
(A)K/N; F/Na; Cl/N (B)K/Na; F/Cl; P/N
(C)K/F; P/Na; Cl/N (D)K/P; F/Na; Cl/N
.NH4+ is an example of which of the following?
(A)a monatomic cation (B)a monatomic anion
(C)a polyatomic cation (D)a polyatomic anion
. A quantity of 25.0 mL of a solution containing both Fe2+ and Fe3+ ions is titrated with 23.0 mL of 0.0200 M KMnO4 (in dilute sulfuric acid). As a result, all of the Fe2+ ions are oxidized to Fe3+ ions. Next, the solution is treated with Zn metal to convert all of the Fe3+ ions to Fe2+ ions. Finally, the solution containing only the Fe2+ ions requires 40.0 mL of the same KMnO4 solution for oxidation to Fe3+. Calculate the molar concentrations of Fe2+ and Fe3+ in the original solution. The net ionic equation is: (MW for Mn =55,Fe=56)
MnO4– + 5Fe2+ + 8H+  Mn2+ + 5Fe3+ + 4H2O
(A) [Fe2+] = 0.0920 M; [Fe3+] = 0.0920 M
(B) [Fe2+] = 0.0920 M; [Fe3+] = 0.0680 M
(C) [Fe2+] = 0.0680 M; [Fe3+] = 0.0920 M
(D) [Fe2+] = 0.0680 M; [Fe3+] = 0.0680 M
.A 1.00-g sample of a metal X (that is known to form X2+ ions) was added to 0.100 liter of 0.500 M H2SO4. After all the metal had reacted, the remaining acid required 0.0334 L of 0.500 M NaOH solution for neutralization. Calculate the molar mass of the metal and identify the element.
(A)48.0 g/mol; Ti (B)40.1 g/mol; Ca
(C)24.0 g/mol; Mg (D)55.9 g/mol; Fe
. Allicin is the compound responsible for the characteristic smell of garlic. An analysis of the compound gives the following percent composition by mass: C: 44.4 percent; H: 6.21 percent; S: 39.5 percent; O: 9.86 percent. What is its molecular formula given that its molar mass is about 162 g?
(A) C12H20S4O2 (B) C7H14SO
(C) C6H10S2O (D) C5H12S2O2
.Consider the reactionMnO2 + 4HCl ® MnCl2 + Cl2 + 2H2OIf 0.86 mole of MnO2 and 48.2 g of HCl react, how many grams of Cl2 will be produced?
(A) 42.3 g (B) 93.6 g (C) 63.4 g (D) 23.4 g

.When 2.50 g of a zinc strip were placed in a AgNO3 solution, silver metal formed on the surface of the strip. After some time had passed, the strip was removed from the solution, dried, and weighed. If the mass of the strip was 3.37 g, calculate the mass of Ag and Zn metals present. (MW for Zn =65, Ag=108)
(A) 1.69 g Ag; 1.69 g Zn (B) 3.37 g Ag, 0.00 g Zn
(C) 0.87 g Ag; 2.50 g Zn (D) 1.25 g Ag; 2.12 g Zn
.Calculate the concentration of the acid (or base) remaining in solution when 10.7 mL of 0.211 M HNO3 are added to 16.3 mL of 0.258 M NaOH.
(A)0.0174 M HNO3 (B)0.0722 M NaOH
(C)0.235 M NaOH (D)0.240 M HNO3
.Acetylsalicylic acid (C9H8O4) is a monoprotic acid commonly known as “aspirin.” A typical aspirin tablet, however, contains only a small amount of the acid. In an experiment to determine its composition, an aspirin tablet was crushed and dissolved in water. It took 12.25 mL of 0.1466 M NaOH to neutralize the solution. Calculate the number of grains of aspirin in the tablet. (One grain = 0.0648 g.)
(A) 27.7 grains (B) 3.92 grains
(C) 4.99 grains (D) 2.77 grains
.Milk of magnesia is an aqueous suspension of magnesium hydroxide [Mg(OH)2] used to treat acid indigestion. Calculate the volume of a 0.035 M HCl solution (a typical acid concentration in an upset stomach) needed to react with two spoonfuls (approximately 10 mL) of milk of magnesia [at 0.080 g Mg(OH)2/mL].
(A)2.5 L (B)0.80 L (C)0.035 L (D)0.028 L
.How many amu are there in 8.4 g?
(A) 8.4  1023 amu (B) 1.4  10-23 amu
(C) 8.4 amu (D) 2.663 %
.A 60.0-mL 0.513 M glucose (C6H12O6) solution is mixed with 120.0 mL of 2.33 M glucose solution. What is the concentration of the final solution? Assume the volumes are additive.
(A)1.73 M (B)1.42 M (C)3.48 M (D)2.25 M
..Industrially, nitric acid is produced by the Ostwald process represented by the following equations:
4NH3(g) + 5O2(g)  4NO(g) + 6H2O(l)
2NO(g) + O2(g)  2NO2(g)
2NO2(g) + H2O(l)  HNO3(aq) + HNO2(aq)

. Propane (C3H8) is a component of natural gas and is used in domestic cooking and heating. The balanced equation for the combustion of propane is:C3H8 + 5O2
3CO2 + 4H2OHow many grams of carbon dioxide can be produced by burning 3.65 moles of propane? Assume that oxygen is the excess reagent in this reaction.
(A) 161 g (B) 11.0 g (C) 332 g (D) 482 g

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Reply
  • 1樓

    1樓搶頭香

    我寫到快瘋了....

    有些根本有看沒有懂!!

    去他的化學老師!!!!!

  • oceanhope at January 2, 2009 06:33 PM comment | prosecute
  • 2樓

    2樓頸推

    題目有些很怪~題目不完全
    可以提供一些意見嗎?

  • evildoer520 at January 2, 2009 09:09 PM comment | prosecute
  • 3樓

    3樓坐沙發

    有誰寫完可以對一下答案@.@
    以下是我的答案~
    http://www.wretch.cc/blog/vagrantwalte/7009984
    請大家多多指教> <"

  • vagrantwalte at January 3, 2009 04:10 PM comment | prosecute
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