1.A mixture of two gases was allowed to effuse from a container. One of the gases escaped from the container 1.43 times as fast as the other one. The two gases could have been __________.
A:O2 and Cl2
B:Cl2 and SF6
C:CO and SF6
D:CO and CO2
E:O2 and SF6
答案:Cl2 and SF6
2.A neutralization reaction between an acid and a metal hydroxide produces __________.
A:water and a salt
B:oxygen gas
C:sodium hydroxide
D:ammonia
E:hydrogen gas
答案:water and a salt
3.One edge of a cube is measured and found to be 13 cm. The volume of the cube in m3 is __________.
A:2.2 × 106
B:2.2 × 10-6
C:2.2 × 10-3
D:2.2 × 103
E:2.2
答案:AI参考:正确答案是B：2.2 × 10-6。\n题目中给出的是一个立方体的一个边长为13cm，即立方体边长为0.013m。体积 = 边长3，即V=a³=0.013m³。把立方米的符号³写下来就得到0.013³=V，所以V=2.2×10-6m³。因此，答案为B。'
4.The Ka of hypochlorous acid (HClO) is 3.00 × 10-8 at 25.0 °C. Calculate the pH of a 0.0385 M hypochlorous acid solution.
A:1.41
B:7.52
C:-1.41
D:4.47
E:8.94
答案:AI参考:正确答案是D：4.47。\n根据题目给出的信息，已知次氯酸（HClO）的电离常数Ka=3.00×10-8，溶液的浓度为0.0385M，根据pH的计算公式pH=-lg[H+]，其中[H+]表示氢离子浓度，可以求出氢离子浓度为10-4.47，即氢离子浓度约为4.47mol/L，因此溶液的pH约为4.47。所以答案为D。'
5.An aqueous solution of a soluble compound (a nonelectrolyte) is prepared by dissolving 33.2 g of the compound in enough water to form 250 mL of solution. The solution has an osmotic pressure of 1.2 atm at 25.0 °C What is the molar mass (g/mL) of the compound?
A:6.8 × 102
B:1.0 × 103
C:2.3 × 102
D:28
E:2.7 × 103
答案:AI参考:正确答案是【E:2.7 × 103】。\n\n根据题目描述，该溶液在25℃时的渗透压为1.2atm，即溶液中溶质分子对水的吸引力为1.2个大气压。已知溶质的质量为33.2g，溶液体积为250mL，可计算溶质的摩尔质量，再将其换算成单位为g/mL的摩尔质量值即可得出答案。由公式m = 摩尔质量M = 溶液的质量/溶液的体积，可求出摩尔质量，再乘以溶液的体积得到结果为：M = 33.2g / 0.25L = 132g/L = 2.7 × 103g/mL。因此，答案为E：2.7 × 103。'
6.Osmium has a density of 22.6 g/cm3. The mass of a block of osmium that measures 1.01 cm × 0.233 cm × 0.648 cm is __________ g.
A:148
B:34.5
C:3.45
D:6.75 × 103
E:6.75 × 10−3
答案:AI参考:正确选项为D：6.75 × 103。\n\n根据题目中的信息，Osnium的密度为22.6 g/cm3，而题目中给出的块状Osnium的尺寸为1.01 cm × 0.233 cm × 0.648 cm，将其转换为立方厘米得到0.101 × 0.233 × 0.648 = 0.0146288立方厘米。由于Osnium的密度已知，因此可以通过密度和体积的关系来计算质量，即质量 = 密度 × 体积。将上述数据带入公式，得到质量 = 22.6 g/cm3 × 0.0146288立方厘米 = 6.75 × 10^3克。所以选项D是正确的。'
7.The mass % of Al in aluminum sulfate (Al2 (SO4)3) is __________.
A:15.77
B:21.93
C:45.7
D:35.94
E:7.886
答案:AI参考:正确答案是D：35.94。\n铝离子（Al 2(SO4)3）中的铝元素质量分数为35.94%。\n\n解析：铝离子是由铝原子失去3个电子形成的，而硫酸根离子是由硫原子和氧原子形成的一个整体，所以铝元素的质量分数是铝原子的质量分数与硫酸根中氧元素的质量分数之和再除以铝离子的相对分子质量，即：\n\n铝元素的质量分数 = (2 * 27) / (2 * 27 + 3 * 2 + 32 * 4) = 35.94%\n\n所以答案为D。'
8.How many molecules of CH4 are in 48.2 g of this compound?
A:2.90 × 1025
B:3
C:1.81 × 1024
D:4
E:5.00 × 1024
答案:AI参考:正确答案是【C:1.81 × 1024 】。\n\n根据题目，需要求出48.2克这种化合物中CH4分子的数量。根据摩尔质量的概念，$n = m/M$，$n$为物质的量，$m$为质量，$M$为摩尔质量。$CH_{4}$的摩尔质量为$16g/mol$，所以物质的量为$n = m/M = 48.2g / 16g/mol = 3.01\times 10^{23}$个。因此，正确答案为C：$1.81 \times 10^{24}$。'
9.An object will sink in a liquid if the density of the object is greater than that of the liquid. The mass of a sphere is 9.83 g. If the volume of this sphere is less than __________ cm3 , then the sphere will sink in liquid mercury (density = 13.6 g/cm3).
A:134
B:7.48
C:1.38
D:0.723
E:none of the above
答案:AI参考:正确答案是【B:7.48】。\n\n题目中给出了球的密度大于液体的密度，所以球会下沉。已知球的密度为9.83克/立方厘米，液体汞的密度为13.6克/立方厘米，为了使球下沉，球的实际体积需要小于13.6克/立方厘米 × 10-6厘米3=7.48立方厘米。因此，答案为B。'
10.Which of the following are combination reactions? 1) CH4 (g) + O2 (g) → CO2 (g) + H2O (l); 2) CaO (s) + CO2 (g) → CaCO3 (s); 3) Mg (s) + O2 (g) → MgO (s); 4) PbCO3 (s) → PbO (s) + CO2 (g)
A:1, 2, and 3
B:2, 3, and 4
C:1, 2, 3, and 4
D:4 only
E:2 and 3
答案:AI参考:正确选项是E:2 and 3。\n\n这些反应分别是：\n\n1）甲烷与氧气反应生成二氧化碳和水蒸气，这是燃烧反应；\n\n2）氧化钙与二氧化碳反应生成碳酸钙，这是固体的碳酸钙在高温下的分解反应；\n\n3）镁与氧气反应生成氧化镁，这是金属镁的氧化反应；\n\n这三个反应都属于分解反应和氧化还原反应，而选项D只提到了第四个反应，即碳酸铅分解为氧化铅和二氧化碳，所以不正确。因此，答案为E：2和3。'
11.What is the coefficient of O2 when the following equation is completed and balanced? C4H8O2 + O2 → ________
A:3
B:5
C:1
D:6
E:2
A:2.01 B:16.3 C:0.497 D:0.247 E:4.04 13.A 0.100 m solution of which one of the following solutes will have the lowest vapour pressure?
A:Ca(ClO4)2 B:KClO4 C:Al(ClO4)3 D:NaCl E:sucrose 14.One mole of __________ contains the largest number of atoms.
A:Na3PO4 B:C10H8 C:Cl2 D:Al2 (SO4)3 E:S8 15.The transition metals in group __________ have the highest melting points.
A:4 B:2 C:3 D:6 E:8 16.Which of the following are chemical processes? 1. rusting of a nail 2. freezing of water 3. decomposition of water into hydrogen and oxygen gases 4. compression of oxygen gas.
A:1, 3, 4 B:1, 3 C:2, 3, 4 D:1, 2 E:1, 4 17.Predict the product in the combination reaction below. Al (s) + N2 (g) → ________
A:AlN2 B:Al3N C:AlN3 D:AlN E:Al3N2 18.The common-ion effect refers to the observation __________.
A:that some ions, such as Na+ (aq), frequently appear in solutions but do not participate in solubility equilibria 19.Which hydroxides are strong bases?
A:KOH, Ba(OH)2 B:KOH, NaOH, Ba(OH)2 C:None of these is a strong base D:Sr(OH)2 , KOH, NaOH, Ba(OH)2 E:KOH, NaOH 20.Cl2 (g) + H2O (l) → ________
A:2 HCl (aq) + O2- (g) B:2Cl- (aq) + H2O (l) C:HCl (aq) + HOCl (aq) D:2 HCl (aq) + O2 (g) E:Cl2 (aq) + H2O (l) 21.Which one of the following statements regarding Kw is false?
A:pKw is 14.00 at 25°C B:Kw changes with temperature C:Kw is known as the ion product of water D:The value of Kw shows that water is a weak acid E:The value of Kw is always 1.0 × 10-14. 22.Of the halogens, which are gases at room temperature and atmospheric pressure?
A:fluorine, chlorine, and bromine B:fluorine, chlorine, bromine, and iodine C:fluorine and chlorine D:fluorine, bromine, and iodine E:fluorine, chlorine, and iodine 23.Which alkaline earth metal will not react with liquid water or with steam __________?
A:Ca B:They all react with liquid water and with steam C:Mg D:Be E:Ba 24.Round the following number to four significant figures and express the result in standard exponential notation: 229.613.
A:229.6 B:22.96 × 10-1 C:2.296 × 102 D:2.296 × 10-2 E:0.2296 × 103 25.A closed-end manometer was attached to a vessel containing argon. The difference in the mercury levels in the two arms of the manometer was 12.2 cm. Atmospheric pressure was 783 mm Hg. The pressure of the argon in the container was __________ mm Hg.
A:795 B:771 C:122 D:661 E:882 26.A tin atom has 50 electrons. Electrons in the __________ subshell experience the lowest effective nuclear charge.
A:3d B:5s C:1s D:3p E:5p 27.The oxidation state of copper in Cu2CO3(OH)2 is __________.
A:-2 B:0 C:4 D:1 E:2 28.A strong electrolyte is one that __________ completely in solution.
A:decomposes B:disintegrates C:disappears D:reacts E:ionizes 29.1 nanometer = __________ picometers
A:1 B:0.1 C:10 D:0.01 E:1000 30.__________ solids consist of atoms or molecules held together by dipole-dipole forces, London dispersion forces, and/or hydrogen bonds.
A:Molecular B:Ionic C:Metallic and covalent-network D:Covalent-network E:Metallic 31.The correct name for Al2O3 is __________.
A:dialuminum trioxide B:aluminum trioxide C:aluminum oxide D:aluminum hydroxide E:dialuminum oxide 32.On the phase diagram above, segment __________ corresponds to the conditions of temperature and pressure under which the solid and the gas of the substance are in equilibrium.
A:AB B:AD C:AC D:BC E:CD 33.In which of the following atoms is the 3s orbital closest to the nucleus?
A:The 3s orbitals are the same distance from the nucleus in all of these atoms. B:I C:Br D:Cl E:At 34.The formula weight of potassium dichromate (K2Cr2O7) is __________ amu.
A:242.18 B:294.18 C:255.08 D:107.09 E:333.08 35.Lattice energy is __________. The diagram below is the Born-Haber cycle for the formation of crystalline potassium fluoride.
A:the energy required to produce one mole of an ionic compound from its constituent elements in their standard states B:the energy required to convert a mole of ionic solid into its constituent ions in the gas phase C:the energy given off when gaseous ions combine to form one mole of an ionic solid D:the sum of ionization energies of the components in an ionic solid E:the sum of electron affinities of the components in an ionic solid 36.Which one of the following is a pure substance?
A:wood B:milk C:elemental copper D:saltwater E:concrete 37.The number 0.00430 has __________ significant figures.
A:2 B:6 C:3 D:5 E:4 38.__________ is the chemical symbol for elemental sodium.
A:So B:S C:Na D:Sn E:W 39.A combination of sand, salt, and water is an example of a __________.
A:homogeneous mixture B:pure substance C:heterogeneous mixture D:compound E:solid 40.CO2 from hydrocarbon combustion creates a major environmental problem that is described as __________.
A:all of the above B:acid rain C:stratospheric ozone depletion D:photochemical smog E:the greenhouse effect 41.Using Bohr's equation for the energy levels of the electron in the hydrogen atom, determine the energy (J) of an electron in the n = 4 level. __________ .
A:-10.6 B:-7472.12 C: -5.45 × 10-19 D:-47.4 E:-1.36 x 10-19 42.Of the following statements, __________ is not true for oxygen.
A:Oxygen is a colourless gas at room temperature. B:Oxygen forms peroxide and superoxide anions. C:The most stable allotrope of oxygen is O2. D:The chemical formula of ozone is O3. E:Dry air is about 79 % oxygen. 43.In which one of the following numbers are all of the zeros significant?
A:100.09009 B:0.14329 C:0.1 D:0.05843 E:0.003002 44.The de Broglie wavelength of a particle is given by __________.
A:h + mv B:h/mv C: mv D:mv/c E: hmv 45.What is the oxidation number of potassium in KMnO4?
A:3 B:2 C:0 D:1 E:-1 46.Predict the empirical formula of the ionic compound that forms from sodium and fluorine.
A:Na2F B:NaF2 C:NaF D:Na2F3 E:Na3F2
