Chemistry 1st 2023 PDF

# Science - 22 - 39 ## Chemistry **Marking Your Choice of Subject on the Answer Sheet** Choose and answer two subjects from Physics, Chemistry, and Biology. Use the other side for the answer sheet of one subject, and the reverse side for the other subject. As shown in the example on the right, if...

# Science - 22 - 39 ## Chemistry **Marking Your Choice of Subject on the Answer Sheet** Choose and answer two subjects from Physics, Chemistry, and Biology. Use the other side for the answer sheet of one subject, and the reverse side for the other subject. As shown in the example on the right, if you answer the Chemistry subjects, circle "Chemistry" and complete the oval under "Subject". **If you do not fill in the appropriate oval, your answers will be corrected.** | Example | |---|---| | < Subject > | | 物理 - 化學 | | Physics | Chemistry | | 生物 | | Biology | Unless noted otherwise, assume that all gases are ideal gases. * Use the following values for calculations. The unit of volume "liter" is represented by "L". * Standard state: 0 °C, 1.01 × 105 Pa (1 atm) * The molar volume of an ideal gas at the standard state: 22.4 L/mol * Gas constant: R = 8.31 J/(mol · K) * Avogadro constant: N_A = 6.02 × 10²³ /mol * Faraday constant: F = 9.65 × 10⁴ C/mol * Atomic weight: H: 1.0 He: 4.0 C: 12 N: 14 O: 16 S: 32 Si: 28 Fe: 59 The relation between the group, the period of elements used in this examination is indicated in the following periodic table. Atomic symbols other than H are omitted. | Period | Group | |---|---| | 1 | 1 | 2 | | 2 | | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | | 3 | | | | | | | | | | | | | | | | | | | 4 | | | | | | | | | | | | | | | | | | | 5 | | | | | | | | | | | | | | | | | | # Science - 24 - Science -39 ## Science - 24 ### Q1 Among the following molecules and ions a-d, there are two in which the total number of electrons are the same. From ①⑥ below choose the correct combination. 1. a. F₂ b. NH₃ c. Li⁺ d. OH^- ① a, b ② a, c ③ a, d ④ b, c ⑤ b, d ⑥ c, d ## Science -25 ### Q2 The elemental analysis of a compound consisting of two elements A and B was carried out. The composition by mass was 71% A and 29% B. The atomic weight of A is 1.21 times as large as that of B. From ①⑦ below choose the correct compositional formula of this compound. 2 ① AB ② AB₂ ③ AB₃ ④ A₂B ⑤ A₂B₃ ⑥ A₃B ⑦ A₃B₂ ## Science - 26 ### Q3 Among the following molecules a-e, two are nonpolar though they have polar bond(s) in the molecule. From 1-6 below choose the correct combination. 3 a. water b. nitrogen c. ammonia d. carbon dioxide e. tetrachloromethane ① a, c ② a, e ③ b, d ④ b, e ⑤ c, d ⑥ d, e ## Science - 27 ### Q4 Suppose there is a gas mixture of methane (CH₄) and ethane (C₂H₆), the volume ratio of which is 1:1 at the same temperature and pressure. When a sufficient amount of oxygen (O₂) was added and the mixture was completely combusted, 36 g of water (H₂O) was generated. From - in the table below, choose the correct combination of the closest values for the total amount of the gas mixture in mol and the mass (g) of generated carbon dioxide (CO₂). 4 | Total amount of the gas mixture (mol) | Mass of carbon dioxide (g) | |:--:|:--:| | 0.40 | 18 | | 0.40 | 35 | | 0.40 | 53 | | 0.80 | 18 | | 0.80 | 35 | | 0.80 | 53 | ## Science - 28 ### Q5 Concerning the following statements on the separation procedure with the aid of a separatory funnel, choose the correct combination of terms which apply to blanks A and B from 1-6 in the table below. 5 A mixed aqueous solution of iodine and potassium iodide and hexane are added to a separatory funnel, and the funnel is shaken well, and left still. Then the aqueous solution and hexane are separated in two layers. Since iodine is more readily soluble in hexane than in water, most of the iodine dissolves in the hexane. The separation procedure taking advantage of the difference in solubility is known as A and the hexane solution corresponds to the B in the following drawing. | A | B | |---|---| | recrystallization | upper layer | | extraction | upper layer | | filtration | upper layer | | recrystallization | lower layer | | extraction | lower layer | | filtration | lower layer | ## Science - 29 ### Q6 The following graph indicates the relation between the pressure and volume of 10 g of methane (CH₄) at 400 K. From ①④ below choose the gas that has the same relation between pressure and volume with this graph. 6 The graph shows a line that decreases rapidly for a short period of time, then levels off to become almost horizontal. | | |---| | ① 10 g of helium (He) at 200 K | | ② 10 g of helium at 800 K | | ③ 10 g of oxygen (O₂) at 200 K | | ④ 10 g of oxygen at 800 K | ## Science - 30 ### Q7 Suppose 2.52 g of oxalic acid hydrate ((COOH)₂.nH₂O) is dissolved in water to prepare 1.0 L of the aqueous solution. Suppose 0.050 mol/L of aqueous barium hydroxide (Ba(OH)₂) is added dropwise to 50 mL of this aqueous solution. The neutralization point is reached when 20 mL of the aqueous barium hydroxide is added. From 1-6 below choose the most appropriate one as the value of n. 7 ① 0.5 ② 1 ③ 2 ④ 3 ⑤ 4 ⑥ 5 ## Science - 31 ### Q8 Among the following reactions 1-6, choose the one in which the underlined atom is reduced and the change (in absolute value) of the oxidation number is the least. 8 ① SO₂ + 2 H₂S → 2 H₂O + 3 S ② 2Cu + 2 H₂SO₄ → CuSO₄ + 2 H₂O + SO₂ ③ CuCl₂ + H₂S → CuS + 2 HCl ④ H₂O₂ + SO₂ → H₂SO₄ ⑤ MnO₂ + 4 HCl → MnCl₂ + 2 H₂O + Cl₂ ⑥ 2 KMnO₄ + 5 H₂O₂ + 3 H₂SO₄ → 2 MnSO₄ + 5 O₂ + 8 H₂O + K₂SO₄ ## Science - 32 ### Q9 Suppose that 0.40 A of electric current was passed through aqueous nickel(II) sulfate for 4800 s with a copper plate acting as a cathode and a nickel plate acting as an anode. Assume that the combined area of both surfaces of the copper plate is 40 cm². From - below choose the most appropriate value for the average thickness of the nickel deposited on the copper plate in cm. Assume that the density of metallic nickel is 8.9 g/cm³ and that the area of all four edges of the copper plate is negligible. 9 cm ① 3.3×10^-4 ② 1.7×10^-3 ③ 3.3×10^-3 ④ 6.6×10^-3 ⑤ 1.7×10^-2 ⑥ 6.6×10^-2 ## Science - 33 ### Q10 A reversible reaction in which gases B and C are generated from gas A is represented by reaction formula (i) where a, b, and c are coefficients. a A → bB + cC (i) Suppose B and C are formed from a fixed amount of A and reach an equilibrium state. The curves plotted in the following graph show the pressure dependence of the volume percent (%) of A in the gas mixture at equilibrium at different temperatures. It is clear from the graph that the forward reaction of reaction (i) is an X and the relation among a, b, and c is Y . From in the table below choose the correct combination of term and relation which fits blanks X and Y. 10 The graph shows three curves that decrease as pressure increases. As temperature increases, the curves shift to the right. | X | Y | |---|---| | endothermic reaction | a > b + c | | endothermic reaction | a = b + c | | endothermic reaction | a < b + c | | exothermic reaction | a > b + c | | exothermic reaction | a = b + c | | exothermic reaction | a < b + c | ## Science - 34 ### Q11 Among the following statements a-d on helium, neon, and argon, all belonging to Group 18 in the periodic table, two are correct. From ①⑥ below choose the correct combination. 11 a. For all atoms of these elements the number of outermost shell electrons is 8. b. The boiling point of helium is the lowest among all substances. c. At normal temperature and pressure, the density of gaseous neon is larger than that of fluorine, but smaller than that of chlorine. d. Among helium, neon, and argon, the one that is most abundant in air is argon. ① a, b ② a, c ③ a, d ④ b, c ⑤ b, d ⑥ c, d ## Science - 35 ### Q13 Among the following gases -⑤, choose the one that is most appropriately collected by downward delivery. 13 ① the gas generated by adding dilute sulfuric acid (H₂SO₄) to iron(II) sulfide (FeS) ② the gas generated by adding dilute nitric acid (HNO₃) to copper (Cu) ③ the gas generated by adding sodium hydroxide (NaOH) to sodium acetate (CH₃COONa) and heating the mixture ④ the gas generated by adding concentrated sulfuric acid (H₂SO₄) to formic acid (HCOOH) and heating the mixture ⑤ the gas generated by adding concentrated sulfuric acid to ethanol (C₂H₅OH) and heating the mixture to 170 °C ## Science - 36 ### Q15 The experiment shown in the following figure was carried out to separate each ion from the aqueous solution containing metal ions Ag⁺, Cu²⁺, and Zn²⁺. From 1-6 in the table below, choose the correct combination of reagents for A and B in the figure. 15 Ag⁺, Cu²⁺, Zn²⁺ add A | | | | |---|---|---| | precipitate | filtrate | add B | | (compound of silver (Ag)) | ← | | | | | precipitate | | | | (compound of copper (Cu)) | | | | filtrate | | | | (containing Zn²⁺) | | A | B | | aqueous ammonia (in excess) | hydrogen sulfide | | aqueous ammonia (in excess) | dilute hydrochloric acid | | aqueous sodium hydroxide | hydrogen sulfide | | (small amount) | | | aqueous sodium hydroxide | dilute hydrochloric acid | | (small amount) | | | dilute hydrochloric acid | aqueous ammonia (in excess) | | dilute hydrochloric acid | hydrogen sulfide | ## Science - 37 ### Q16 The compound X, composed of carbon (C), hydrogen (H), and oxygen (O), is a white powder at normal temperature and pressure. When 3.0 mg of X was completely combusted, 4.4 mg of carbon dioxide and 1.8 mg of water were generated. From 1-5 below, choose the most appropriate one as X. 16 ① methanol (CH₄O) ② acetic acid (C₂H₄O₂) ③ fumaric acid (C₄H₄O₄) ④ glucose (C₆H₁₂O₆) ⑤ phthalic acid (C₈H₆O₄) ## Science - 38 ### Q17 How many isomers are possible for the compound the molecular formula of which is C₄H₈? From -6 below, choose the correct one. When stereoisomers are involved, each should be counted separately. 17 ① 4 ② 5 ③ 6 ④ 7 ⑤ 8 ⑥ 9 ## Science - 39 ### Q18 The following is the the reaction pathway diagram for compounds A-F, each of which is synthesized from the raw material, calcium carbide (CaC₂). From the following statements 1-6 on compounds A-F, choose the one which is not correct. 18 H₂O red-hot iron CaC₂ A conc. H₂SO₄ B C H₂O catalyst oxidation D unstable E F ① A has a C=C bond in the molecule. ② B is an aromatic compound. ③ C dissolves in water to show acidity. ④ D has hydroxy group(s). ⑤ E is identical with the compound obtained by the oxidization of methanol. ⑥ When sodium hydrogencarbonate is added to F, F dissolves to form a salt while a gas is generated. ## Science - 40 ### Q19 Three aromatic compounds X, Y, and Z gave the following experimental results a and b. a. When aqueous sodium hydrogencarbonate was added, X and Y reacted to generate a gas, but Z did not react. b. When aqueous iron(III) chloride was added, Y and Z reacted to form colored products, but X did not. X, Y, and Z are each one of A, B, or C. From -⑥ in the table below, choose the correct combination. 19 | | | | |---|---|---| | X | Y | Z | | A | B | C | | A | C | B | | B | A | C | | B | C | A | | C | A | B | | C | B | A | ## Science - 41 ### Q20 In the table below, polymers and their monomers are listed from a-f. Among these polymers, two are obtained by condensation polymerization. From - below, choose the correct combination. 20 | Polymer | Monomer(s) | |---|---| | a. acrylonitrile-butadiene rubber | CH₂=CH-CH=CH₂ CH₂=CH-CN | | b. nylon 6,6 | HOOC(CH₂)₄COOH H₂N(CH₂)₆NH₂ | | c. styrene-butadiene rubber | CH₂=CH-CH=CH₂ -CH=CH₂ | | d. nylon 6 | CH₂-CH₂-NH | | | CH₂ | | | CH₂-CH₂-CO | | e. poly(ethylene terephthalate) | HOOC COOH HO(CH₂)₂OH | | f. poly(vinyl acetate) | CH₂=CH | | | OCOCH₃ | ① a, d ② a, f ③ b, c ④ b, e ⑤ c, e ⑥ d, f End of Chemistry questions. Leave the answer spaces 21 - 75 blank. Please check once more that you have properly marked the name of your subject as "Chemistry" on your answer sheet. Do not take this question booklet out of the room.