所屬科目:研究所、轉學考(插大)-分析化學
1. What volume of a 36% HCl solution must be diluted to prepare 1.000 L of a 0.1000 M HClsolution? The density of 36% HCl is 1.18 g/mL. (The molecular mass of HCl is 36.45 g/mol.)(A) 11.7 mL (B) 8.6 mL (C) 1.2 mL (D) 10.1 mL (E) 64.6 mL
2. Which of the statements below are TRUE regarding the mean and standard deviation?I As the number of measurements increases, ?̅ approaches if there is no randomerror.II The square of the standard deviation is the average deviation.III The mean is the center of the Gaussian distribution.IV The standard deviation measures the width of the Gaussian distribution.(A) II, III, and IV (B) I, III, and IV (C) I and II (D) I, II, and IV (E) III and IV
3. Any one of the mass spectrometers needs several essential components. They areI ion source II decelerator III detector IV mass separator Vaccelerator(A) I and IV (B) I, IV, and V (C) I, III, and IV (D) II, III, and IV (E) I, III,IV, and V
4. Which of the following statement is INCORRECT for gas chromatography detectors?(A) Thermal conductivity detectors respond to the thermal conductivity difference betweenanalyte and carrier gas.(B) Thermal conductivity detectors respond to all analytes.(C) Flame ionization detectors generate signal by burning the analyte, generating electrons.(D) For thermal conductivity and flame ionization detectors, detector response isproportional to analyte concentration.(E) Flame ionization detectors are used only with inorganic compounds.
5. As particle size of packing material in a column decreases for HPLC, the required solventpressure , the plate number , and the resolution?(A) increases; increases; decreases (B) decreases; increases; increases(C) increases; decreases; decreases (D) increases; increases; increases(E) decreases; decreases; decreases
6. A set of five solutions are prepared by delivering 10 mL of unknown sample and increasingvolumes of standard (0, 5, 10, 15, and 20 mL) into 50-mL volumetric flasks. Reagents arethen added and diluted to volume. A plot of signals versus the final concentrations ofstandards is constructed. The x-intercept is −3.90 mM. What is the concentration of theunknown sample?(A) 0.39 mM (B) 3.9 mM (C) 19.5 mM (D) 39 mM (E) 195 mM
7. A Na2CO3standard solution is prepared by transferring4.9634 grams of primary standard-grade sodium carbonate to a 500.0-mL volumetric flask, dissolving the sample in ~100 mLof distilled deionized water and diluted to the mark. A 50.00-mL aliquot is taken and titratedwith 85.30 mL of HCl solution. Calculate the concentration of the HCl solution. (Themolecular mass of Na2CO3 is 105.99 g/mol.)(A) 0.0549 M (B) 0.1098 M (C) 0.1598 M (D) 0.1997 M (E) 0.3196 M