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(PTs and QSets) Bridging to Anachem
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1
Question
Which 1.00 g sample of an element contains the greatest number of molecules? A. Buckminsterfullerene (C60) B. Ozone (O3) C. White phosphorus (P4) D. Sulfur (S8)
Answer
B. Ozone (O3)
2
Question
In liquid-liquid extraction, it is often necessary to identify the aqueous and organic layers. To test the layers, a drop of water can be added to the top layer. If the drop of water dissolves in the top layer, then the top layer is: A. Organic B. Aqueous C. Denser D. Nonaqueous
Answer
B. Aqueous
3
Question
A sample of gas occupies 4.0 L at a pressure of 2.0 atm. If the pressure is decreased to 1.0 atm at constant temperature, what will be the new volume of the gas? A. 1L B. 2L C. 4L D. 8L
Answer
D. 8L
4
Question
This atomic model depicts atoms as small, positively charged nuclei surrounded by electrons in circular orbits. A. Bohr's model B. Dalton's model C. Thomson's model D. Rutherford's model
Answer
A. Bohr's model
5
Question
In a blood sample being tested for glucose, which term describes all components except glucose? A. Blank B. Matrix C. Standard D. Reagent
Answer
B. Matrix
6
Question
Which functional group typically shows a strong, broad absorption around 3200-3600 cm-1 in an IR spectrum? A. Carbonyl (C=O) B. Hydroxyl (O–H) C. C-H (alkane) D. Nitrile (C=N)
Answer
B. Hydroxyl (O–H)
7
Question
Which of the following best differentiates a tertiary method from primary and secondary methods? A. It uses a highly purified chemical to generate a standard solution. B. It provides the most accurate results and is used to certify reference materials. C. It is based on simple tools or kits that are often pre-calibrated and designed for rapid field use. D. It relies on a calibration curve derived from known standards.
Answer
C. It is based on simple tools or kits that are often pre-calibrated and designed for rapid field use.
8
Question
All of the following statements are true, except: A. Two different pure substances have identical melting points. B. An impure sample of a substance has a wider melting point range. C. Melting point serves as an indicator of the purity of a solid crystalline substance. D. Every pure solid crystalline substance has a characteristic and unique melting point.
Answer
A. Two different pure substances have identical melting points.
9
Question
A chemist has isolated a solid carboxylic acid of unknown formula from a medicinal herb. Which experiment will be most useful in assessing the purity of the isolated material? A. Melting point B. Titration with NaOH C. Combustion analysis D. UV-Visible spectrophotometry
Answer
A. Melting point
10
Question
The dynamic range in analytical measurement refers to the range over which A. the detection limit is reached B. the instrument output remains unchanged C. the instrument shows the greatest sensitivity D. the instrument response is linear with the analyte concentration
Answer
D. the instrument response is linear with the analyte concentration
11
Question
In paper chromatography, what does a higher Rf value indicate?
Answer
The compound is less polar
12
Question
What is the name of BF3? A. Boron trifluoride B. Bromine fluoride C. Beryllium fluoride D. Triflouride bromide
Answer
A. Boron trifluoride
13
Question
A student is tasked to measure 12 mL of a liquid as precisely as possible. Which measuring device should be selected for this task? A. 25 mL beaker B. 25 mL graduated cylinder C. 25 mL conical flask D. 25 mL volumetric flask
Answer
B. 25 mL graduated cylinder
14
Question
Which molecule has a dipole moment of zero? A. CO B. CO2 C. CH3ОН D. CH3CООН
Answer
B. CO2
15
Question
Which spectrum gives information about the connectivity of atoms in a molecule?
Answer
NMR spectrum
16
Question
Which of the following is used to remove trace amounts of water from organic solutions and can be added to the pooled organic layers before the removal of the organic solvent? A. Drying agent B. Boiling stone C. Seed crystal D. None of the above
Answer
A. Drying agent
17
Question
Examine the graduated cylinders shown. What are the correct volumes of the liquids in each? A. 6.60 mL and 2.00 mL B. 6.60 mL and 2.30 mL C. 6.70 mL and 2.00 mL D. 6.70 mL and 2.30 mL
Answer
B. 6.60 mL and 2.30 mL
18
Question
Which of the following statements about proper weighing techniques is correct? A. Chemicals should be placed directly on the balance pan to ensure accurate mass readings. B. The tare function is used to subtract the chemical's mass from the total mass of the container. C. Weighing by difference is recommended for hygroscopic substances to prevent moisture absorption. D. Weighing dishes and paper are never used because they affect the accuracy of the balance.
Answer
C. Weighing by difference is recommended for hygroscopic substances to prevent moisture absorption.
19
Question
What is the most likely consequence of heating a liquid during distillation without the use of boiling chips? A. The liquid will boil at a lower temperature than expected due to reduced vapor pressure. B. The liquid will evaporate too quickly, causing excessive loss of material. C. The liquid may undergo "bumping," leading to sudden, violent boiling, which can cause spillage and loss of sample. D. The distillation rate will be significantly slower, as boiling chips increase the temperature.
Answer
C. The liquid may undergo "bumping," leading to sudden, violent boiling, which can cause spillage and loss of sample.
20
Question
A student uses Beer's Law to determine the concentration of a colored salt solution by measuring its absorbance at the salt's maximum absorbance wavelength (Λmax). Which of the following would most likely cause the calculated concentration to be higher than the actual concentration? A. The cuvette is not rinsed with the salt solution after washing. B. The cuvette is not wiped clean before being placed in the spectrophotometer. C. Less than the recommended volume of salt solution is added to the cuvette. D. The spectrophotometer is set to a wavelength other than λmax.
Answer
B. The cuvette is not wiped clean before being placed in the spectrophotometer.
21
Question
What type of intermolecular force must be overcome when hexane (C6H14) is vaporized? A. Hydrogen bonding B. Covalent bonding between carbons C. Dipole-dipole interactions D. London dispersion forces
Answer
D. London dispersion forces
22
Question
Which factor primarily affects retention time in gas chromatography?
Answer
Boiling point of the compound
23
Question
Which type of crucible offers the highest maximum temperature resistance and is suitable for high-temperature applications? A. Zirconia B. Platinum C. Porcelain D. Pyrex glass
Answer
A. Zirconia
24
Question
What common property do elements in the same group of the periodic table typically share? A. Same atomic number B. Same number of valence electrons C. Same number of electron shells D. Same atomic mass
Answer
B. Same number of valence electrons
25
Question
What is the arrangement of Li, Na, K, and Rb in increasing ionization energy? A. Rb < K < Na < Li B. Li < Na < K < Rb C. Li < Rb < Na <K D. K> Rb > Li > Na
Answer
A. Rb < K < Na < Li
26
Question
What is the pressure of hydrogen gas if 0.412 mol occupies a volume of 3.25 L at 16°C? A. 1 atm B. 2 atm C. 3 atm D. 4 atm
Answer
C. 3 atm
27
Question
Which of the following is a chemical equation? A. CO2 B. CH4 + О2 → СO2 + H2O C. Ice + Heat → Water D. Iron + Oxygen Rust
Answer
B. CH4 + О2 → СO2 + H2O
28
Question
Which apparatus would be most suitable for collecting a sample of solid barium sulfate produced through the reaction of aqueous solutions of barium hydroxide and sulfuric acid? A. Barometer B. Beaker C. Büchner funnel D. Burette
Answer
C. Büchner funnel
29
Question
All of the following are physical changes except: A. Grating a block of cheese B. Crushing ice cubes to make ice chips C. Straightening a bent piece of iron with a hammer D. Heating a blue powdered material to produce a white glassy substance
Answer
D. Heating a blue powdered material to produce a white glassy substance
30
Question
A standard HCl solution is titrated to a pink phenolphthalein endpoint by adding a NaOH solution while stirring. If a solution becomes pink throughout but loses its color upon standing for a short time, what should be done to restore the color? A. Add more phenolphthalein indicator. B. Add an additional drop of NaOH solution. C. Add an additional drop of HCI solution. D. Stir more vigorously.
Answer
B. Add an additional drop of NaOH solution.