1 [Single-choice question]
In order to obtain a crystal precipitate that is pure and easy to filter and wash, it is required
A. The aggregation speed during precipitation is small and the orientation speed is large
B. The aggregation speed during precipitation is large and the orientation speed is small
C, the degree of supersaturation of the solution is greater
D. The solubility of the precipitate should be small
Your answer: A
Reference answer: A
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2 [Single-choice question]
The molecular formula of an alkane is, and there are only two dichloro derivatives, then its structure is
A. n-pentane
B. Isopentane
C. Neopentane
D. This substance does not exist
Your answer: C
Reference answer: C
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3 [Single-choice question]
Which of the following conditions is not the precipitation condition required for crystal precipitation
A. Precipitation should be carried out in a concentrated solution
B. Precipitating agent should be added under constant stirring
C. Precipitation should be carried out in hot solution
D. Precipitation should be aged
Your answer: A
Reference answer: A
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4 [Single-choice question] The difference between differential spectrophotometry and ordinary spectrophotometry lies in the difference in the reference solution. The reference solution of the former is
A. Distilled water
B. Solvent
C. Deionized water
D. A standard solution with a slightly lower concentration than the test solution
E. A standard solution slightly higher than the test solution
Your answer: D
Reference answer: D
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5 [Single-choice question] Under certain temperature conditions, the electrode potential of the reference electrode and the electrode potential of the indicator electrode in the working battery feature is
A. The electrode potential of the reference electrode is basically unchanged, while the electrode potential of the indicator electrode changes with the activity of the ion to be measured.
B. The electrode potential of the indicator electrode is basically unchanged, while the electrode potential of the reference electrode changes with the activity of the ion to be measured.
C. The electrode potentials of the two are basically unchanged.
Your answer: A
Reference answer: A
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6 [Single-choice question] The premise of reliable analysis results can be judged from good precision is
A. The system error is small
B. Increase the number of parallel measurements
C. The random error is small
D. The relative standard deviation is small
Your answer: A
Reference answer: A
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7 [Single-choice question] What is the time to add starch indicator by indirect iodometric method
A. Before the titration starts
B. When the titration is close to the end point
C. Titrate to halfway
D. The color of titrated iodine fades
Your answer: B
Refer to the answer: B
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8 [Single-choice question]
Which of the following situations in the titration analysis and determination will lead to systematic errors?
A. The reading of the burette is wrong
B. Droplets splash out during titration
C. The weight is not corrected
D. The sample has not been fully mixed
Your answer: C
Reference answer: C
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9 [Single-choice question] Analytical chemistry basis The purpose and task of analysis can be divided into
A. Qualitative analysis, quantitative analysis, structural analysis
B. Constant analysis, semi-micro analysis, micro analysis
C. Inorganic analysis, organic analysis
D. Chemical analysis, instrumental analysis
Your answer: A
Reference answer: A
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10 [Single-choice question] Which of the following compounds is the most acidic
A. Fluoroacetic acid
B. Chloroacetic acid
C. Bromoacetic acid
D. Iodoacetic acid
Your answer: A
Reference answer: A
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11 [Single-choice question] Which of the following instruments does not need to be rinsed three times with the solution contained in it?
A. Burette
B. volumetric flask
C. Pipette
D. Reagent bottle
Your answer: B
Reference answer: B
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12 [Single-choice question] You can use the following methods to reduce large accidental errors in analysis and testing
A. Conduct a control laboratory
B. Conduct a blank laboratory
C. Perform instrument calibration
D. Correct the analysis results
E. Increase the number of parallel experiments
Your answer: E
Reference answer: E
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13 [Single-choice question] When comparing titration, use NaOH standard solution to titrate HCl. Make the concentration of HCl solution
A. No effect
B. On the low side
C. High
D. It may be high or low
Your answer: C
Reference answer: C
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14 [Single-choice question] The relationship between the conjugate acid-base pair Ka and Kb is
A、Ka=Kb
B、Ka×Kb=1
C、Ka×Kb=1Kw
D. Ka÷Kb=1
Your answer: C
Reference answer: C
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15 [Single-choice question] The carbon in the following compounds is SP hybridized
A. Ethane
B. Vinyl
C. Acetylene
D. Benzene
Your answer: C
Reference answer: C
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16 [Single-choice question] What is the precipitation condition for crystal precipitation?
A, thick, cold, slow, stir, Chen
B. Thin, hot, fast, stir, old
C, dilute, heat, slow, stir, aged
D. Thin, cold, slow, agitated, old
Your answer: C
Reference answer: C
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17 [Single-choice question] Which of the following compounds is easiest to carry out nitration reaction
A. Benzene
B. Nitrobenzene
C. Toluene
D. Chlorobenzene
Your answer: C
Reference answer: C
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18 [Single-choice question] The result calculated by the calculator (2.236×1.1124)/(1.036×0.2000) is 12.004471, and the result should be corrected according to the effective number operation rules about
A、12.0045
B、12.0
C、12.00
D. 12.004
Your answer: C
Reference answer: C
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19 [Single-choice question] () affects the solubility of the precipitate
A. Surface adsorption
B. Co-precipitation
C. Salt effect
D. Post-precipitation
Your answer: C
Reference answer: C
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20 [Single-choice question] Blank test in chemical qualitative analysis, which of the following is correct
A. Check reagents
B. Check test equipment and instruments
C. Check the test method
D. Check the operation process
Your answer: A
Reference answer: A
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21 [Single-choice question]
What are the factors of the molar absorptivity of the complex
A. The thickness of the cuvette
B. The wavelength of the incident light
C, the concentration of colored matter
D. The compound
Your answer: B
Reference answer: B
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22 [Single-choice question] What is the correct operation method for titration with a basic burette
A. Pinch the left hand slightly below the glass bead
B. Pinch the right hand slightly below the glass bead
C. Pinch the left hand slightly higher than the glass bead
D. Pinch your right hand slightly higher than the glass beads
Your answer: C
Reference answer: C
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23 [Single-choice question] It is used when the reaction speed is slow or the reactant is solid, and cannot be quantified immediately after adding the titrant or there is no The titration reaction of the appropriate indicator, the commonly used titration method is
A. Direct titration
B. Back titration
C. Displacement titration
D. Indirect titration
Your answer: B
Reference answer: B
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24 [Single-choice question] For a colored solution that conforms to the Lambert-Beer law, when the concentration changes
A, the maximum absorption wavelength changes, the absorbance remains the same
B. The absorbance changes, but the transmittance remains the same
C. The maximum absorption wavelength remains the same, but the absorbance changes
D. Both the maximum absorption wavelength and the absorbance change
Your answer: C
Reference answer: C
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25 [Single-choice question] What is the correct way to use the starch indicator in the indirect iodometric method
A. Add indicator at the beginning of titration
B. In order to make the indicator sensitive to color change, it should be properly heated
C. The indicator must be added at the end point
D. The indicator must be added near the end point
Your answer: D
Reference answer: D
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26 [Single-choice question]
It is generally considered that the sewage is suitable for biochemical treatment, and its value should be greater than
A、0.1
B、0.2
C、0.3
D. 0.4
Your answer: C
Reference answer: C
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27 [Single-choice question] When the zero point of the electronic balance deviates greatly, which part should be adjusted
A. Balance level
B. Return to zero button
C. Increment button
D. Peeling button
Your answer: B
Reference answer: B
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28 [Single-choice question] Regarding the acid effect of EDTA, which of the following statements is correct
A. The smaller the acid effect coefficient, the lower the stability of the complex
B. The smaller the pH value, the larger the acid effect coefficient
C. The larger the acid effect coefficient, the larger the PM jump range of the coordination titration curve
D. The acid effect curve represents the highest pH value that can be accurately titrated by each metal ion.
Your answer: B
Reference answer: B
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. If the absolute error of the sample is 0.0002g, generally at least weigh the sample
A、0.1g
B、0.2g
C、0.3g
D. 0.4g
Your answer: B
Reference answer: B
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30 [Single-choice question] When choosing an acid-base indicator, which of the following factors does not need to be considered
A. The pH at the stoichiometric point
B. Range of indicator color change
C. The amount of the indicator substance
D. Titration direction
Your answer: C
Reference answer: C
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There are 5 sub-questions in total, 2 points for each sub-question, 10 points in total.
31 [Judgment question] The solution that does not develop color to the phenolphthalein indicator should not be an acidic solution.
correct
Wrong
Your answer: Wrong
Reference answer: Wrong
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32 [True or False Question] Two strong electrolyte solutions with pH=2 and pH=4, the pH=3 after equal volume mixing.
correct
Wrong
Your answer: Wrong
Reference answer: Wrong
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33 [True or False Question] At a certain temperature, if the pH value of the solution is changed, the ion product of water remains unchanged.
correct
Wrong
Your answer: Correct
Reference answer: Correct
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34 [False and False Questions] Under certain conditions, the precipitation reaction can be absolutely complete.
correct
False
Your answer: False
Reference answer: False
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35 [False and False Questions] The same ion effect can greatly reduce the solubility of insoluble strong electrolytes.
correct
Wrong
Your answer: Correct
Reference answer: Correct
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