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35問 • 8ヶ月前

Liane

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問題一覧

What is the main use of potentiometry in analytical chemistry?

To determine pH or ion concentrations using selective electrodes

Which component of the pH meter directly responds to hydrogen ion concentration?

The glass electrode bulb

What is the purpose of the reference electrode in a combination pH electrode?

To provide a stable reference potential

Why is the glass membrane electrode valued for pH measurement?

Stability, Wide pH range, Resistance to interference

Which solution should be used to store a pH electrode to prevent it from drying out?

pH storage solution

What maintenance task should be performed before each use of a pH meter?

Calibration with standard buffer solutions

What should you do if you see air bubbles in the electrode bulb or junction?

Gently tap the electrode to remove air bubbles

What is the typical replacement interval for pH electrodes, assuming proper maintenance?

Every 12-18 months

What kind of junction allows ionic contact between the reference electrode and the solution?

Porous frit junction

Which step is recommended for cleaning a pH electrode after each use?

Rinse with distilled water and use appropriate cleaning solutions for residues

Which measurement describes the standard potential of an electrochemical half-cell under standard conditions?

Half-Cell Potential (E)

What is the main function of a galvanic cell?

Converts chemical to electrical energy

In an electrolytic cell, what is true about the cell potential and the nature of the redox reaction?

E'cell < 0 and the redox reaction is non-spontaneous

Which unit is used to express the concentration of a specific ion or species in solution as listed in the measurements?

Molarity (M)

In the example of a Daniell cell, which metal acts as the anode and which acts as the cathode?

Zn acts as the anode and Cu acts as the cathode

What is the substance called that causes another substance to be oxidized in a redox reaction?

Oxidizing agent

Which of the following statements is true about oxidation and reduction?

Oxidation involves the loss of electrons., Reduction involves the gain of electrons.

According to the rules summarized, what is the oxidation number of oxygen in H2O2 (hydrogen peroxide)?

-1

In the reaction Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), which element is oxidized, and which is reduced?

Zn is oxidized; Cu²⁺ is reduced.

What is the sum of the oxidation numbers for all atoms in a neutral compound?

Which figure of merit in analytical chemistry describes the ability of a method to detect small amounts of analyte, often quantified as the slope of the calibration curve?

Sensitivity

What term describes the lowest concentration of analyte that can be detected by an analytical method?

Limit of Detection (LOD)

Which parameter is defined as the lowest concentration of analyte that can be quantified with accuracy and precision?

Limit of Quantification (LOQ)

What is used to quantify analytes by establishing a relationship between their concentration and instrument response, typically following y = mx + b?

Calibration Curve

Which figure of merit refers to the percentage of analyte recovered from a sample?

Recovery

Which of the following is NOT considered a measure of central tendency?

Standard deviation

What is a systematic (or determinate) error in chemical analysis?

An error that consistently deviates from the expected value in a specific direction

What does the range measure in a dataset?

The difference between the highest and lowest values

Which error type is most likely caused by using the wrong reagent or instrument?

Gross error

Which of the following statements about random (indeterminate) errors is TRUE?

They are always present and fluctuate randomly

Which term is defined as 'the specific substance or chemical component being measured or analyzed' in analytical chemistry?

Analyte

What is a 'blank' in the context of analytical chemistry?

A sample that does not contain the analyte, used to correct for background signals

What term describes a 'precisely measured portion of a larger sample, used to ensure consistency in analysis or to prepare replicates'?

Aliquot

What is the purpose of a 'standard' in analytical chemistry?

A solution with a known concentration of analyte, used for calibration

Which of the following best describes a 'protocol' in analytical chemistry?

A formal set of standardized guidelines, often established by a governing body, for conducting and documenting sample analysis

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問題一覧

What is the main use of potentiometry in analytical chemistry?

To determine pH or ion concentrations using selective electrodes

Which component of the pH meter directly responds to hydrogen ion concentration?

The glass electrode bulb

What is the purpose of the reference electrode in a combination pH electrode?

To provide a stable reference potential

Why is the glass membrane electrode valued for pH measurement?

Stability, Wide pH range, Resistance to interference

Which solution should be used to store a pH electrode to prevent it from drying out?

pH storage solution

What maintenance task should be performed before each use of a pH meter?

Calibration with standard buffer solutions

What should you do if you see air bubbles in the electrode bulb or junction?

Gently tap the electrode to remove air bubbles

What is the typical replacement interval for pH electrodes, assuming proper maintenance?

Every 12-18 months

What kind of junction allows ionic contact between the reference electrode and the solution?

Porous frit junction

Which step is recommended for cleaning a pH electrode after each use?

Rinse with distilled water and use appropriate cleaning solutions for residues

Which measurement describes the standard potential of an electrochemical half-cell under standard conditions?

Half-Cell Potential (E)

What is the main function of a galvanic cell?

Converts chemical to electrical energy

In an electrolytic cell, what is true about the cell potential and the nature of the redox reaction?

E'cell < 0 and the redox reaction is non-spontaneous

Which unit is used to express the concentration of a specific ion or species in solution as listed in the measurements?

Molarity (M)

In the example of a Daniell cell, which metal acts as the anode and which acts as the cathode?

Zn acts as the anode and Cu acts as the cathode

What is the substance called that causes another substance to be oxidized in a redox reaction?

Oxidizing agent

Which of the following statements is true about oxidation and reduction?

Oxidation involves the loss of electrons., Reduction involves the gain of electrons.

According to the rules summarized, what is the oxidation number of oxygen in H2O2 (hydrogen peroxide)?

-1

In the reaction Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), which element is oxidized, and which is reduced?

Zn is oxidized; Cu²⁺ is reduced.

What is the sum of the oxidation numbers for all atoms in a neutral compound?

Which figure of merit in analytical chemistry describes the ability of a method to detect small amounts of analyte, often quantified as the slope of the calibration curve?

Sensitivity

What term describes the lowest concentration of analyte that can be detected by an analytical method?

Limit of Detection (LOD)

Which parameter is defined as the lowest concentration of analyte that can be quantified with accuracy and precision?

Limit of Quantification (LOQ)

What is used to quantify analytes by establishing a relationship between their concentration and instrument response, typically following y = mx + b?

Calibration Curve

Which figure of merit refers to the percentage of analyte recovered from a sample?

Recovery

Which of the following is NOT considered a measure of central tendency?

Standard deviation

What is a systematic (or determinate) error in chemical analysis?

An error that consistently deviates from the expected value in a specific direction

What does the range measure in a dataset?

The difference between the highest and lowest values

Which error type is most likely caused by using the wrong reagent or instrument?

Gross error

Which of the following statements about random (indeterminate) errors is TRUE?

They are always present and fluctuate randomly

Which term is defined as 'the specific substance or chemical component being measured or analyzed' in analytical chemistry?

Analyte

What is a 'blank' in the context of analytical chemistry?

A sample that does not contain the analyte, used to correct for background signals

What term describes a 'precisely measured portion of a larger sample, used to ensure consistency in analysis or to prepare replicates'?

Aliquot

What is the purpose of a 'standard' in analytical chemistry?

A solution with a known concentration of analyte, used for calibration

Which of the following best describes a 'protocol' in analytical chemistry?

A formal set of standardized guidelines, often established by a governing body, for conducting and documenting sample analysis