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Questions and Answers
What is the unit of Molarity?
What is the unit of Molarity?
1 M HCl solution contains 36.5 grams of HCl per liter of solution.
1 M HCl solution contains 36.5 grams of HCl per liter of solution.
True
What is the formula for calculating the number of equivalents of solute in normality?
What is the formula for calculating the number of equivalents of solute in normality?
N = Equivalents / VL
The equivalent weight of a diprotic acid is calculated as Eq.wt = Mwt / ______.
The equivalent weight of a diprotic acid is calculated as Eq.wt = Mwt / ______.
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Match the following substances with their equivalent weight for one liter of solution:
Match the following substances with their equivalent weight for one liter of solution:
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How can normality be expressed in relation to molarity?
How can normality be expressed in relation to molarity?
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A strong monoprotic acid has an equivalent weight equal to its molecular weight.
A strong monoprotic acid has an equivalent weight equal to its molecular weight.
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What is the purpose of calculating equivalent weight (Eq.wt)?
What is the purpose of calculating equivalent weight (Eq.wt)?
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What is the weight/volume percentage for 10 g of AgNO3 in 100 mL of solution?
What is the weight/volume percentage for 10 g of AgNO3 in 100 mL of solution?
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1 ppm is equivalent to 1 mg/L.
1 ppm is equivalent to 1 mg/L.
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What is the molar ratio (R) when titrating H₂SO₄ with NaOH?
What is the molar ratio (R) when titrating H₂SO₄ with NaOH?
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The concentration of a solution is expressed as __ g of solute in 100 g of solution when using weight/weight percentage.
The concentration of a solution is expressed as __ g of solute in 100 g of solution when using weight/weight percentage.
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Match the concentration expressions with their formulas:
Match the concentration expressions with their formulas:
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What is the equivalent weight of H₂SO₄ in grams?
What is the equivalent weight of H₂SO₄ in grams?
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The equation N.VmL for the sample equals N.VmL for the titrant at the equivalence point.
The equation N.VmL for the sample equals N.VmL for the titrant at the equivalence point.
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How many mg are there in 1 ppm?
How many mg are there in 1 ppm?
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What does qualitative analysis determine?
What does qualitative analysis determine?
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The equivalence point in titration is the same as the end point.
The equivalence point in titration is the same as the end point.
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What is the role of an indicator in volumetric analysis?
What is the role of an indicator in volumetric analysis?
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The _____ is the standard solution added from the burette during titration.
The _____ is the standard solution added from the burette during titration.
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Match the following indicators to their color changes in different pH environments:
Match the following indicators to their color changes in different pH environments:
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Which of the following is NOT a characteristic of an ideal standard solution for titration?
Which of the following is NOT a characteristic of an ideal standard solution for titration?
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The end point of a titration can be calculated exactly.
The end point of a titration can be calculated exactly.
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What is the process called that involves the slow addition of titrant from the burette to the sample solution?
What is the process called that involves the slow addition of titrant from the burette to the sample solution?
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Which of the following is NOT a characteristic of a primary standard substance?
Which of the following is NOT a characteristic of a primary standard substance?
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Sodium hydroxide is considered a primary standard solution.
Sodium hydroxide is considered a primary standard solution.
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What is the primary method of standardizing a secondary standard solution?
What is the primary method of standardizing a secondary standard solution?
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The balanced chemical equation is essential for _____ during volumetric analysis.
The balanced chemical equation is essential for _____ during volumetric analysis.
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Match the following acids to their classification as primary standards:
Match the following acids to their classification as primary standards:
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Which of the following must be true at the equivalence point during a titration?
Which of the following must be true at the equivalence point during a titration?
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Secondary standard solutions can have their concentrations calculated from the weight of the solute and the volume of the solution.
Secondary standard solutions can have their concentrations calculated from the weight of the solute and the volume of the solution.
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Name one example of a primary standard used as a reducing agent.
Name one example of a primary standard used as a reducing agent.
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Study Notes
PCC/PCD 101: Pharm. Analytical Chemistry I - Lecture Week 4
- Analytical Chemistry: Divided into quantitative and qualitative analysis
- Quantitative Analysis: Determines the concentration (amount) of a substance in a sample. Examples include volumetric analysis (titrimetry).
- Qualitative Analysis: Determines the identity (type) of a substance in a sample. Examples include identifying cations and anions.
- Volumetric Analysis (Titrimetry): A type of quantitative analysis. Titrant (standard solution with known concentration) is added to analyte (sample with unknown concentration) until the equivalence point is reached. The addition of titrant is controlled using a burette, and the reaction takes place in a conical flask.
- Titration: A process of slow and controlled addition of titrant into the sample until a complete reaction occurs
- Equivalence Point: The theoretical point in titration where the amount of titrant is chemically equivalent to the amount of sample.
- End Point: A practical point observed in titration using an indicator. The point where an observable physical change occurs , usually near the equivalence point, indicating the completion of the reaction.
- Titration Error: Difference between the end point and equivalence point.
- Indicator: A substance added to the analyte to make the end point easily observable. Indicators change color at or near the equivalence point.
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Typical Indicator Changes: Indicators may change in color(or appearance of turbidity)
- Examples: Phenolpthalein, Methyl Orange
- Standard Solutions: Solutions with precisely known concentrations used for titrations. They are classified as primary or secondary.
- Primary Standard Solution: Prepared by dissolving a known amount of a primary standard substance in a measured volume of water. Concentration does not change over time (e.g., Benzoic acid, Potassium Acid Phthalate).
- Characteristics of Primary Standard Substances: Must be very pure, stable, High molecular weight, easily available, soluble in titration medium
-
Secondary Standard Solution: Solutions whose concentrations cannot be calculated directly from the weight. Their concentrations must regularly determined via process called standardization. Standardization can be done by titration with a primary standard or another standardized secondary standard solution (eg: HCl, NaOH)
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Characteristics of ideal standard solutions for titration:
- Concentration must be stable over long time
- Reaction with analyte must be rapid
- Undergo selective simple reaction
- Demonstrated with a simple balanced chemical equation
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Characteristics of ideal standard solutions for titration:
-
Requirements for Reactions in Volumetric Analysis:
- Simple single reaction with balanced chemical equation
- Complete and quantitative reaction between analyte and titrant
- Be rapid to allow sharp end points
- Have suitable method for end point detection
- Molar Concentration (Molarity): Number of moles of solute in one liter of solution. M = moles/volume (L).
- Calculating Molarity: M = wt/M.wt (gram) x (1/Volume(L)).
- Preparation of 1 Molar solution: Dissolves one mole (MWt) of a substance in 1L of water
- Normal Concentration (Normality): Number of equivalents of solute in one liter of solution. N = equivalents/volume(L).
- Equivalent Weight (Eq.wt): Molar weight divided by the number of H+ released/consumed in the reaction. Eq. wt. = M. wt / n where n = number of H+, it differs based on reaction type.
- Preparation of 1 Normal (1N) solution: Dissolves 1 equivalent weight of a substance in 1L of water
- Percent Concentration: A way to express concentration in terms of percentage: weight/weight, volume/volume, weight/volume e.g., 10% AgNO3 = 10g AgNO3 in 100mL solution.
- Parts per Million (ppm): Used for very low concentrations, 1 ppm = 1 mg/L = 1µg/mL = 1 ng/µL.
- Dilution Process: C₁V₁ = C₂V₂ (Concentration before dilution x Volume before dilution = Concentration after dilution x Volume after dilution).
- Important Conversions between different concentration units.
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Description
This quiz covers key concepts from Week 4 of Pharm. Analytical Chemistry I. Focus areas include qualitative and quantitative analysis, volumetric analysis, and the process of titration. Test your understanding of the fundamental techniques and principles used in analytical chemistry.
