8.1 Purity, formulations, and chromatography

• Purity in chemistry refers to the degree to which a substance contains only one chemical compound
• Pure substances have distinct, sharp melting and boiling points, while mixtures have a range.


  True
• Examples of formulations include pharmaceutical drugs, detergents, and paints
• Pure substances have sharp, distinct melting and boiling points.
• What is the principle behind chromatography for measuring purity?

  Separates mixture components
• Using multiple methods provides a more comprehensive understanding of purity.


  True
• Steps in formulating mixtures and solutions:

  1️⃣ Define the desired properties

  2️⃣ Select components

  3️⃣ Determine proportions

  4️⃣ Mix components

  5️⃣ Test and adjust
• The final step in formulating mixtures is to test and adjust the formulation.
• Proper storage conditions are essential for the stability of formulations.


  True
• Match the concept with its definition:

  Purity ↔️ Substance contains only one chemical compound without impurities

  Formulations ↔️ Mixtures of substances combined for specific properties
• Arrange the following methods for measuring purity from simplest to most complex:

  1️⃣ Melting/Boiling Point Analysis

  2️⃣ Thin Layer Chromatography (TLC)

  3️⃣ High Performance Liquid Chromatography (HPLC)
• What type of melting and boiling points do pure substances have?

  Sharp, distinct
• What analytical technique separates components of a mixture?

  Chromatography
• High Performance Liquid Chromatography (HPLC) is used to quantify purity in a mixture.
• Steps in formulating mixtures and solutions

  1️⃣ Define the desired properties

  2️⃣ Select components

  3️⃣ Determine proportions

  4️⃣ Mix components

  5️⃣ Test and adjust
• What is the principle of paper chromatography?

  Capillary action
• What stationary phase is used in Thin Layer Chromatography (TLC)?

  Silica or alumina
• Chromatography separates components based on their differing affinities for a stationary and a mobile phase.
• What type of chromatography is used to analyze volatile components in fragrances?

  Gas Chromatography
• What are formulations created to achieve?

  Specific desired properties
• Match the method with its principle:

  Melting/Boiling Point Analysis ↔️ Sharp melting/boiling points

  Chromatography ↔️ Separation based on interaction with phases
• What type of melting and boiling points do pure substances have?

  Sharp and distinct
• High Performance Liquid Chromatography (HPLC) is used to quantify purity
• Calculating the ratios of components in a mixture involves chemical stoichiometry and mass balance
• What should be evaluated in a formulation to optimize its performance?

  Intended properties
• Chromatography separates mixtures based on their different affinities for a stationary and mobile phase.


  True
• Which type of chromatography uses adsorption onto a solid phase for separation?

  Thin Layer Chromatography (TLC)
• Components with stronger interactions with the stationary phase move faster in chromatography.

  False
• Pure substances consist of a single type of molecule
• What is the impact of high purity on a substance's properties and applications?

  Enhances effectiveness
• Match the key concept with its features:

  Purity ↔️ Single type of molecule/ion

  Formulations ↔️ Blend of multiple compounds
• Impurities broaden the melting and boiling point range of a substance.

  True
• Match the method with its principle:

  Melting/Boiling Point Analysis ↔️ Sharp, distinct melting/boiling points for pure substances

  Thin Layer Chromatography (TLC) ↔️ Separates components based on polarity

  High Performance Liquid Chromatography (HPLC) ↔️ Separates components based on interaction with a stationary phase
• When formulating mixtures, the first step is to define the desired properties
• What mixing techniques can ensure uniform distribution of components?

  Stirring, homogenization
• The key feature of purity is that pure substances have distinct melting and boiling points.
• What happens to the melting and boiling point range of a substance when impurities are present?

  Broadens
• Chromatography is a quantitative method for measuring purity.

  True
• Impurities in a substance broaden the melting and boiling point range.


  True
• Thin Layer Chromatography (TLC) can identify impurities in a substance.

  True