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• What is solubility?

  It describes how well certain solutes can dissolve in certain solvents.
• Why does sodium chloride dissolve well in water?

  Because it disassociates into sodium cations and chloride anions, which are attracted to water molecules.
• What is the molecular structure of water when nothing is dissolved in it?

  It consists of one oxygen atom attached to two hydrogen atoms.
• What is the significance of the partial charges in water molecules?

  The oxygen end is partially negative, while the hydrogen ends are partially positive, allowing for hydrogen bonding.
• What are hydrogen bonds?

  They are attractions between the partially negative end of one water molecule and the partially positive end of another water molecule.
• Why do sodium cations and chloride anions dissolve well in water?

  Their attraction to water molecules is stronger than the attraction between the ions themselves.
• What happens to water molecules when sodium chloride is added?

  Water molecules surround the ions, preventing them from clustering together.
• What are dispersion forces?

  They are weak forces that attract molecules to each other.
• What happens when pentane is mixed with hexane?

  They dissolve because they are roughly as attracted to each other as they are to themselves.
• What occurs when hexane is mixed with water?

  Hexane does not dissolve well in water because water is more attracted to itself than to hexane.
• What is an example of an organic molecule that dissolves well in water?

  Ethanol.
• Why does ethanol dissolve well in water?

  Because it has a polar OH group that attracts water molecules.
• What happens to the solubility of alcohols as the carbon chain length increases?

  It becomes harder for them to dissolve in polar solvents like water.
• What is the principle of "like dissolves like" in chemistry?

  • Polar solvents dissolve polar solutes.
  • Nonpolar solvents dissolve nonpolar solutes.
  • The attraction between solute and solvent must be strong enough for dissolution.
• What are the two types of chromatography discussed in the lesson?

  Paper chromatography and thin layer chromatography
• What is chromatography primarily used for in forensic science?

  It is used as a separation technique.
• What is the process of creating a chromatogram using food coloring?

  1. Draw a pencil line at the bottom of chromatography paper.
  2. Dab spots of red, green, and blue food coloring on the line.
  3. Place the paper in a beaker with water, ensuring the water does not touch the spots.
  4. As water is absorbed, it separates the food coloring components.
• What is the stationary phase in chromatography?

  The chromatography paper is the stationary phase.
• What is the mobile phase in chromatography?

  The water is the mobile phase.
• How does solubility affect the distance traveled by components in chromatography?

  A more soluble component travels a greater distance, while a less soluble component travels a shorter distance.
• What does the retention factor (RF) value measure in chromatography?

  It measures the distance a separated component has traveled compared to the distance the solvent has traveled.
• What does a larger retention factor value indicate about a component's solubility?

  A larger retention factor value means the component is more soluble in the solvent.
• What is the purpose of ninhydrin in thin layer chromatography?

  Ninhydrin is used to detect fingerprints and can turn some components purple.
• What are some applications of chromatography in forensic science?

  • Identifying drugs
  • Comparing inks
  • Analyzing lipsticks
  • Examining saliva
  • Investigating explosives
• How do paper chromatography and thin layer chromatography differ in their stationary phase?

  • Paper chromatography uses chromatography paper as the stationary phase.
  • Thin layer chromatography uses a glass plate with a thin layer of silica gel or absorbent material as the stationary phase.
• What happens to colorless components in thin layer chromatography?

  They may be detected by spraying with ninhydrin or viewed under UV light.
• What is the conclusion regarding the use of paper and thin layer chromatography?

  • Both methods separate components of a mixture based on solubility.
  • The relative solubility can be determined by calculating retention factor values.
  • More soluble components have larger retention factor values, while less soluble components have smaller values.