chemical analysis

• What is the ideal purity of a compound in chemistry?

  100% pure
• How is purity defined in everyday language?

  As a substance with nothing added to it
• How is purity defined in chemistry?

  A substance containing only one compound or element
• What does a chemically pure substance do at a specific temperature?

  It melts or boils at a specific temperature
• How can you test the purity of a sample?

  By measuring its melting or boiling point
• What happens to the melting point when impurities are present?

  It lowers and increases the melting range
• What effect do impurities have on the boiling point of a substance?

  They increase the boiling point and range
• What are formulations in chemistry?

  • Mixtures with exact amounts of components
  • Made by following a formula (recipe)
  • Each component contributes to the formulation's properties
• What is an example of a formulation in paints?

  Pigment, solvent, binder, and additives
• Why are formulations important in the pharmaceutical industry?

  They ensure correct drug delivery and concentration
• Where can formulations be found in everyday life?

  In cleaning products, fuels, and cosmetics
• What information might you find on a product's packaging regarding formulations?

  The ratio or percentage of each component
• What are the two phases in chromatography?

  Mobile phase and stationary phase
• What is the role of the mobile phase in chromatography?

  It allows molecules to move
• What is the role of the stationary phase in chromatography?

  It prevents molecules from moving
• What happens during a chromatography experiment?

  Substances move between mobile and stationary phases
• How does the distribution of a chemical affect its movement in chromatography?

  It determines how far it moves in each phase
• What does a pure substance form in chromatography?

  One spot in any solvent
• What factors affect how far molecules move in chromatography?

  Solubility in solvent and attraction to paper
• What is an RF value in chromatography?

  Ratio of distance travelled by solute to solvent
• How is the RF value calculate?

  Distance travelled by substance divided by solvent
• What does a chromatogram represent?

  The result of chromatography analysis
• How can you confirm the presence of a substance in a mixture using chromatography?

  By matching RF values with a reference
• What happens to the RF value if the solvent changes?

  It will change for the substance
• What is the test for chlorine gas?

  Bleaches damp litmus paper white
• What happens to a glowing splint in oxygen?

  It reignites
• How can you test for carbon dioxide?

  By bubbling it through limewater
• What sound indicates the presence of hydrogen gas?

  A "squeaky pop"
• How can you test for carbonate ions?

  By adding dilute acid and limewater
• What indicates the presence of sulfate ions?

  A white precipitate of barium sulfate
• How do you test for halide ions?

  With nitric acid and silver nitrate
• What color flame indicates lithium ions?

  Crimson flame
• What color flame indicates sodium ions?

  Yellow flame
• What color flame indicates potassium ions?

  Lilac flame
• What color flame indicates calcium ions?

  Orange-red flame
• What color flame indicates copper ions?

  Green flame
• What is the purpose of flame emission spectroscopy?

  To identify metal ions and their concentrations
• How does flame emission spectroscopy work?

  It detects light emitted by excited electrons
• What does the intensity of a spectrum indicate in flame emission spectroscopy?

  The concentration of the ion in solution
• How can flame emission spectroscopy be used for mixtures?

  By comparing spectra against reference spectra