science

• What is chromatography used for?


  To separate mixtures of soluble liquids
• What is a solute?

  The solid added to a solution
• What is distillation?

  A method to separate soluble and solvent
• How does evaporation separate a solute from a solvent?

  By heating the solution until the solvent evaporates
• What is the definition of an impure substance?

  A substance with different substances mixed in
• What does it mean if a substance is insoluble?

  It cannot dissolve in a certain solvent
• What is a mixture?

  Substances mixed but not chemically combined
• What is the solubility of a substance?

  The mass that dissolves in 100 g of water
• What happens when a mixture is saturated?

  No more solute can dissolve in the solvent
• What are the two parts of a solution?

  • Solute: the solid added
  • Solvent: the liquid used
• What are the methods to separate mixtures?

  1. Chromatography
  2. Distillation
  3. Evaporation
  4. Filtration
• How does chromatography work?

  By observing how fast substances move on paper
• What is the process of distillation?

  The solution is heated to form gas, then liquid
• What is the solid left on filter paper called?

  Residue
• What does a fixed melting point indicate about a substance?

  It is a pure substance
• How can you tell if a substance is impure from a temperature-time graph?

  It shows a range of melting points
• What is the melting point of pure water?

  0°C
• What happens to pure water at 120°C?

  It will be in a gaseous state
• What is the boiling point of pure water?

  100°C
• What is the difference between a mixture and a compound?

  Mixtures can be separated; compounds cannot
• What is the definition of a compound?

  Substances bonded together chemically
• How can you separate iron from a mixture of iron and sulfur?

  Using filtration
• What is the role of a filter paper in filtration?

  To separate solid from liquid mixtures
• What is the purpose of a sieve?

  To separate particles based on size
• How can you separate sand and salt?

  By using filtration and evaporation
• What is the conservation of mass in a solution?

  The mass of solute plus solvent equals solution mass
• What is the mass of a solution if 10 g of salt is added to 50 g of water?

  60 g
• How can you check if salt is still in a solution?

  By measuring the mass of the solution
• What are the characteristics of pure substances?

  • Fixed melting and boiling points
  • Consistent properties throughout
  • Cannot be separated by physical means
• What are the characteristics of mixtures?

  • Variable melting and boiling points
  • Components can be separated
  • No fixed composition
• What is the difference between solute and solvent?

  • Solute: substance that dissolves
  • Solvent: liquid that dissolves the solute
• What is the process of dissolving?

  • Solute particles spread out in solvent
  • Solvent particles interact with solute
  • Results in a homogeneous mixture
• What is a solution?

  A mixture of a liquid with a solid or gas
• What is a solute?

  The substance that dissolves in a solution
• What are the units of mass?

  Grams or kilograms
• What are the units of temperature?

  Degrees
• Why is calcium carbonate insoluble in water?

  Its particles cannot mix with water
• What is the solubility of a substance?

  The mass of solute that dissolves in 100g of water
• How does temperature affect solubility?

  Solubility usually increases with temperature
• What is filtration?

  A method to separate solids from liquids