solutions and mixtures

• A heterogeneous solution consists of two or more phases that are not uniformly mixed.
• distillation is the physical separation technique that is based on the difference in boiling points of the substance.
• fractional distillation used to separate crude oil.
• crystallization is a separation technique that results in the formation of pure solid crystals of a substance from a solution containing the dissolved substance
• sublimation is the process which a solid change into vapor without melting.
• chromatography: separates components of a mixture based on the distinctive attraction to the mobile phase and stationary phase.
• Henry's law: the amount of gas that can be dissolved in a liquid is directly proportional to the pressure of the gas.
• magnetic attraction: attracts magnetic substances from non magnetic ones
• Molarity (M) = moles of solute / volume of solution (L)Molality (m) = moles of solute / mass of solvent (kg)
• The dilution rule states that the product of the initial concentration and volume is equal to the product of the final concentration and volume:

  C1 * V1 = C2 * V2
• 1. Boiling point elevation: When a solute is dissolved in a solvent, it raises the boiling point of the solution compared to the pure solvent.
• Freezing point depression: Conversely, adding a solute lowers the freezing point of a solution compared to the pure solvent.
• 3. Vapor pressure lowering: The presence of a solute decreases the vapor pressure of the solvent. This means that less pure solvent evaporates from the solution compared to the pure solvent alone.
• 4. Osmotic pressure: When two solutions with different concentrations are separated by a semipermeable membrane (a membrane that allows only solvent molecules to pass through), water potential will naturally flow towards the more concentrated solution(lower water potential).
• The Tyndall effect, also known as Tyndall scattering, is the phenomenon where light is scattered by particles suspended in a medium, making the path of the light beam visible.
• Particle size: The smaller the particles, the more effective they are at scattering light.

  Wavelength of light: Shorter wavelengths (blue light) scatter more effectively than longer wavelengths (red light).

  • Concentration of particles: As the concentration of particles increases, the light scattering becomes more intense, making the beam more visible.
• Brownian motion, in essence, is the random and continuous movement of microscopic particles suspended in a fluid (liquid or gas) due to their collisions with the surrounding fluid molecules.
• Substance:

  • A substance is the most fundamental category, representing a pure form of matter with a definite and uniform composition.
  • Examples: gold, water, oxygen gas, table salt.
  • Substances can be either elements (made of only one type of atom) or compounds (made of atoms of different elements chemically combined).
• Mixture:

  • A mixture is a physical combination of two or more substances that retain their own individual chemical identities.
  • The components of a mixture can be easily separated by physical means like filtration, distillation, or chromatography.
  • Examples: air (mixture of gases), salad (mixture of ingredients), saltwater (mixture of salt and water).
• Compound:

  • A compound is a specific type of substance formed by the chemical combination of two or more elements in a fixed ratio.
  • The elements in a compound undergo a chemical reaction, losing their individual properties and forming a new substance with unique properties different from its constituents.
  • Compounds cannot be separated into their constituent elements by simple physical means.
  • Examples: water (H2O), carbon dioxide (CO2), table salt (NaCl), sugar (C6H12O6).
• • Composition: Mixtures have variable compositions, while compounds have fixed compositions.
• • Properties: Mixtures retain their chemical properties, while compounds have unique properties different from their elements.