chem

• What are the two types of distillation mentioned?

  Simple distillation and fractional distillation
• What is the purpose of simple distillation?

  To separate a liquid from a solution
• How can simple distillation be used with seawater?

  To separate pure water from seawater
• What equipment is used in simple distillation?

  A flask, thermometer, condenser, and heating device
• Why is the flask sealed with a bung?

  To prevent gas from escaping
• What is the function of the thermometer in distillation?

  To measure the temperature inside the flask
• How does the condenser work in simple distillation?

  It cools vapor to condense it into liquid
• What happens to the vapor in the condenser?

  It cools and condenses into liquid form
• What is left in the flask after distilling seawater?

  Salt
• What is the main technique used for separating mixtures of liquids?

  Fractional distillation
• Why can't simple distillation separate methanol, ethanol, and propanol?

  They have similar boiling points
• What is the role of the fractionating column in fractional distillation?

  To separate liquids with similar boiling points
• What features does the fractionating column have?

  Glass rods and a temperature gradient
• How does the temperature gradient in the fractionating column help in separation?

  It allows lower boiling point liquids to rise
• What happens to ethanol and propanol in the fractionating column?

  They condense back into liquid form
• What model did J.J. Thompson propose in 1897?


  The plum pudding model
• What did Thompson's experiments reveal about atoms?

  Atoms contain negatively charged particles
• How did Thompson describe the atom in his model?

  A ball of positive charge with electrons
• What significant experiment did Ernest Rutherford conduct in 1909?

  Fired alpha particles at gold foil
• What did Rutherford expect to happen in his gold foil experiment?

  Alpha particles should pass through gold
• What unexpected result did Rutherford observe?

  Some alpha particles were deflected
• What conclusion did Rutherford draw from his experiment?

  Atoms have a compact nucleus
• Who proposed a solution to Rutherford's model flaw in 1913?

  Niels Bohr
• How did Bohr suggest electrons behave?

  They orbit the nucleus in shells
• Why is Bohr's model important?

  It prevents the atom from collapsing
• What did further experiments by Rutherford discover about the nucleus?

  The nucleus contains protons
• What is the current understanding of the atom's structure?

  • Atoms consist of a nucleus
  • Nucleus contains protons and neutrons
  • Electrons orbit the nucleus in shells
  • Electrons prevent the atom from collapsing
• What are the key historical models of the atom?

  1. Atomic theory by Democritus
  2. Solid spheres by John Dalton
  3. Plum pudding model by J.J. Thompson
  4. alpha scattering by Ernest Rutherford
  5. nuclear model by Niels Bohr
• What did Mendeleev's periodic table predict?

  New elements not yet discovered
• How are elements arranged in the periodic table?

  By increasing atomic number
• What does the atomic number represent?

  The number of protons in an atom
• What does the atomic number indicate?

  How many protons an atom has
• What does the mass number represent?

  Total number of protons and neutrons
• What pattern did Mendeleev observe in the elements?

  Repeating chemical properties at intervals
• What are the horizontal rows in the periodic table called?


  Periods
• What do elements in the same vertical column share?

  Similar chemical properties
• Why do elements in the same group have similar properties?

  They have the same outer shell electrons
• How do Group 1 elements react with water?


  They react violently
• What trend is observed in Group 1 elements as you move down the group?

  They become more reactive
• How does reactivity change in Group 7 elements as you go down the group?


  They become less reactive