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Chemistry

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  • 17. State the charge and location of neutrons.
    Neutral, in nucleus.
  • 7. Explain the process of distillation.
    Separation by boiling point differences.
  • 6. Name 7 physical separation methods for mixtures and give two examples.
    Filtration, distillation, chromatography, decantation, evaporation, centrifugation, sublimation. Ex: salt from water (evaporation), oil + water (decantation).
  • 25. What is the charge of an atom with 12 protons and 10 electrons?
    +2 charge.
  • 13. What experiment did Rutherford conduct and what did he discover?
    Gold foil experiment; discovered nucleus.
  • 22. Calculate the number of protons in an atom with atomic number 17.
    17 protons.
  • 4. Give two examples of homogeneous mixtures.
    Salt water, air.
  • 30. How do solids, liquids, and gases differ?
    Solids: fixed shape/volume. Liquids: fixed volume, no shape. Gases: no shape/volume.
  • 28. How many protons does Cl⁻ have?
    17 protons.
  • 12. What was Thomson’s model of the atom called?
    Plum pudding model.
  • 33. How do pressure and temperature influence state changes?
    Higher pressure = higher boiling point. Lower pressure = lower boiling point.
  • 29. What is the difference between mass number and atomic number?
    A = protons + neutrons; Z = protons.
  • 3. What is the difference between a homogeneous and a heterogeneous mixture?
    Homogeneous = uniform; Heterogeneous = non-uniform.
  • 23. Calculate the number of electrons in a neutral atom of oxygen (Z = 8).
    8 electrons.
  • 16. State the charge and location of protons.
    Positive, in nucleus.
  • 5. Give two examples of heterogeneous mixtures.
    Salad, sand + water.
  • 26. Identify if an atom with 15 protons and 18 electrons is a cation or anion.
    Anion (–3).
  • 27. How many electrons does Na⁺ have?
    10 electrons.
  • 2. Define chemical property and give one example.
    Describes ability to change identity; e.g., flammability.
  • 31. What happens during melting, freezing, evaporation, condensation, sublimation?
    Energy and arrangement of particles change (gain/lose).
  • 24. Calculate the number of neutrons in carbon-14.
    6 protons, 8 neutrons.
  • 11. State Dalton’s atomic theory.
    Atoms indivisible, identical per element, combine in ratios.
  • 21. Define anion and give an example.
    Negative ion; e.g., Cl⁻.
  • 9. Define atom.
    Smallest unit of an element.
  • 15. What are the three main subatomic particles?
    Protons, neutrons, electrons.
  • 10. Define molecule.
    Two or more atoms bonded together.
  • 18. State the charge and location of electrons.
    Negative, outside nucleus.
  • 14. Describe Bohr’s atomic model briefly.
    Electrons orbit in fixed energy levels.
  • 19. Define ion.
    Atom with charge (lost/gained electrons).
  • 32. Why does temperature remain constant during a change of state?
    Energy is used to change state, not to raise temp.
  • 20. Define cation and give an example.
    Positive ion; e.g., Na⁺.
  • 34. Why are changes of state important in life, industry, or biotech?
    Daily life (cooking), industry (fuel distillation), biotech (freeze-drying).
  • 1. Define physical property and give one example.
    Observed without changing substance; e.g., color.
  • 8. Explain the process of filtration.
    Separation using a barrier to trap solids.