Chemistry Finals

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Chemistry Finals
2013-01-20 00:11:50

Final ahhh
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  1. Relative atomic mass
    The mass of one mole of atoms of an element
  2. Relative molecular mass
    Calculated by adding the relative atomic masses of the atoms making up the molecule
  3. Empirical formula
    • Gives the ratio of the atoms of different elements in a compound. 
    • Molecular formula expressed as its simplest ratio
  4. Molecular formula
    • Shows the actual number of atoms of each element present in a molecule
    • Composition of a molecule is given by its molecular formual
  5. Solute
    The less abundant component in a solution
  6. Solvent
    The more abundant component in a solution
  7. Solution
    • Mixtures of two components
    • Solute and Solvent
  8. Concentration
    The composition of a solution
  9. Mass number
    The number of protons plus the number of neutrons in an atom
  10. Atomic number
    The number of protons in the nucleus
  11. Isotopes of an element
    Atoms of the same element with different numbers of neutrons or (mass number)
  12. Uses of radioisotopes
    • generate energy in nuclear power stations
    • sterilize surgical instruments in hospitals
    • preserve food
    • fight crime
    • detect cracks in structural materials
    • kill or save human lifes
  13. What is  the mass spectrometer used for?
    The masses of the different isotopes and their relative abundance can be measured using a mass spectrometer
  14. Stages of operation in mass spectrometer
    • Vaporization
    • Ionization
    • Acceleration
    • Deflection
    • Detection
  15. Vaporization
    Make a gas
  16. Ionization
    • Make an ion
    • atoms are hit with high-energy electrons which knock out electrons, thus producing positively charged ions
  17. Acceleration
    • Makes the ion go fast
    • the positive ions are attracted to negatively charged plates. They are accelerated by an electric field and pass through a hole in the plate
  18. Deflection
    Sort/separate ions by mass and charge
  19. Detection
    Determines ions
  20. Describe how the mass spectrometer may be used to determine relative atomic mass using the 12C scale.
    • Carbon is a very common element which is easy to transport and store because it is a solid.
    • Carbon-12 is the most abundant isotope of carbon
  21. Describe the electromagnetic spectrum
    Ultraviolet, visible and infrared regions
    • Infrared waves have a longer wavelength than red light and ultraviolet waves a shorter wavelength than violet.
    • Shorter waves, purple = high energy
    • Longer waves, red = low energy
  22. Wavelength 
    • The distance between two successive crests
    • Different colors of visible light have different wavelengths; red light has a longer wavelength than blue light
  23. Frequency
    • The number of waves which pass a point in one second
    • The shorter the wavelength, the higher the frequency
    • Blue light has a higher frequency than red light
  24. Energy across the spectrum
    • purple highest energy
    • blue high energy
    • green median enrgry
    • yellow moderate energy
    • orange low energy
    • red lowest energy
  25. Distinguish between a continuous spectrum and a line spectrum
    Continuous spectrum has all colors/wavelengths/ frequencies whereas line spectrum has only lines of sharp/discrete/ specific colors/ wavelengths/ frequencies
  26. Explain how the lines in the emission spectrum of hydrogen are related to the electron energy levels.
    The hydrogen atom gives out energy when an electron falls from a higher to a lower energy level. Hydrogen produces visible light when the electron falls to the second energy level (n=2). The transitions to the first energy level correspond to a higher energy change and are in the ultraviolet region of the spectrum. Infrared radiation is produced when an electron falls to the third or higher energy levels
  27. First ionization energy
    Energy required to remove an electron from an atom
  28. Electronegativity
    Ability of an atom to attract electrons in a chemical bond
  29. Which trends decrease down a group?
    • Electronegativity
    • Ionization energy
  30. Which trends increase down a group?
    Atomic Radius
  31. Which trends decrease across a period?
    Atomic Radius
  32. Which trends increase across a period?
    • Electronegativity 
    • Ionization energy
  33. Write reactions for lithium and water and potassium and water
    • Li+ H2O à LiOH + H2
    • K+ H2O à KOH + H2
  34. Likely to occur?
    Cl2+ I-
    yes Cl- + I2
  35. Likely to occur?
    Cl2+ Br-
    yes Cl- + Br2
  36. Likely to occur?
    I2+ Br-
  37. Likely to occur?
    I2+ Cl
  38. Likely to occur?
    Br2+ Cl-
  39. Likely to occur?
    Br2+ I-
    yes Br- + I2
  40. List the oxides formed by the period three elements.
    • Na2O
    • MgO
    • Al2O3
    • SiO2
    • P4O10
    • SO3
    • Cl2O7
  41. Distinguish between precision and accuracy
    • Precision: getting the same thing every time
    • ex. Hitting the rim of a basketball hoop each time in the same spot
    • Accuracy: getting the exact thing
    • ex: the ball going through the hoop
  42. Describe how the effects of random uncertainties may be reduced
    through repeated readings