Science - Chemistry

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Science - Chemistry
2014-05-03 08:55:56
Chemistry Ionic Bonding
Ionic Bonding
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  1. What are the Noble Gases ?
    Helium(He), Neon (Ne), Argon (Ar), Krypton(Kr) Xenon (Xe) and Radon (Rn).
  2. What are the properties of the Noble Gases?
    (3 points)
    • Group 0(sometimes called 8)
    • Full outer shell
    • Stable
  3. What are the Alkali Metals?
    Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Caesium (Cs) and Francium (Fr).
  4. What are the properties of the Alkali Metals?
    (5 points)
    • Group 1
    • Soft
    • Reactive
    • React vigorously with water
    • Become more reactive as you go down the group
  5. What are the Halogens?
  6. What are the properties of the Halogens?
    • reactive non-metals
    • darker as you go down the group
    • reactivity decreases as you go down the group 
    • boiling points increases as you go down the group
  7. What is the Mass of a Proton?
  8. What is the Mass of a Neutron?
  9. What is the Mass of an Electron?
    Negligible/ Nearly 0
  10. What is the charge of a Proton?
  11. What is the charge of a Neutron?
    Neutral/ 0
  12. What is the charge of an Electron?
  13. Where in an atom would you find Protons?
  14. Where in an atom would you find Neutrons?
  15. Where in an atom would you find Electrons?
    Energy shells around the Nucleus
  16. What does AMU stand for ?
    Atomic mass unit
  17. What does the Atomic Number show?
    The number of protons
  18. What are equal to protons in an atom?
  19. What is the mass Number ? (atomic mass)
    • mass of nucleus
    • (protons + neutrons)
  20. How do you work out the number of neutrons?
    No. neutrons = mass number - atomic number
  21. Why are atom neutrally  charged?
    They have an equal amount of protons and electrons
  22. What are isotopes?
    • Atoms of the same element that have different number of neutrons in their nucleus
    • e.g.146C   126C
  23. True or False the chemical properties of isotopes are different ?
    False because they have the same number of electrons
  24. What is the relative atomic mass? (Ar)
    • The average mass of all isotopes taking into account their relative abundance
    • abundance - how much
  25. How do you work out the Ar ?
  26. How do you work out the mass of a compound?
    • Add up the relative atomic mass of each atom
    • CO2
    • 12+2(16)
  27. How many electrons in shell ...
    • a) 2
    • b)8
    • c)8
  28. What is Ionic Bonding?
    • Bonding between a Metal and a Non- metal
    • The metal loses an electron and the non-metal gains it.
    • Held together through electrostatic attraction.
  29. What are the properties of an Ionic compound?
    • Conduct electricity When molten or dissolved in Water
    • Form an ionic lattice
    • High melting and boiling points
    • Hard to separate
    • can decompose back to their elements
  30. What is covalent bonding?
    • Bonding between two Non-metals
    • They share electrons to achieve a noble gas state
    • Held together by intermolecular forces
  31. What are the properties of a simple covalent structure?
    • Do not conduct electricity in any state
    • Low melting and boiling point (even when the force is strong)
    • Insoluble in water (may dissolve in other liquids)
    • Liquid or gas at room temperature
  32. What are the properties of a giant covalent structure?
    • Regular arrangement e.g. a diamond
    • High melting point
    • Very hard
    • Don't generally conduct electricity
    • Insoluble in all liquids
  33. What are the properties of a Diamond?
    • Hardest natural substance known on earth
    • Shiny / sparkly
    • very high melting point 3500°c +
    • held together by strong covalent bonds
    • each carbon has four bonds
    • made entirely of carbon
    • Does not conduct electricity because all the electrons are held together  between atoms
  34. What are the properties of Graphite?
    • Made entirely of carbon
    • soft
    • used in pencils
    • has a layered structure
    • held together by strong covalent bonds but with weak intermolecular forces allowing them to slide
    • high melting point
    • each carbon atom uses three of its bonds
    • has delocalised electrons as only 3 are used in bonding
    • can conduct electricity
  35. what are the properties of silicon dioxide?
    • High melting point
    • strong covalent bonds
    • used in sandpaper
    • each silicon atom makes four bonds to oxygen atoms
  36. What's a thermosetting polymer?
    It can only be moulded once as it sets when it comes into contact with heat
  37. What's a thermo softening polymer?
    Can be moulded many times as when it comes into contact with heat it melts
  38. Do Polymers have a melting range or point?
    Melting range as they are not pure subatances
  39. Why can thermosetting only be moulded once?
    They have cross links that hold them in position
  40. What difference makes LDPE and HDPE?
    They are made under different conditions and have a different catalyst
  41. What does malleable mean?
    Can change shape (soft / flexible)
  42. What does ductile mean?
    Can stretch without snapping
  43. what does sonorous mean?
    When it is struck it will make a sound
  44. Why do metals conduct electricity well?
    They have free moving electrons (delocalised)
  45. What are properties of metal?
    • Ductile 
    • Sonorous
    • malleable
    • have high melting pints
  46. What is metallic bonding?
    • Bonding between two metals
    • Atoms become positively charged as the free electrons move away
    • The sea of electrons mean the atoms are attracted
  47. How do you work out the percentage of an element in a compound?
    • Atomic mass of the element
    • divided by
    • atomic mass of compound
    • then times 100
    • e.g.
    • % of Carbon in CO2
    • 12/44 x 100 = 27.27 %
  48. What is the empirical formula?
    The smallest, whole, number of atoms in a formula
  49. 9g of Aluminium reacts with 35.5g of Chlorine
    What is the empirical formula?
    • element                   Al                               Cl
    • Mass                      9g                           35.5g

    Ar                                   27                         35.5   

    Mass/Ar                27/9 = 0.33333...    35.5/35.5=1

    • /smallest         0.3../0.3...=1             1/0.3...=3
    • empirical formula        AlCl3
  50. Instructions for Empirical formula
    • Draw a table with the number of elements +1 columns
    • Draw 6 rows Labelled Element, Mass, Ar, Mass/Ar Mole ratio (/ smallest) and Empirical formula
    • In the rows fill in the information
    • Make sure the numbers that are created after /smallest are whole numbers
    • if not times to make the smallest whole number (e.g. 1.5 and 2 times them both by 2 to get 3 and 4)
    • write your numbers in the correct places after the right element and you have your empirical formula
  51. how to work out the mass that can be made from so much of an element?
    What mass of TiO2 can be made from 3.4g of Ti?
    • Ti + 02 → TiO2
    • 1 mole of .... is
    • Ti = 48g O2 =32g TiO2 = 80g
    • For Ti M=W/R = 3.4/48= 0.070833333... mol
    • For TiO2 We make 0.070833333 mol
    • W=MxR = 0.07083333... x 80
    • = 5.666...g
  52. How much limestone would you need to make 5.6g of quick lime?
    • CaCO3 → CaO  + CO2
    • =100g        56g      44g
    • 5.6 = 56/10
    • 100/10= 10
    • 10g of CaCO3
  53. How much MgO will be made from 2g of Mg?
    • 2Mg + O2 → 2MgO
    • W=2g M=? R=24
    • 2/24 =0.0833333..
    • Molar ratio is 1:1 so 0.083333. mol of Mg makes 0.08333... of MgO
    • W=MxR
    • W= 0.08333.. x 40 = 3.3333...g
  54. We expected to get 3.333..g of MgO ut we only got 1.65g
    What's the percentage yield?
    • 1.65/3.333333...  x100 = 49.5%
    • 50%

    Percentage yield = actual yield /theoretical yield x100
  55. What is chromatography used for ?
    To separate different substances dissolved in a liquid
  56. How is gas Chromatography carried out?
    The sample is dissolved in a solvent, then injected into one end of the column.An unreactive gas - usually nitrogen - carries the sample through the column.Different substances in the sample travel through the column at different speeds and so become separated from each other.The separated substances leave the column one after the other. As they leave, they are detected by a detector.
  57. What is the retention time ?
    The time taken for a substance to travel through the column
  58. What do the peaks show?
    the number of compounds present in the sample
  59. What does the position of each peak show?
    the retention time
  60. What does a mass spectrometer do?
    A mass spectrometer is able to identify substances very quickly and accurately. It can detect very small amounts
  61. what is a GC-MS?
    this combined GC-MS method allows the separated substances leaving the column of the GC machine to be detected.
  62. mass spectrometry -higher
    The mass spectrometer can be used to identify substances quickly and accurately, and in very small amounts. It can also provide the relative formula mass of the substances separated by gas chromatography. The peak furthest to the right in a mass spectrum is called the 'molecular ion peak'. Its relative mass is the relative formula mass of the substance being analysed.