everything

• Nanoparticles are useful as catalysts beacause they have a large surface ares so therefore increase the rate of reaction
• What is the green house effect

  carbon dioxide/greenhouse gases is produced . They absorb heat radiated from earth and reradiate the heat back into the atmosphere
• why things are in the same homologus series

  same general formula

  trend in physical properties

  same functional group
• Group 1 elements are the alkali metals
• Group 1 elements


  • They have one electron in their outer shell
  • As you descend the group, the elements become more reactive
  • The atoms get larger as you descend the group, the outer shell electron is further from the nucleus and more shielded, making it easier to lose the electron
• Reactivity of Group 1 elements

  • They are extremely reactive and must be stored in oil to prevent reaction with moisture
  • They are soft and can be cut with a knife
  • They oxidize very easily, going from shiny to oxidized quickly on exposure to air
  • They have low melting and boiling points
  • They have low density and float on water
• Reactions of Group 1 elements

  1. Reaction with oxygen to form oxides

  2. Reaction with cold water to form hydroxides

  3. Reaction with halogens to form salts

  4. Participate in ionic bonding
• Observations when Group 1 elements are added to water

  • They fizz, releasing hydrogen gas
  • They float and move around
  • They form a small ball that eventually dissolves
  • The resulting solution turns blue with universal indicator, indicating it is alkaline
• Lithium does not produce a flame when added to water, but sodium produces an orange flame and potassium produces a lilac flame
• Group 1 metals plus cold water form a metal hydroxide plus hydrogen
• Group 1 metals below potassium (e.g. francium) will have more violent reactions with water
• The halogens are the elements in Group 7 of the periodic table
• States of the halogens at room temperature

  • Fluorine - yellow gas
  • Chlorine - green gas
  • Bromine - red-brown liquid
  • Iodine - grey solid
• Iodine undergoes sublimation


  It turns directly from a solid to a gas
• Reactions of halogens with hydrogen

  1. Form hydrogen halides

  2. Hydrogen halides are very acidic and poisonous

  3. Hydrogen halides are very soluble in water
• More reactive halogens can displace less reactive halogens from their compounds
• Reactivity of halogens


  • Fluorine is the most reactive
  • Iodine is the least reactive
  • Larger atoms with more electron shells are less reactive
• Uses of halide salts


  • Sodium chloride - table salt
  • Sodium fluoride - in toothpaste
  • Sodium bromide - disinfectant in swimming pools
  • Sodium iodide - additive in table salt
• Reaction of halogens with hydrogen

  1. Form hydrogen halides

  2. Hydrogen chloride gas dissolves in water to form hydrochloric acid
• Test for chlorine gas: it bleaches damp litmus paper
• Reactivity of halogens


  Can be determined by heating with iron wool - fluorine bursts into flames, chlorine glows brightly, bromine glows dully, iodine just changes color
• Group 0 elements


  • Also known as the noble gases
  • They are unreactive because they have full outer electron shells
• Uses of noble gases

  • Krypton - in lighting and photography
  • Argon - in light bulbs and wine barrels
  • Helium - in balloons and airships
  • Neon - in illuminated signs
• Effect of temperature on reaction rate

  • Increases rate - particles have greater kinetic energy, more frequent and harder collisions
• Effect of concentration on reaction rate

  • Increases rate - more particles in the same volume, more frequent collisions
• Effect of surface area on reaction rate

  • Increases rate - more surface area, more frequent collisions
• Measuring reaction rates


  1. Change in volume over time

  2. Change in concentration over time

  3. Mass change over time (e.g. measuring CO2 production)

  4. Time for a cross to disappear due to precipitate formation
• Reasons for using catalysts in industrial processes

  To increase profits by making products faster, at lower temperatures, and without the catalyst being consumed
• Enzymes


  Biological catalysts that speed up reactions without being consumed
• How enzymes work


  They have an active site where the substrate binds, following the lock and key theory
• Endothermic and exothermic reactions

  • Endothermic - absorb heat energy, positive ΔH
  • Exothermic - release heat energy, negative ΔH
• Exothermic reactions heat up the surroundings, endothermic reactions cool them down
• Active site


  Specific site on enzymes where the substrate binds
• Lock and key theory

  The way in which the enzyme and substrate fit together
• Endothermic


  Takes in heat energy
• Exothermic


  Gives out heat energy
• Exothermic reaction


  Gets hot
• Endothermic reaction


  Gets cold
• Nitric acid is added to potassium hydroxide solution
• Pipette or burette


  Precise apparatus to measure 25cm cubed of potassium hydroxide solution