Chemistry Quiz

• Things that can increase the rate of a reaction

  • Increase surface area for solids
  • Increase concentration for solutions
  • Increase pressure for gases
• Things that can increase the rate of a reaction

  • Increase temperature
  • Use a catalyst
• Calculating rate of reaction from a graph

  1. Draw a tangent

  2. Find the gradient of the tangent

  3. Gradient = change in y / change in x
• Le Chatelier's principle


  If a system at equilibrium is subjected to a change, the system will adjust to counteract the change
• Increasing concentration or pressure


  Favours the reaction that makes the fewest moles (forward reaction)
• Increasing temperature


  Favours the endothermic reaction
• Hydrocarbons


  Organic molecules that only contain carbon and hydrogen atoms
• Alkanes


  Hydrocarbons with only single covalent bonds between carbon atoms
• Alkenes


  Hydrocarbons with a double covalent bond between carbon atoms
• Fractional distillation of crude oil

  1. Heated at the bottom

  2. Vaporized into gas

  3. Recondense at different heights due to different boiling points
• Complete combustion


  Hydrocarbon reacts with oxygen to make water and carbon dioxide
• Incomplete combustion


  Hydrocarbon reacts with less oxygen to make carbon monoxide or carbon
• Test for alkenes


  • Turns bromine water from orange to colourless
• Reaction of water with an alkane


  Makes an alcohol
• Oxidation of an alcohol


  Produces a carboxylic acid
• Cracking of an alkane

  1. Requires high temperature (550°C for catalytic, 800°C for steam)

  2. Always produces a shorter alkane and an alkene
• Rf value in chromatography

  Ratio of distance moved by substance to distance moved by mobile phase
• Tests for gases


  • Hydrogen - squeaky pop with lit splint
  • Oxygen - relights glowing splint
  • Carbon dioxide - turns limewater cloudy
  • Chlorine - bleaches blue litmus paper
• Atmospheric pollutants


  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen oxides
  • Carbon particulates
• Making potable water


  1. Filter to remove particles

  2. Sterilize with chlorine, ozone or UV

  3. Desalinate salt water by distillation or reverse osmosis
• Traditional metal extraction methods

  • Electrolysis
  • Displacement reactions
• New metal extraction methods

  • Phytomining
  • Bioleaching
• Corrosion of iron, copper, aluminium

  Iron - forms iron oxide (rust)

  Copper - forms copper oxide (green)

  Aluminium - forms aluminium oxide (white)
• Preventing corrosion


  Use a sacrificial metal that corrodes first (galvanizing)
• Why alloys are stronger than pure metals

  • Different sized atoms disrupt the lattice structure, making it harder for layers to slide past each other
• Optimal conditions for Haber process

  • Temperature of 450°C

  Pressure of 200 atmospheres

  Catalyst used
• How can the rate of reaction be found?


  By measuring the quantity of reactant used or the quantity of product formed over time
• Mean Rate of Reaction (by measuring quantity of reactant used)


  Quantity of Reactant Used/Time Taken
• Mean Rate of Reaction (by measuring quantity of product formed)


  Quantity of Product Formed/Time Taken
• Factors affecting the rate of chemical reactions

  • Concentration of Reactants
  • Pressure of Reacting Gases
  • Surface Area of Solid Reactants
  • Temperature
  • Presence of Catalysts
• How can we use a gas syringe to calculate the rate of reaction of a reaction in which a gas is formed?

  Add the reactants in a conical flask, seal with bung and collect the gas in a gas syringe. Record how much gas has been made in a given time.
• How can we use a balance to calculate the rate of reaction of a reaction in which a gas is formed?

  Weigh the reactants beforehand, add them both to a conical flask and record the decrease in mass over a given time.
• How can we use apparatus to calculate the rate of reaction in which a solid is formed?

  Add the reactants in a conical flask and time how long it takes for the cross to disappear.
• Precipitate


  A solid product in a chemical reaction
• Collision theory


  A theory that states that chemical reactions can only occur when reacting particles collide with each other and with sufficient energy.
• Activation energy


  The minimum amount of energy that particles must have to react.
• Increasing pressure


  Increases the rate of reaction
• Increasing pressure of reacting gases

  Increases the rate of reaction
• Increasing surface area of reacting solids

  Increases the rate of reaction
• Increasing temperature


  Increases the rate of reaction