chemistry

• in an element all of the atoms are the same .
• A compound is 2 or more elements chemically bonded together ( in fixed proportions )
• mixtures are different elements or compounds that are not chemically bonded together
• mixtures can be separated using physical methods such as filtration , distillation and crystallisation
• What is the definition of electrolysis?

  Electrolysis is a process that uses electricity to drive a non-spontaneous chemical reaction.
• What is the primary purpose of electrolysis?

  The primary purpose of electrolysis is to break down a compound using electrical energy.
• What are the key points of electrolysis?

  • Method of separating bonded elements and compounds
  • Requires an electric current to pass through a liquid or solution
  • The liquid must contain ions to conduct electricity
• How can electrolysis be used in a practical example?

  Electrolysis can be used to separate water into hydrogen and oxygen gases.
• What is an electrolytic cell?

  An electrolytic cell is a setup where electrolysis takes place.
• What are the main components of an electrolytic cell?

  1. Electrodes (Anode and Cathode)
  2. Electrolyte
  3. Power source
• What is the role of electrodes in an electrolytic cell?

  Electrodes are conductors where electricity enters and exits the solution.
• What is the anode in an electrolytic cell?

  The anode is the positive electrode in an electrolytic cell.
• What is the cathode in an electrolytic cell?

  The cathode is the negative electrode in an electrolytic cell.
• What is the function of the electrolyte in an electrolytic cell?

  The electrolyte is the solution containing ions that conducts electricity.
• What provides the electrical current in an electrolytic cell?

  The power source provides the electrical current in an electrolytic cell.
• What happens to the electrolyte during electrolysis?

  The electrolyte dissociates into positive and negative ions during electrolysis.
• What happens to positive ions during electrolysis?

  Positive ions (cations) are attracted to the cathode (negative electrode).
• What happens to negative ions during electrolysis?

  Negative ions (anions) are attracted to the anode (positive electrode).
• What occurs at the electrodes during electrolysis?

  At the electrodes, ions either gain or lose electrons, leading to redox reactions.
• In the electrolysis of molten sodium chloride (NaCl), what do sodium ions do?

  Sodium ions (Na+) move to the cathode and gain electrons to form sodium metal.
• In the electrolysis of molten sodium chloride (NaCl), what do chloride ions do?

  Chloride ions (Cl-) move to the anode and lose electrons to form chlorine gas.
• What are some common applications of electrolysis?

  1. Metal extraction (e.g., aluminum from bauxite)
  2. Electroplating (coating objects with metal)
  3. Water purification
  4. Producing chemicals (e.g., chlorine, sodium hydroxide)
  5. Electrolytic cleaning (removing rust or tarnish)
• How is electrolysis used in metal extraction?

  Electrolysis is used to produce pure metals from their ores.
• What is electroplating?

  Electroplating is the process of coating objects with a thin layer of metal.
• How does electrolysis contribute to water purification?

  Electrolysis is used to remove contaminants from water.
• What chemicals can be produced through electrolysis?

  Electrolysis can produce substances like chlorine and sodium hydroxide.
• What is electrolytic cleaning?

  Electrolytic cleaning is the process of removing rust or tarnish from metal objects.
• How does the production of aluminum utilize electrolysis?

  The production of aluminum uses electrolysis to extract the metal from its ore.
• the plum pudding model of an atom suggested it was a ball of positive charge with negative electrons embedded
• electrons were discovered first then protons and then neutrons last
• • Random error causes one measurement to differ slightly from the next. It comes from unpredictable changes during an experiment.
• • Systematic error always affects measurements by the same amount or proportion, provided that a reading is taken the same way each time. It is predictable.
• • weaker forces of attraction between the outermost electron and the nucleus
  • Less energy is required to overcome the force of attraction as it gets weaker, so the outer electron is lost more easily
  • So, the alkali metals get more reactive as you descend the group
• • The Group 1 elements are known as the alkali metals
  • They form alkaline solutions when they react with water
• • Some of alkali metals properties are:
  • They are all soft metals which can easily be cut with a knife
  • They have relatively low densities and low melting points
  • They are very reactive (they only need to lose one electron to become highly stable)
• the halogens get less reactive as you go gown the group
• the noble gases are unreactive as they have a full outer shell so are there for stable
• What topics are covered in AQA GCC chemistry paper 1?

  Atoms, bonding, quantitative chemistry, energy changes
• What is a compound?

  A substance with two or more different atoms bonded
• What is the chemical formula for water?

  H2O