required practicals

• What are the three types of variables in investigations?

  Independent, dependent, and controlled variables
• What safety equipment should be used when working with chemicals?

  Goggles and gloves
• How can you reduce parallax error when measuring?

  Align your eye with the measurement mark
• What is the benefit of taking multiple measurements?

  To calculate a mean and reduce errors
• What is the process for making salt crystals?

  1. Heat concentrated sulfuric acid in a beaker.
  2. Add excess copper oxide until unreacted powder remains.
  3. Filter out unreacted copper oxide.
  4. Gently heat the copper sulfate solution in an evaporating basin using a water bath.
  5. Crystals of copper sulfate will form.
• Describe the electrolysis process using sodium chloride solution.

  1. Place sodium chloride solution in a beaker.
  2. Insert two inert carbon electrodes.
  3. Connect electrodes to a power supply.
  4. Positive ions are reduced at the cathode; negative ions are oxidized at the anode.
  5. If sodium is present, hydrogen gas is produced; if copper chloride is present, copper is deposited.
• What happens to the maximum temperature in a reaction with increasing alkali volume?

  It decreases after reaching excess alkali
• What are the two practicals to observe the rate of reaction?

  1. Measure gas volume produced over time.
  2. Observe the time taken for a cross to disappear due to turbidity.
• What is the stationary phase in chromatography?

  Chromatography paper or filter paper
• How do you calculate the RF value in chromatography?

  Distance solute moves / distance mobile phase moves
• What is the process of water purification through distillation?

  1. Heat water in a flask.
  2. Use a condenser to cool vapor.
  3. Collect distilled water as it condenses.
  4. Distilled water is potable if low in salt and microbes.
• What is the purpose of a titration in neutralization?

  • Determine the concentration of an acid or alkali.
  • Use an indicator to identify neutralization point.
  • Calculate unknown concentration using moles and volume.
• How can metal ions be identified using a flame test?

  Dip nichrome wire in the compound and heat
• What indicates the presence of carbonate ions in a solution?

  Bubbles form when hydrochloric acid is added
• What happens when silver nitrate is added to chloride ions?

  A white precipitate forms
• What is the result of adding hydrochloric acid to barium chloride?

  A white precipitate indicates sulfate ions
• What are the expected tests for identifying sodium and chloride ions?

  • Sodium: Flame test shows yellow flame.
  • Chloride: Silver nitrate test shows white precipitate.