Required Practicals

• What are the three types of variables in investigations?

  Independent, dependent, and controlled variables
• Why is it important to state the equipment used for measurements?

  It ensures clarity and accuracy in results
• What safety equipment is commonly used when working with chemicals?

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

  By aligning your eye with the measurement
• What is the benefit of taking multiple measurements?

  To calculate a mean for accuracy
• Why is it acceptable to write answers in bullet point format?

  It helps track different points clearly
• How should you phrase instructions in a practical report?

  Use proper English and full sentences
• What is the process for making salt crystals in a practical?

  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
  5. Collect solid crystals of copper sulfate
• What is the setup for electrolysis in a practical?

  1. Place sodium chloride solution in a beaker
  2. Insert two inert carbon electrodes
  3. Connect electrodes to a power supply
  4. Identify anode (positive) and cathode (negative)
  5. Observe reactions based on ion reactivity
• What happens at the cathode during electrolysis?

  A positive ion is reduced
• What happens at the anode during electrolysis?

  A negative ion is oxidized
• How does the reactivity of ions affect electrolysis outcomes?

  More reactive cations stay in solution
• What is the procedure for measuring temperature changes in a reaction?

  1. Use a polystyrene cup for insulation
  2. Insert a thermometer through a lid
  3. Add reactant and record maximum temperature
  4. Vary volumes of alkali to observe temperature changes
  5. Draw lines of best fit for temperature data
• What are the two methods to observe rates of reaction?

  1. Measure gas volume produced over time
  2. Observe turbidity change in sodium thiosulfate and hydrochloric acid reaction
• What is the purpose of chromatography?

  To separate different solutes in a mixture
• What is the process of chromatography?

  1. Apply a spot of mixture on chromatography paper
  2. Draw a pencil line as a reference
  3. Hang paper in distilled water without touching
  4. Allow capillary action to separate particles
  5. Calculate RF values for identification
• What is the definition of distilled water?

  Water that is purified through distillation
• What is desalination?

  Removing salt from water
• What is the procedure for titration in neutralization?

  1. Measure alkali with a glass pipet in a conical flask
  2. Add an indicator like methyl orange
  3. Fill burette with acid and open the tap
  4. Perform a rough titration to estimate volume
  5. Add acid dropwise for accurate measurement
• How do you calculate the concentration of an acid in titration?

  Using moles of acid divided by volume
• What are the methods to identify metal and non-metal ions?

  1. Flame test for metals
  2. Hydrochloric acid for carbonate ions
  3. Silver nitrate for halogen ions
  4. Barium chloride for sulfate ions
• What indicates the presence of carbonate ions?

  Bubbles forming with hydrochloric acid
• What color precipitate indicates chloride ions?

  White precipitate
• What color precipitate indicates bromide ions?

  Cream precipitate
• What color precipitate indicates iodide ions?

  Yellow precipitate
• What indicates the presence of sulfate ions?

  White precipitate with barium chloride
• What should you not see if water is well purified?

  Positive tests for sodium or chloride ions