Useful Phrases for Labeling (Copy)

🔥 1. Heating & Flame Diagrams

• Bunsen burner with air hole open (blue flame)
  → Use for strong heating (e.g. boiling, decomposition)
• Bunsen burner with air hole closed (yellow flame)
  → Use for gentle heating or when not heating to avoid soot
• Flame applied to the base of the test tube
  → Use in heating solids/liquids in test tube
• Test tube held at an angle using a test tube holder
  → Prevents contents from shooting out when boiling

💨 2. Gas Collection Setups

• Hydrogen gas collected by upward delivery
  → Hydrogen is less dense than air
• Carbon dioxide gas collected by downward delivery
  → CO₂ is denser than air
• Oxygen gas collected over water
  → Oxygen is sparingly soluble in water
• Delivery tube leading from reaction flask to gas jar
  → Always draw and label the direction of gas flow
• Water trough for collecting gas over water
  → Used when the gas is insoluble or slightly soluble in water

🧪 3. Filtration, Crystallization & Evaporation

• Filter paper folded in a cone shape placed inside a funnel
  → Correct method to filter solid from liquid
• Residue remains on the filter paper
  → Insoluble substance
• Filtrate collected in a conical flask
  → Clear liquid that has passed through
• Evaporating dish placed on gauze over tripod
  → For evaporation to dryness or crystallization process
• Crystals form on cooling the saturated solution
  → Indicates crystallization

⚗️ 4. Titration Setup

• Burette filled with dilute sulfuric acid
  → Include chemical name and correct acid/alkali used
• Pipette used to transfer 25 cm³ of sodium hydroxide solution
  → Volume + substance important for accuracy
• Conical flask placed on a white tile
  → Helps to detect color change of indicator
• Indicator added to solution in conical flask
  → Specify name, e.g., phenolphthalein, methyl orange

💧 5. Distillation Setup

• Thermometer bulb positioned at the neck of the flask
  → Measures the boiling point of vapor, not liquid or air
• Cold water in at bottom of condenser, out at top
  → Ensures proper circulation for efficient condensation
• Condenser connected horizontally between flask and beaker
  → Proper orientation of Liebig condenser
• Distillate (e.g. pure water) collected in receiving beaker
  → Always name the collected liquid

🌈 6. Chromatography Setup

• Pencil line drawn 1–2 cm above the base of the paper
  → Baseline must be in pencil (won’t dissolve)
• Ink spots placed on the baseline
  → Multiple colored spots may be tested
• Solvent level below the baseline
  → Prevents ink dissolving into solvent directly
• Solvent front marked after the experiment
  → Required to calculate Rf values

🧫 7. Specific Chemical Test Labels

• Hydrogen peroxide solution with manganese dioxide catalyst
  → Oxygen production experiment
• Glowing splint inserted to test for oxygen
  → Oxygen relights a glowing splint
• Limewater in test tube turns milky in presence of CO₂
  → Test for carbon dioxide
• Damp red litmus paper turns blue → presence of ammonia gas
  → Use “damp” — moisture allows gas to dissolve

🧯 8. Safety Labels (If Asked or Relevant)

• Wear eye protection (safety goggles)
• Use tongs to handle hot apparatus
• Keep flammable substances away from flame
• Use heatproof mat under Bunsen burner

🧠 Pro Tip:

Label what is visible in the diagram. If you draw an apparatus (e.g. funnel, burner, condenser), label it clearly with proper scientific names — avoid generic words like “tube”, “liquid”, or “chemical”.