CIE iGCSE Co-ordinated Sciences-C12.1 Experimental design- Study Notes- New Syllabus
CIE iGCSE Co-ordinated Sciences-C12.1 Experimental design – Study Notes
CIE iGCSE Co-ordinated Sciences-C12.1 Experimental design – Study Notes -CIE iGCSE Co-ordinated Sciences – per latest Syllabus.
Key Concepts:
Core
- Name appropriate apparatus for the measurement of time, temperature, mass and volume, including:
(a) stop-watches
(b) thermometers
(c) balances
(d) burettes
(e) volumetric pipettes
(f) measuring cylinders
(g) gas syringes - Describe a:
(a) solvent as a substance that dissolves a solute
(b) solute as a substance that is dissolved in a solvent
(c) solution as a mixture of one or more solutes dissolved in a solvent
(d) saturated solution as a solution containing the maximum concentration of a solute dissolved in the solvent at a specified temperature
(e) residue as a solid substance that remains after evaporation, distillation, filtration or any similar process
(f) filtrate as a liquid or solution that has passed through a filter
CIE iGCSE Co-Ordinated Sciences-Concise Summary Notes- All Topics
Apparatus for Measurement in the Laboratory
Different physical quantities are measured using specific apparatus to ensure accuracy and reliability:
(a) Time – Stop-watches
- Used to measure time intervals accurately.
- Digital stop-watches give readings in seconds with decimal precision.
(b) Temperature – Thermometers
- Measure temperature of substances.
- Mercury-in-glass or alcohol thermometers: scale in °C.
- Digital thermometers provide faster and more accurate readings.
(c) Mass – Balances
- Used to measure the mass of solids, liquids, or powders.
- Electronic balances are commonly used with high accuracy (e.g. ±0.01 g).
(d) Volume – Burettes
- Used in titrations to deliver accurate volumes of liquids.
- Graduated in 0.1 cm³ divisions for precision.
(e) Volume – Volumetric Pipettes
- Used to transfer a fixed, precise volume of liquid (e.g. 25.0 cm³).
- More accurate than a measuring cylinder.
(f) Volume – Measuring Cylinders
- Used to measure approximate volumes of liquids.
- Less accurate than pipettes or burettes, but faster and easier to use.
(g) Volume of Gas – Gas Syringes
- Used to measure the volume of gas produced in reactions.
- Graduated markings allow readings in cm³.
Example :
Which apparatus would you use to measure exactly 25.0 cm³ of sodium hydroxide solution in a titration?
▶️ Answer/Explanation
Step 1: A measuring cylinder is not precise enough for titrations.
Step 2: A burette is for delivering variable volumes during titration.
Step 3: A volumetric pipette delivers a fixed, precise volume (25.0 cm³).
Final Answer: Use a volumetric pipette.
Key Terms in Solutions and Separation
(a) Solvent
- A solvent is a substance that dissolves a solute.
- Example: Water is a common solvent that dissolves salt or sugar.
(b) Solute
- A solute is a substance that is dissolved in a solvent.
- Example: Salt is the solute when it dissolves in water.
(c) Solution
- A solution is a mixture formed when one or more solutes are completely dissolved in a solvent.
- Solutions are homogeneous (same composition throughout).
- Example: Salt water is a solution of sodium chloride in water.
(d) Saturated Solution
- A saturated solution contains the maximum concentration of solute that can dissolve in the solvent at a specified temperature.
- Any extra solute added will remain undissolved.
- Example: At 25°C, if no more sugar dissolves in water, the solution is saturated.
(e) Residue
Residue is the solid substance that remains after evaporation, distillation, filtration, or similar processes.
- Example: Sand collected on filter paper after filtering a sand-water mixture.
(f) Filtrate
- Filtrate is the liquid or solution that passes through the filter during filtration.
- Example: Clear salt solution collected after filtering a sand-salt-water mixture.
Example :
When a mixture of sand and salt solution is filtered, name the residue and the filtrate.
▶️ Answer/Explanation
Step 1: The sand is trapped on the filter paper → this is the residue.
Step 2: The salt solution passes through the filter → this is the filtrate.
Final Answer: Residue = sand, Filtrate = salt solution.