Experimental Techniques and Chemical Analysis
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Measurement and apparatus
SubtopicMeasurement and apparatus under Experimental Techniques and Chemical Analysis for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Which piece of equipment is used to place a hot crucible on while it cools?
A.Wire gauze
B.Heat-proof mat
C.Filter paper
D.Glass slide
- 2.
What is the function of the 'meniscus' when measuring liquids?
A.It is a type of glassware
B.It is the curved upper surface of a liquid column
C.It is a cleaning tool
D.It is a chemical indicator
- 3.
Which instrument would you use to measure exactly for a reaction to change color?
A.Clock
B.Stopwatch
C.Wristwatch
D.Metronome
- 4.
Which of these is a measure of the amount of substance in the SI system?
A.Gram
B.Liter
C.Mole
D.Pascal
- 5.
Which piece of equipment is used to keep a substance dry or to dry a substance that has been filtered?
A.Desiccator
B.Condenser
C.Volumetric flask
D.Separating funnel
- 6.
A student needs to heat a flammable liquid. Which heating method is the safest?
A.Directly over a Bunsen burner flame
B.Using a heating mantle or a water bath
C.Over a spirit burner
D.Using a blowtorch
- 7.
What is the primary advantage of using a pH probe and meter over Universal Indicator solution?
A.It is cheaper to use.
B.It provides a numerical value and is more precise.
C.It can be used with solids.
D.It does not require calibration.
- 8.
A student is using a calorimeter to find the enthalpy of combustion of methanol. Which of the following errors would lead to a value of that is less exothermic than the literature value?
A.Ignoring the heat capacity of the copper calorimeter.
B.Some of the methanol evaporates before the wick is lit.
C.The distance between the flame and the calorimeter was too small.
D.The student failed to stir the water throughout the experiment.
- 9.
In a titration, a student found the average titre to be . The burette has an uncertainty of for each reading. Which of the following represents the titre with its absolute uncertainty?
A.24.35 ± 0.05 cm3
B.24.35 ± 0.10 cm3
C.24.4 ± 0.1 cm3
D.24.35 ± 0.025 cm3
- 10.
A student wants to distinguish between and solutions. Which single reagent would be most effective for this purpose?
A.Dilute sulfuric acid
B.Aqueous potassium iodide
C.Aqueous sodium hydroxide
D.Aqueous ammonia
Download the worksheet for Experimental Techniques and Chemical Analysis - Measurement and apparatus to practice offline. It includes additional chapter-level practice questions.
Chromatography
SubtopicChromatography under Experimental Techniques and Chemical Analysis for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
Why is chromatography paper often dried before being sprayed with a locating agent?
A.To make the paper easier to handle
B.To prevent the locating agent from reacting with the solvent
C.To ensure the value doesn't change
D.Locating agents only work on wet paper
- 2.
If a substance has an value of 0.8, where is it located on the chromatogram?
A.Near the baseline
B.Near the solvent front
C.Exactly in the middle
D.It has not moved at all
- 3.
Which of these is a qualitative use of chromatography?
A.Determining the exact mass of a component
B.Identifying the presence of a specific dye in a food sample
C.Measuring the total volume of a mixture
D.Calculating the percentage yield of a reaction
- 4.
What would happen if the baseline was drawn too low and the solvent level was above it?
A.The spots would move faster
B.The values would all become 1.0
C.The samples would wash off into the solvent in the tank
D.The paper would catch fire
- 5.
In chromatography, what happens if the components of a mixture do NOT dissolve in the mobile phase at all?
A.They will remain at the baseline
B.They will move to the solvent front immediately
C.They will evaporate into the beaker
D.They will react with the paper and change color
- 6.
Which of the following techniques is commonly used to visualize spots on a chromatogram that are not naturally colored?
A.Ninhydrin spray
B.Dipping the paper in ink
C.Heating the paper with a Bunsen burner
D.Washing the paper with soap
- 7.
What is the primary function of the 'column' in a Gas Chromatograph?
A.To provide a surface for the separation of the mixture's components
B.To heat the sample to its boiling point
C.To store the carrier gas under high pressure
D.To collect the components after they have been separated
- 8.
In GC-MS, the components separated by the gas chromatograph are passed into a mass spectrometer. What information does the mass spectrometer primarily provide to identify a peak?
A.The mass-to-charge () ratios of the molecular ion and its fragments
B.The exact boiling point of the component
C.The total amount of the substance in the original mixture
D.The optical rotation of the substance
- 9.
Which factor has the least effect on the value of a substance in TLC?
A.The total distance the solvent front travels
B.The polarity of the mobile phase
C.The chemical nature of the stationary phase
D.The temperature at which the chromatography is performed
- 10.
Two substances have values of 0.30 and 0.32. To improve their separation on a TLC plate, which of the following would be most effective?
A.Changing the solvent to one that provides better selectivity for the two compounds
B.Applying more of the mixture to the baseline
C.Using a shorter plate to speed up the process
D.Increasing the temperature of the laboratory
Download the worksheet for Experimental Techniques and Chemical Analysis - Chromatography to practice offline. It includes additional chapter-level practice questions.
Separation and purification
SubtopicSeparation and purification under Experimental Techniques and Chemical Analysis for Grade 12 IGCSE.
Preview questions (no answers)
- 1.
A student finds that a sample of sulfur melts between and . What does this indicate about the sample?
A.The sample is pure
B.The sample is a single element
C.The sample is impure
D.The thermometer is broken
- 2.
Which property allows centrifugation to separate a mixture?
A.Differences in boiling points
B.Differences in magnetic susceptibility
C.Differences in densities of the components
D.Differences in chemical reactivity
- 3.
To obtain pure water from seawater, which process is most suitable?
A.Filtration
B.Simple distillation
C.Crystallization
D.Magnetic separation
- 4.
Which of the following statements about chromatography is true?
A.A pure substance will always move to the top of the paper
B.The Rf value of a substance is constant for a specific solvent and temperature
C.Chromatography can only be used for colored substances
D.The stationary phase must always be a liquid
- 5.
Which of the following describes the correct procedure for testing the purity of a sample of benzoic acid?
A.Measure its mass and volume to find density
B.Dissolve it in water and check the pH
C.Determine its melting point and compare it to the data book value
D.Perform a flame test to see the color produced
- 6.
Why is vacuum filtration (suction filtration) often preferred over gravity filtration in a synthesis laboratory?
A.It yields larger crystals
B.It is much faster and leaves the solid drier
C.It does not require filter paper
D.It automatically purifies the filtrate
- 7.
A mixture of four dyes is analyzed using paper chromatography. Dye X moves , Dye Y moves , Dye Z moves , and the solvent front moves . Which dye has an value of ?
A.Dye X
B.Dye Y
C.Dye Z
D.None of the dyes
- 8.
In the context of chromatography, what does a large value (close to 1.0) indicate about the substance's interaction with the phases?
A.The substance has a high affinity for the stationary phase.
B.The substance is very soluble in the mobile phase and has little interaction with the stationary phase.
C.The substance is highly polar and the solvent is non-polar.
D.The substance is too heavy to move quickly.
- 9.
A student is asked to purify a sample of naphthalene contaminated with common salt. Which of the following is the most direct method?
A.Dissolve in water and filter.
B.Heat the mixture and collect the vapor on a cold surface.
C.Perform fractional distillation at .
D.Use a separating funnel with water and oil.
- 10.
During a filtration process, 'filtrate' is defined as:
A.The solid trapped on the filter paper.
B.The liquid that passes through the filter paper.
C.The mixture of solid and liquid before filtration.
D.The solvent used to wash the solid.
Download the worksheet for Experimental Techniques and Chemical Analysis - Separation and purification to practice offline. It includes additional chapter-level practice questions.