IGCSE Science Paper 6 Practice Test

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• Which gas is produced when sulfite ions are treated with hydrochloric acid and warmed?
• What is the purpose of mineral wool in lab setups?
• When chromium(III) ions are treated with dilute sodium hydroxide, what is observed?
• In Benedict's test, brick red indicates what level of sugar concentration?
• Where do the electrons go after being released at the anode?
• Iron(III) ions treated with ammonia produce which observation?
• Which gas is evolved when a carbonate reacts with an acid in the insoluble solid reaction?
• How can you distinguish between hydrochloric acid and nitric acid?
• How can you check the purity of a collected solvent?
• In the cooling rate of water experiment, what data presentation is used to determine the cooling rate?
• Why should samples be taken from different parts of a field?
• Chromium(III) ions reacting with dilute sodium hydroxide yield what?
• What is a benefit of measuring 10 oscillations instead of a single oscillation?
• How can you distinguish between alkanes and alkenes using bromine water?
• What is a concentrated base?
• To confirm the presence of sulfate ions, which sequence is correct?
• Which statement about drying methods is true?
• What is a concentrated acid?
• When a delivery tube is used in an experiment and heat is removed, what precaution should you take?
• In a typical precipitation reaction, what is the state of the insoluble product?
• Why is grass ground with ethanol?
• What happens in the final step of the six-step preparation process?
• In electrolysis, which electrode is the negative electrode?
• What is a strong base?
• Blue cobalt chloride paper turning pink indicates the presence of what substance?
• What carries the current through the external circuit in an electrolysis setup?
• Which half-reaction occurs at the cathode when copper ions are reduced?
• In the copper test, the best four-mark observation is:
• What color precipitate forms when iodide ions are tested with acidified dilute nitric acid and silver nitrate?
• Copper(II) ions reacting with aqueous ammonia produce which result?
• What does the term 'excess reactants' imply about the reaction mixture?
• Blue cobalt(II) chloride paper changes to which color when exposed to water?
• What is the general role of the anode in electrolysis?
• Which of the following is given as an example of a salt with water of crystallisation?
• What is the third step in making crystals?
• In electrical experiments, which precaution addresses the offset in instrument readings?
• In electrolysis, the electrolyte must be in which form to conduct electricity?
• Which result appears to be inaccurate according to the observation tables and graphing instructions?
• What is the second step in making crystals?
• When a gas collection tube is inverted, which property is typical for the gas?
• Which device is used to condense steam back into water?
• Calcium ions treated with aqueous ammonia produce which observation?
• What is electrolysis?
• What is the recommended practice to prevent the meter from sticking during measurements?
• What happens to litmus paper when placed in sodium sulfate solution?
• How can you distinguish water and ethanol using cobalt chloride paper?
• In an electrolysis setup, which observation confirms that an electric current is passing through the solution?
• What is the purpose of a Liebig condenser?
• Copper(II) ions react with dilute sodium hydroxide to form what?
• What is the colour of rusty iron filings?
• How can you detect the point of crystallisation?
• What is the interval in a data set of readings?
• How could you know which reactant is in excess?
• Why is the experiment conducted in a fume cupboard?
• Which type of compound cannot be split into ions by electrolysis?
• In the insulation experiment, which result indicates the better insulator?
• What does decant mean in the context of separating a solid from a liquid?
• To detect nitrate ions, which procedure will produce ammonia when warmed?
• How do you check the purity of a collected solvent?
• Improvement made to calculating circumference by string method?
• What is observed when carbonate ions are treated with dilute acid?
• As the temperature increases, what happens to the rate of reaction according to collision theory?
• Which sulfate is typically insoluble in water according to the listed exceptions?
• In Benedict's test for reducing sugars, which color indicates the highest sugar concentration?
• Ammonium ions treated with sodium hydroxide produce which gas and observation?
• What is a recommended method to improve accuracy when collecting measurement data?
• Which statement best describes validity in an investigation?
• What is the general property of salts in terms of bonding?
• Which result indicates carbon dioxide extinguishes a lit splint?
• What is the effect of salty water on rusting?
• Carbonate ions treated with dilute acid produce which observation?
• Why should the solid be crushed before a reaction?
• In the ray box method, which factor is an identified inaccuracy?
• Which statement best defines the dependent variable in an experiment?
• Fractional distillation relies on differences in what property to separate liquids?
• What two things are required simultaneously for rusting?
• What happens when aluminum ions are treated with aqueous sodium hydroxide?
• After filtration, what is the next step in the six-step preparation process?
• When copper oxide is reacted with hydrogen, what is the colour change?
• How can you distinguish copper sulfate and copper carbonate?
• When testing Cr3+ with dilute sodium hydroxide, what happens to the precipitate when excess NaOH is added?
• What is the purpose of excess reactants?
• When handling lead bromide, which safety measures are appropriate?
• If a reagent is more concentrated, what happens to the volume needed?
• In the characteristic reaction method, if the insoluble solid is a metal reacting with an acid, what are the products?
• How does a strong acid behave in solution compared with a weak acid?
• Why are water baths recommended when heating flammable liquids such as alcohol?
• Calcium ions reacting with ammonia yield what?
• Sulphur dioxide gas can be identified by which reaction with potassium manganate(VII) solution?
• What is water of crystallisation?
• What precipitate forms when chloride ions are tested with acidified dilute nitric acid and silver nitrate?
• When zinc ions are treated with aqueous sodium hydroxide, what is observed?
• What does concentrated mean?
• What does concentrated mean in a solution?
• In the test for distinguishing copper sulfate from copper carbonate, which test indicates the presence of sulfate ions after acidifying with hydrochloric acid and adding barium chloride?
• During the electrolysis of water in alkaline solution, which gas is produced at the anode?
• During electrolysis, where do positive ions collect?
• Which result is considered inaccurate in a drawn graph context?
• How can you distinguish between chlorine and sodium chloride?
• Which statement best describes how cobalt chloride paper indicates the presence of water?
• When lead bromide is used, what safety precautions should be taken?
• What is necessary for rusting?
• What does saturated mean in relation to a solution at a constant temperature?
• What precipitate forms when bromide ions are tested with acidified dilute nitric acid and silver nitrate?
• Which description best defines repeatable measurements?
• In the titration steps, after the indicator changes color, what is done?
• Which gas would cause both limewater to turn milky and a glowing splint to be extinguished?
• Which observation shows oxygen supports combustion?
• What observation indicates the presence of chloride ions using a damp blue litmus test?
• What observation occurs when aluminum ions are treated with aqueous ammonia?
• If a measuring cylinder is used, how could you obtain more accurate results?
• What observation is seen when carbon dioxide is bubbled through limewater?
• To test for pure water physically, which property is checked?
• What is observed when iron(II) ions are treated with aqueous ammonia?
• Which gas is produced when sulfuric acid reacts with a carbonate?
• For electrolysis, state general observations.
• What happens to the resistance of a resistor when its temperature increases, according to the material?
• Chromium(III) ions reacting with aqueous ammonia yield what?
• Precautions taken in experiments about formation of images by a lens?
• During electrolysis, which statement correctly describes how the current in the electrolyte is carried?
• What is a strong base?
• Why is the experiment performed in a well-ventilated room?
• Observing condensation in the first row of heating tests indicates what about the solid?
• What happens when two soluble salts are mixed?
• Continuous variables have values (a quantity) that can be given a magnitude either by counting or by measuring.
• Which statement describes a typical observation when copper oxide is reduced by hydrogen?
• What type of error must be avoided by looking perpendicular to the ruler in readings?
• Which of the following could serve as an electrode material?
• What colour change occurs to hydrated copper sulfate upon heating?
• Which pH range describes a weak base?
• In the DCPIP test for vitamin C, what happens to DCPIP in the presence of vitamin C?
• What is a strong acid?
• In an electrolysis setup, what happens at the cathode?
• Before closing the circuit switch, which check should be performed?
• If a solid is hydrated, which term best describes its composition?
• What is the purpose of ice or cold water in a gas collection setup?
• Suggest why it is important to know the pH of soil.
• Categorical variables have labels such as names or types.
• What is the starting colour of Benedict's solution before heating?
• Which observations would correctly distinguish sulfuric acid from aqueous sodium sulfate when using a carbonate test, a metal test, and litmus?
• Which observation confirms the presence of sulfate ions when using the acidified barium nitrate test?
• Which statement describes a property of a pure solid substance?
• After a precipitate forms, how is it isolated?
• What is observed when iron(III) ions are treated with aqueous ammonia?
• In the copper test, what is the color of the initial precipitate?
• In a copper test that carries four marks, which description best describes the copper product?
• When using ethanol in the setup, what arrangement is best and why?
• Electrolysis splits an ionic compound into which components?
• Damp red litmus paper can be replaced with which indicator for pH testing?
• In an experiment for rusting, why might the water level rise?
• In experiments about heating, cooling, and insulation, which action improves accuracy?
• Heat loss could be reduced by:
• When the gas collecting tube is inverted during collection, which property is true of the gas?
• In a lens formation experiment, why should the object and lens be at the same height on the bench?
• Which observation occurs when iron(II) ions are treated with aqueous sodium hydroxide?
• Which precaution helps ensure reliable connections in circuits?
• Why is concentrated sulfuric acid not used to dry ammonia gas?
• What happens to a glowing splint in an environment containing carbon dioxide?
• The white precipitate formed in the sulfate test is which compound?
• What is the general purpose of a condenser in a distillation setup?
• Calcium ions reacting with sodium hydroxide yield what?
• In titration, what is the purpose of the indicator?
• Which action would minimize heating effects of a current in a circuit?
• What is the purpose of adding ice or cold water when collecting gas in this context?
• Zinc ions with sodium hydroxide yield which observation?
• Chloride ions show which observation when damp litmus paper is used?
• In the ethanol emulsion test for fats, what observation indicates fat is present?
• What is the safety risk when heating alcohol directly with a flame?
• What color does iodine solution produce if starch is present?
• In the copper test, what happens to the light blue precipitate when excess reagent is added?
• Addition of aqueous ammonia to copper(II) ions produces what?
• When copper oxide is reacted with hydrogen, what is the colour change?
• Which method is used to prepare soluble salts by neutralisation?
• A set of 21 readings equally spaced over a distance of 2 meters would have an interval of
• What are general observations in electrolysis?
• Which gas turns limewater milky when bubbled through it?
• What gas is produced when nitrate ions are treated with sodium hydroxide, aluminum foil and warm?
• Reduction occurs at which electrode?
• Which two tests are described for confirming carbon dioxide?
• Fractional distillation versus simple distillation relies on differences in boiling points. Which statement is true?
• Which procedure and observation confirms the presence of sulfate ions?
• What is the purpose of performing the experiment in a well-ventilated room?
• Which color change indicates the presence of water when using anhydrous copper(II) sulfate?
• A measurement is reproducible if the investigation is repeated by another person, or using different equipment or techniques, and the same results are obtained. Which statement best describes reproducibility?
• Which metal ion forms a white precipitate with sodium hydroxide that dissolves in excess sodium hydroxide?
• Which statement best describes precision in measurements?
• To minimize parallax error when reading a ruler, where should your eyes be?
• Suggest a suitable material for the electrodes.
• The true value is the value that would be obtained in an ideal measurement.
• What does saturated mean at constant temperature?
• What must a valid conclusion be based on?
• Which ion yields a white precipitate when treated with acidified aqueous barium nitrate?
• Aluminum ions with sodium hydroxide produce which observation?
• Which gas is produced when a metal reacts with sulfuric acid?
• What is a concentrated base?
• Which improvement helps increase accuracy of ray diagrams?
• Aluminum ions treated with aqueous ammonia produce which observation?
• In chromatography, what is the role of a locating agent?
• Salt compounds are formed from an acid by replacing which part with a metal?
• What is the general role of the cathode in electrolysis?
• What does decant mean?
• Which gas is produced at the anode when chloride ions are present in the electrolyte during electrolysis?
• What color change occurs for hydrated copper sulfate upon heating?
• During the sulfur dioxide test with acidified potassium permanganate, what is observed to happen to the purple permanganate solution?
• Beaker insulation reduces heat loss in heating experiments. Which option best reflects this?
• Which statement about a weak base’s ionisation is true?
• What is the colour of rusty iron filings?
• Which observation confirms carbon dioxide is present when bubbled through limewater?
• In the two-insulator experiment, which outcome indicates the better insulator?
• Which method involves extracting salt from underground rock deposits?
• What does 'excess' mean in a chemical reaction?
• What happens to the rate of reaction when the temperature increases and particles gain kinetic energy?
• Which ions lose electrons at the anode?
• What does electrolysis do to an ionic compound?
• Which method would NOT speed up drying?
• Which statement correctly describes a strong base in comparison with a weak base?
• What is the purpose of a Liebig condenser?
• What do you use to crush?
• Zinc ions with aqueous ammonia produce which observation?
• Which of the following is an example of a categorical variable?
• Which pH value is neutral?
• Iron(III) ions treated with sodium hydroxide produce what precipitate and its solubility in excess?
• What is the primary hazard that justifies covering the apparatus when using ethanol?
• Which pH range describes a strong acid?
• Excess reactant is defined as
• In an experiment using ethanol, what is a better apparatus arrangement and why?
• Which scenario describes measurements that are precise but not accurate?
• Biuret reagent contains which components?
• The solution commonly known as lime water is?
• When drying crystals, which method is recommended to minimize water loss and preserve crystal integrity?
• What should you do with the current when you are not taking a measurement?
• Which reagent is used to confirm the presence of sulfate ions by forming a white precipitate?
• A valid conclusion is supported by valid data, obtained from an appropriate experimental design and sound reasoning.
• In the centre of mass experiment with a lamina, how should you view the string to determine balance?
• Why is concentrated sulfuric acid not used to dry ammonia?
• Which acid is used in the sulfite test to release carbon dioxide?
• The half-reaction 2H+ + 2e- → H2 occurs at which electrode?
• What is a locating agent?
• Which pH range corresponds to a strong base?
• What is a strong acid?
• Which statement about water's physical properties is correct?
• What is an excess reactant?
• Repeats and averaging improve which aspect of measurement?
• Iron(II) ions treated with aqueous ammonia yield which observation?
• In the Biuret test, what color appears if protein is present after adding Biuret reagent?
• In chromatography, if a pen were used to draw the origin line instead of a pencil, what would likely happen?
• How can you detect the point of crystallisation?
• Bubbling which gas through limewater produces a milky suspension due to calcium carbonate formation?
• Why should resistance be measured with low currents and voltages?
• In the ray experiment, which of the following can cause angle i not to equal angle r?
• How can you make crystals?
• How can you distinguish copper sulfate from copper carbonate?
• What substance is deposited at the cathode when copper ions are reduced in solution?
• Uncertainty is the interval within which the true value can be expected to lie with a given level of confidence. For example, 20°C ± 2°C at 95% confidence.
• Which action reduces heating when taking current readings?
• What is necessary for rusting to occur?
• Which statement best describes the copper test result that yields four marks?
• Which statement correctly describes a weak acid’s pH range?
• Which gas is evolved when a metal carbonate reacts with sulfuric acid?
• In electrolysis, electrons flow from the battery to which electrode?
• Sulfite ions react with hydrochloric acid and gentle warming to evolve which gas?
• In the DCPIP test, if vitamin C is absent, what color is observed?
• Why is it useful to measure soil pH in farming?
• If condensation is observed in the first row of a heating test, what does this indicate about the solid?
• Which method uses brine solutions to obtain salt from deposits?
• How can you distinguish hydrochloric acid from nitric acid using a silver nitrate test?
• Which reagent(s) produce a color change indicating the presence of water?
• What is the effect on rusting when pure oxygen is used?
• If a sample has no reducing sugar, Benedict's test colour remains?
• Which general equation represents the neutralisation of a dilute acid with an alkali to form a metal salt and water?
• Where do positive ions gain electrons during electrolysis?
• What is the purpose of knowing the pH of soil?
• Salt compounds are generally
• What is the last step in the crystal-making process?
• What color does phenolphthalein indicate in an acidic solution?
• If the power of a heater is doubled and the heating time is kept the same, what happens to the heat energy Q supplied?
• Why is the experiment conducted in a fume cupboard?
• After repeating the titration with the noted acid volume and the same alkali volume but without the indicator, what is the next step?
• In the pin method, which issues contribute to inaccuracies?
• Why should samples be taken from different parts of a field?
• Which of the following describes a physical test for water?
• How can you distinguish between sulphuric acid and aqueous sodium sulphate?
• Which ion is detected by a qualitative test that forms a white precipitate when acidified aqueous barium nitrate is added?
• Why are excess reactants used?
• Suggest a suitable material for the electrodes.
• How does the vertical position of the center of mass affect an object's stability?
• How is speed of sound in air calculated in the described experiment?
• Why might crystals be dried with filter paper instead of heating?
• How can you distinguish between alkanes and alkenes?
• Which instrument provides greater accuracy for delivering precise volumes in a lab setting?
• Which gas is described as pale green with a choking smell and is poisonous?
• What is observed when copper(II) ions are treated with dilute sodium hydroxide?
• How is a salt formed from an acid and a metal according to the given description?
• Which practice reduces errors when testing field soil?
• In the characteristic reaction method, if the insoluble solid is a base (metal oxide or alkali) reacting with acid, what is formed?
• Which statement about drying crystals is true?
• To increase stability, which changes are suggested?
• Which statement best describes a sketch graph?
• Which observation is typical of electrolysis of an aqueous solution?
• What is the range of a data set?
• What is the first step in the six steps of preparation for soluble salts via the characteristic method?
• Fractional distillation separates which of the following?
• What does heating condensation observation reliably indicate about water content in the solid?
• The external circuit in electrolysis is used to carry what?
• Iodide ions treated with acidified silver nitrate yield which color precipitate?
• What is a prediction in scientific terms?
• When a delivery tube is involved in an experiment and heat is removed, what precaution should be taken?
• Why is grass ground with ethanol?
• Which property would you test to assess solvent purity by comparing to known values?
• What is litmus paper's response to sulfuric acid?
• How can you distinguish chlorine gas from sodium chloride using litmus paper?
• Chloride ions treated with acidified silver nitrate yield what precipitate?
• What happens when iron(III) ions are treated with aqueous sodium hydroxide?
• Precautions for circuit readings of I and V so that readings are accurate?
• During electrolysis, the anode is the positive electrode.
• Which statement best defines the independent variable in an experiment?
• Why is a pencil used to draw the origin line in chromatography?
• Validity refers to the suitability of the investigative procedure to answer the question asked.
• In the characteristic reaction method, if the insoluble solid is carbonate reacting with acid, what is formed?
• The half-reaction Al3+ + 3e- → Al occurs at which electrode?
• What is the reason for using a lid when working with ethanol?
• What is the pH of a neutral solution?
• Using Snell's law, which expression gives the refractive index when light moves from air into glass?
• Name the method used for preparing insoluble salts.
• Iron(II) ions with sodium hydroxide produce which precipitate?
• What happens to negative ions at the anode?
• Fractional distillation is used to separate mixtures based on differences in
• What is the difference between a strong acid and a weak acid in terms of pH ranges?
• What is formed at the cathode during electrolysis?
• To locate the center of mass of a plane lamina in the described method, what is done?
• Non-metals (except hydrogen) are attracted to which electrode?
• When drawing the image formed by a lens, the image is...
• In the oxidation–reduction test, what color change occurs when sulfur dioxide reduces acidified potassium permanganate solution?
• What instrument provides more accurate measurements than a measuring cylinder?
• Which formula represents specific heat capacity given heat energy Q, mass m, and temperature change ΔT?
• In experiments about springs and stretching, which of the following is a variable?
• When a hydrated solid is heated to remove water of crystallization, what is the likely outcome?
• In describing rate of reactions, which phrase is essential?
• In a reaction, what happens if more solute is added to a saturated solution at a fixed temperature?
• When zinc ions are treated with aqueous ammonia, what is observed?
• What is the result of testing ammonia with damp red litmus paper?
• How can you tell which reactant is in excess at the end of a reaction?
• What is a concentrated acid?
• What is the effect on using pure oxygen on rusting?
• Which statement describes ammonia gas?
• Reproducibility is demonstrated when repeated experiments yield the same conclusions even if done by different people or with different equipment.
• Which statement describes a dilute base?
• Which half-reaction occurs at the anode for chloride ions to form chlorine gas?
• An inert electrode used in electrolysis is usually made from which materials?
• Biuret reagent original colour before reaction is?
• What happens when hydrogen gas is burned with a lit splint?
• What is the chemical formula of the ion that is detected by the sulfate test?
• During electrolysis, positive ions in the liquid are reduced at the cathode to form what?
• Which gas is harmful and can cause difficulty breathing upon exposure?
• In chromatography, why is a locating agent used when amino acids are studied?
• According to the law of reflection, what is the relationship between the angle of incidence i and the angle of reflection r?
• During the six-step process, when crystals are seen on the glass rod, what should you do?
• How can you distinguish between water and ethanol?
• What is the purpose of lagging or cloth when heating chemical substances?
• What does it mean to decant a liquid and solid mixture?
• During electrolysis, where do negative ions collect?
• Precipitation can be used in industry for which purpose?
• During electrolysis, which of the following indicates that current is flowing?
• After filtering, how are traces of soluble salt removed from the precipitate?
• When current is applied to an electrolyte, what happens to a positive ion?
• A solution with pH 1 is considered what type of acid strength?
• What is the purpose of mineral wool?
• Which variable is deliberately changed by the researcher in an experiment?
• What happens to the volume of a reagent if it is more concentrated?
• Why is a pencil used to draw the origin line in chromatography experiments?
• Which statement best describes a continuous variable?
• Which reagent is used to test for sulfate ions in solution?
• Which method would NOT speed up drying?
• Adding aqueous ammonia to chromium(III) ions yields what?
• Variables are physical, chemical or biological quantities of characteristics.
• Which gas is produced in the nitrate test when using sodium hydroxide and aluminium foil and warming?
• Why are water baths used when heating alcohol?
• A control variable is a value which may affect the outcome and therefore must be kept constant or monitored.
• Why do ionic compounds conduct electricity when molten or dissolved, but not as solids?
• What does a precise, sharp boiling point indicate about a solvent's purity?
• When using an ammeter/voltmeter, what range strategy is recommended to maximize resolution?
• Copper(II) sulfate pentahydrate contains how many water molecules per formula unit?
• Why should the solid be crushed before reacting?
• The anode is the site of which process?
• Which of the following statements correctly identifies the sulfate ion?
• In the sulfur dioxide test, a potassium permanganate solution in acidic conditions changes from purple to colorless. Which gas causes this change?
• What color does phenolphthalein indicate in an alkaline solution?
• Which statement describes the basic purpose of electrolysis?
• How do you check if a rule is vertical?
• How can you make crystals?
• Which color change indicates water when using anhydrous copper sulfate?
• What gas is produced when ammonium ions are treated with aqueous sodium hydroxide and warmed?
• What color does methyl orange indicate in an acidic solution?
• Why would crystals be dried on filter paper rather than heated?
• When calcium ions are treated with aqueous sodium hydroxide, which observation is produced?
• What color does methyl orange indicate in an alkaline solution?
• In chemical quantities, the term excess refers to
• In rate of reactions, which phrase is essential to include?
• What do you use to crush?