Experimental design

Use the thermometer readings to fill the table for ammonium chloride.

May/June 2015

For questions $3$ to $7$ inclusive, put a tick (✓) in the box beside the right answer.

May/June 2015

For questions 3 to 7 inclusive, put a tick $(\checkmark)$ in the box next to the correct answer.

May/June 2015

A student is planning two experiments. Experiment 1: determine the concentration of a sodium hydroxide solution by titration using dilute hydrochloric acid Experiment 2: determine the rate of the reaction between pieces of calcium carbonate and dilute hydrochloric acid by recording the volume of gas released every minute A flask is already provided. What other apparatus is required?

May/June 2016

The laboratory contains the apparatus shown below. The diagrams illustrate three techniques for collecting gases.

May/June 2016

In this experiment, a student changes magnesium into magnesium oxide, MgO. A 0.36 g portion of magnesium is heated strongly for several minutes with the apparatus shown.

May/June 2017

A learner is given a bottle of tiny pieces of scrap iron. She must determine how pure the iron sample is. A small amount of the iron is put into a container that has already been weighed, and the container is then weighed again.

May/June 2017

Copper(II) sulfate crystals include water of crystallisation, which can be driven off by heating.

May/June 2017

A student needs to measure $28.2\text{ cm}^3$ of aqueous sodium bromide. Which apparatus should the student choose?

May/June 2021

The formula of magnesium oxide can be determined by using the fact that, when magnesium is heated, it reacts with oxygen and produces magnesium oxide. Which apparatus is used in this investigation?

May/June 2021

A scientist has to pour approximately $100\,\text{cm}^3$ of water into each of 50 large beakers. The scientist wants to complete the filling as quickly as possible. Which method should be used?

May/June 2022

A student is recording how the temperature changes in the reaction of $\text{HCl\,(aq)}$ with aqueous sodium hydroxide, $\text{NaOH\,(aq)}$. $\text{NaOH\,(aq)} + \text{HCl\,(aq)} \rightarrow \text{NaCl\,(aq)} + \text{H}_2\text{O\,(l)}$

May/June 2022

Baking powder helps cakes to expand. If water is mixed with baking powder, carbon dioxide gas is given off. The longer baking powder has been kept, the less carbon dioxide it gives off when water is added. Plan an investigation to determine which of two different samples of baking powder has been kept for a longer time. Your plan should include: • the apparatus needed • the method to use • the measurements to take • the variables to control • how to use the results to work out which sample has been kept for longer. You may draw a diagram to help answer the question.

May/June 2023

Baking soda helps bread rise. When baking soda is heated, it breaks down and carbon dioxide gas is given off. Baking soda also breaks down slowly while it is stored. The longer it is stored, the less carbon dioxide it gives off when heated. Plan an investigation to show which of two different samples of baking soda has been stored for longer. Your plan should include the use of common laboratory apparatus and the two samples of baking soda. No other chemicals are to be used. Your plan should include: - the apparatus needed - the method to use - the measurements to take - the variables to control - how to use the results to decide which sample has been stored for longer. You may draw a diagram to help you answer the question.

May/June 2023

The diagram displays four items of apparatus that are used to measure the volume of a liquid. Which item is always filled to the same mark?

May/June 2024

Barium carbonate breaks down on heating. The word equation for this reaction is shown. barium carbonate $\rightarrow$ barium oxide + carbon dioxide

May/June 2024

A student determines the amount of iron(II) ions in a solution by titration. The student: • uses a volumetric pipette to transfer $25.0\,\text{cm}^3$ of aqueous iron(II) sulfate into a conical flask • adds about $20\,\text{cm}^3$ of dilute sulfuric acid to the flask • slowly runs aqueous potassium manganate(VII) into the conical flask until the solution just becomes pink • carries out the titration again several times.

May/June 2024

Copper(II) carbonate is allowed to react with dilute sulfuric acid at room temperature. The reaction is represented by the word equation below. copper(II) carbonate + sulfuric acid $\rightarrow$ copper(II) sulfate + carbon dioxide + water Plan an experiment to find the volume of carbon dioxide produced when a known mass of copper(II) carbonate reacts completely with dilute sulfuric acid. Your plan should include common laboratory apparatus, dilute sulfuric acid and copper(II) carbonate. Do not use any other chemicals. Your plan should contain: • the apparatus required • the method to carry out and the measurements to record • ways to make the measured volume as accurate as possible. You may include a diagram to support your answer.

May/June 2024

A student finds the solubility of solid ammonium chloride in water at 60^{\circ}C. The student: step 1 places $100\text{ cm}^3$ of water in a beaker step 2 warms the water step 3 determines the mass of a weighing bottle that contains ammonium chloride step 4 puts some of this ammonium chloride into the water step 5 mixes the contents to make the solid dissolve step 6 repeats steps 4 and 5 until a small quantity of solid is still undissolved in the beaker step 7 measures the mass of the weighing bottle and the ammonium chloride left over step 8 works out the mass of ammonium chloride added to the water.

May/June 2025

A student carries out an investigation into how the solubility of solid potassium nitrate changes with temperature. The student: step 1 places 100 cm$^3$ of water in a beaker at room temperature step 2 finds the mass of the beaker containing the water step 3 puts some potassium nitrate into the water step 4 stirs the mixture until every part of the potassium nitrate has dissolved step 5 repeats steps 3 and 4 until a small amount of solid is still undissolved in the beaker step 6 finds the mass of the beaker containing the water and potassium nitrate step 7 repeats steps 1 to 6 with water at different temperatures step 8 works out the mass of potassium nitrate dissolved in the water at each temperature.

May/June 2025

A student is using the apparatus shown below to oxidise copper.

Oct/Nov 2015

The apparatus shown can be used to oxidise ethanol to ethanoic acid with acidified aqueous potassium manganate(VII). The diagram contains mistakes.

Oct/Nov 2017

On heating, magnesium combines with oxygen in the air to make magnesium oxide, a white powder. A student is investigating how the mass changes during this reaction. He is provided with a balance and three sets of apparatus, as shown. Which apparatus sets are appropriate for this investigation?

Oct/Nov 2018

State the names of the apparatus shown. Use the labels $P$ and $Q$.

Oct/Nov 2018

The diagram shows two items of laboratory apparatus, marked A and B.

Oct/Nov 2018

When aqueous lead(II) nitrate reacts with aqueous potassium iodide, lead(II) iodide is formed as a precipitate. $\text{Pb(NO}_3)_2(aq) + 2\text{KI}(aq) \rightarrow \text{PbI}_2(s) + 2\text{KNO}_3(aq)$

Oct/Nov 2018

Sulfur dioxide is produced by warming sodium sulfite with hydrochloric acid. It is an acidic gas, and sulfur dioxide is denser than air. Which arrangement of apparatus would be appropriate for making and collecting a dry sample of sulfur dioxide?

Oct/Nov 2019

A student has to measure $17.60\,\text{cm}^3$ of hydrochloric acid. The student can use the apparatus usually available in a school laboratory. Which item of equipment should be used to measure the $17.60\,\text{cm}^3$ of hydrochloric acid?

Oct/Nov 2020

A student uses the apparatus to produce ethanoic acid from ethanol.

Oct/Nov 2021

Which row gives the apparatus that is most suitable for the measurement stated?

Oct/Nov 2022

Which item of apparatus would be most appropriate for measuring exactly $37.00\ \text{cm}^3$ of aqueous ammonia?

Oct/Nov 2022

A student receives two bottles marked A and B, together with dilute hydrochloric acid. One bottle holds $1.00\,\text{g}$ of solid potassium carbonate, $\text{K}_2\text{CO}_3$. The other bottle contains $1.00\,\text{g}$ of solid potassium hydrogencarbonate, $\text{KHCO}_3$.

Oct/Nov 2022

A student is given two bottles, A and B, together with some water. One bottle contains $1.00\,\text{g}$ of solid potassium chloride, $\text{KCl}$. The other bottle contains $1.00\,\text{g}$ of solid calcium chloride, $\text{CaCl}_2$. Dissolving potassium chloride in water is endothermic. Dissolving calcium chloride in water is exothermic. Devise experiments, using the dissolving of the solids in water, to determine which compound is in each bottle and which compound gives the larger heat change per gram of solid.

Oct/Nov 2022

When sulfuric acid, $\text{H}_2\text{SO}_4$, is mixed with aqueous sodium hydroxide, $\text{NaOH}$, it is neutralised. $$\text{H}_2\text{SO}_4 + 2\text{NaOH} \rightarrow \text{Na}_2\text{SO}_4 + 2\text{H}_2\text{O}$$ This reaction gives out heat. P is $1.25\,\text{mol dm}^{-3}$ aqueous sodium hydroxide. Q is dilute sulfuric acid. A student is finding the concentration of sulfuric acid in Q. The student carries out six experiments. The student: Step 1 uses a volumetric pipette to place $25.0\,\text{cm}^3$ of P into a plastic cup. Step 2 uses a measuring cylinder to add $20\,\text{cm}^3$ of distilled water to the plastic cup. Step 3 stirs the contents of the cup with a thermometer and notes the temperature to the nearest $0.5\,^{\circ}\text{C}$. Step 4 uses a burette to add $5.0\,\text{cm}^3$ of Q to the plastic cup and stirs. Step 5 records the greatest temperature reached. Step 6 empties the plastic cup and washes it with water. Step 7 repeats steps 1-6 using five different volumes of distilled water and Q so that the total volume in the cup is always $50\,\text{cm}^3$. The student’s results are shown in Table 2.1.

Oct/Nov 2023

What apparatus is used to measure precisely $27.3\,\text{cm}^3$ of a liquid?

Oct/Nov 2024

Argentan is an alloy made up only of zinc, nickel and copper. Zinc and nickel both react with dilute hydrochloric acid, but copper does not react with dilute hydrochloric acid. Devise an investigation to determine the percentage by mass of copper in a powdered sample of argentan. Your plan must make use of common laboratory apparatus, argentan and dilute hydrochloric acid. No other chemicals may be used.

Oct/Nov 2024

Muntz metal is an alloy containing zinc and copper. Zinc reacts with dilute sulfuric acid, whereas copper does not react with dilute sulfuric acid.

Oct/Nov 2024

Which row is the correct one?

Oct/Nov 2025

Which statement is the correct one?

Oct/Nov 2025

Which of the following statements is correct?

Oct/Nov 2025

Which diagram represents a measuring cylinder?

Oct/Nov 2025

Which of the following statements is correct?

Oct/Nov 2025

Alcohols can act as fuels for heating water. Plan an experiment to find out whether methanol or ethanol gives out more thermal energy per gram when burned. In your plan, describe how an alcohol burner, as in Fig. 4.1, would be used to heat water. Use water, methanol, ethanol and ordinary laboratory apparatus only; do not use any other chemicals. Fig. 4.1 labels: alcohol burner, alcohol. Your plan should cover: the extra apparatus required; the procedure to follow and the measurements to record; how those measurements are then used to decide which alcohol releases more thermal energy per gram burned. You may include a diagram if that helps.

Oct/Nov 2025