5070/41 · May/June 2026
Download PDFFigure 1.1 shows the apparatus a student uses to investigate some dyes. A, B, C, D and M are dyes. The result for M is not shown.
Explain why the baseline must be above the solvent.
Suggest why there is only one spot for A and one spot for C but two spots for B on the chromatogram.
Suggest why dye D has not moved from the baseline.
The teacher says that a lid must be put on the beaker. Explain how using a lid improves the experiment.
M is a mixture of dyes A and C. Draw spots on Figure 1.1 to show what the chromatogram looks like for M.
A student investigates the effect of concentration on the rate of reaction between calcium carbonate and dilute hydrochloric acid. calcium carbonate + hydrochloric acid calcium chloride + water + carbon dioxide The student: • assembles the apparatus as shown in Figure 2.1 • records the mass • removes the cotton wool plug • adds of calcium carbonate to the conical flask • immediately replaces the cotton wool plug and starts a stop-watch • records in Table 2.1 the total mass of the conical flask and contents every 30 seconds.
State the mass of the conical flask and contents shown in Figure 2.1. mass .......................................................g
Calculate the total mass of the conical flask and contents at time 0 seconds. Write your answer in Table 2.1.
Explain why the total mass is the same at and .
Plot on the grid the total mass (-axis) against time (-axis). Label the axes.
Draw a curve of best fit.
Explain why the neck of the conical flask is not left open.
Explain why a cotton wool plug is used instead of a bung.
Suggest a source of error in the experiment.
Explain why the total mass decreases during the experiment.
Explain how the initial rate of reaction is calculated from the graph.
The concentration of the hydrochloric acid decreases during the reaction. State the relationship between the concentration of hydrochloric acid and the rate of this reaction. Explain how the graph shows this relationship. relationship ............................................................................................................................... explanation ...............................................................................................................................
A student investigates aqueous solution, W, and a green solid, Y. W contains an unsaturated carboxylic acid.
The student puts some W into a test-tube and adds aqueous bromine. Describe the observations the student makes.
The student adds a piece of zinc to W. A colourless gas and a colourless solution, X, are produced. Describe the observation the student makes that shows a gas is produced.
State the name of the gas produced. Describe the test and the positive result of the test used to identify this gas. name of gas ...................................................................................................................... test .................................................................................................................................... positive result ....................................................................................................................
The student tests the solution, X, produced in 3(b). The student adds a few drops of aqueous sodium hydroxide and then adds excess aqueous sodium hydroxide to X. Describe the observations the student makes. few drops of aqueous sodium hydroxide .................................................................................. excess aqueous sodium hydroxide ..........................................................................................
The student heats a dry sample of the green solid, Y. A white solid and a gas are formed. The gas turns anhydrous cobalt chloride paper pink. State the name of the gas.
The formation of this gas allows the student to make a conclusion about Y. Suggest the conclusion the student makes.
The student heats the white solid from 3(d) more strongly. A red-brown solid and a gas that turns acidified aqueous potassium manganate(VII) from purple to colourless are formed. State the name of this gas.
The student suggests that Y contains sulfate ions. Describe the test and the positive result that confirms this suggestion. test .................................................................................................................................... positive result ....................................................................................................................
The student adds a few drops of aqueous sodium hydroxide and then adds excess aqueous sodium hydroxide to an aqueous solution of Y. A green precipitate that is insoluble in excess is formed. State the cation present in Y.
The green precipitate turns brown near the surface when it is left to stand. Explain why the precipitate turns brown.
When salt is added to ice, the temperature of the mixture decreases. A student suggests that the greater the mass of salt that is mixed with ice the more the temperature of the mixture decreases. Plan an investigation to find out if the student is correct. Your plan should describe the use of common laboratory apparatus, crushed ice and salt. No other chemicals should be used. Your plan should include: • the apparatus needed • the method to use • the variables to control • how to use the results to decide whether the student is correct. You may draw a diagram to help answer the question.