0620/61 · Oct/Nov 2023
Download PDFA student uses chromatography to analyse samples of three different dyes. The apparatus the student uses is shown in Fig. 1.1.
A spot of each dye is placed on the paper and some ethanol is poured into the beaker. Draw on Fig. 1.1: ● three spots (●) to show where the three dyes are placed on the paper at the start of the experiment ● a line to show the level of ethanol in the beaker at the start of the experiment.
During the experiment the ethanol moves up the paper. State when the student should remove the chromatography paper from the ethanol in the beaker.
Fig. 1.2 shows the result of the chromatography experiment. State what conclusions can be made from this result.
Copper(II) carbonate reacts with dilute acids to make carbon dioxide gas. Malachite is a mineral that contains copper(II) carbonate. A student investigates the rate of reaction between powdered malachite and dilute ethanoic acid at different temperatures. The student does six experiments. Experiment 1 ● Use a measuring cylinder to pour of dilute ethanoic acid into a conical flask. ● Warm the dilute ethanoic acid by about . ● Measure the temperature of the acid using a thermometer. ● Set the apparatus up as shown in Fig. 2.1. ● Remove the bung from the conical flask and add of powdered malachite to the conical flask, replace the bung and start a stop-clock. ● Record the time taken for of gas to be collected in the measuring cylinder. ● Empty the conical flask and rinse it with distilled water. Experiment 2 ● Repeat Experiment 1 but warm the dilute ethanoic acid by about . Experiment 3 ● Repeat Experiment 1 but warm the dilute ethanoic acid by about . Experiment 4 ● Repeat Experiment 1 but warm the dilute ethanoic acid by about . Experiment 5 ● Repeat Experiment 1 but warm the dilute ethanoic acid by about . Experiment 6 ● Repeat Experiment 1 but warm the dilute ethanoic acid by about .
Use the thermometer and stop-clock diagrams to complete Table 2.1.
Complete a suitable scale on the y-axis and plot the results from Experiments 1 to 6 on Fig. 2.2. Draw a line of best fit through your points.
The average rate of reaction in an experiment can be calculated using the equation shown. Use this equation to calculate the average rate of reaction in Experiment 6. Give the units for the rate you have calculated. average rate = .............................. units ..............................
Deduce in which experiment, 1, 2, 3, 4, 5 or 6, the rate of reaction is greatest.
Extend the line on your graph in Fig. 2.2. Deduce the time taken to collect of gas when the temperature of the ethanoic acid is . Show clearly on Fig. 2.2 how you worked out your answer. .............................. s
The of ethanoic acid used in each experiment is measured using a measuring cylinder. Measuring cylinders are available in the following sizes. Draw a circle around the size of measuring cylinder which would be most suitable to measure of ethanoic acid.
Most of the gas collected in the measuring cylinder is air rather than carbon dioxide. Explain why air is collected in the measuring cylinder.
Explain why this does not affect the accuracy of the results.
During each experiment the temperature of the acid decreases slowly. Give a reason why the temperature of the acid decreases and suggest a change to the apparatus used that would minimise the decrease in temperature. reason temperature decreases .................................................................................................. .................................................................................................................................................... change to apparatus .................................................................................................................. ....................................................................................................................................................
A student tests two substances: solid M and solid N. Tests on solid M Solid M is hydrated chromium(III) nitrate. Complete the expected observations.
The student places half of solid M in a boiling tube and heats it strongly. The student holds a piece of anhydrous cobalt(II) chloride paper at the mouth of the boiling tube. observations ....................................................................................................................... .......................................................................................................................................
The student inserts a glowing splint into the mouth of the boiling tube. The splint bursts into flames. Identify the gas given off by heating solid M which causes this result.
The student dissolves the remaining solid M in water to form solution M. The student adds aqueous sodium hydroxide dropwise and then in excess to solution M. observations adding dropwise ............................................................................................ observations in excess .......................................................................................................
The student adds a piece of aluminium foil to the product from (b)(i). The mixture is then warmed. The student tests for any gas produced. observations ....................................................................................................................... .............................................................................................................................................
Tests on solid N Table 3.1 shows the tests and the student’s observations for solid N. Describe how to carry out a flame test.
Identify solid N.
Greaseaway and Kitchenclean are two solutions used as household cleaners that contain aqueous ammonia. Plan an investigation to find which of the two household cleaners contains aqueous ammonia with the highest concentration. Assume that aqueous ammonia is the only alkali in the cleaners. Include in your plan: ● the method you will use ● how your results will be used to determine which household cleaner contains aqueous ammonia with the highest concentration. You are provided with common laboratory apparatus and chemicals.