Chemistry · May / June 2023 · Paper 62 · Question 4
0620
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The question as text
A metal polish is a mixture of four substances. The properties of these substances are shown in Table 4.1. Table 4.1 name of substance solubility in water reaction with dilute nitric acid propanol soluble dissolves ethanoic acid soluble dissolves iron(III) oxide insoluble reacts when warmed to form a soluble salt silicon(IV) oxide insoluble no reaction Plan an experiment to find the percentage by mass of silicon(IV) oxide in the mixture. Your plan should include how you will calculate the percentage of silicon(IV) oxide in the mixture. You are provided with a sample of the metal polish, dilute nitric acid and common laboratory apparatus. [6]
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any 6 from:
MP1 stated / known mass of polish / weigh polish
MP2 add nitric acid
MP3 nitric acid and polish / solid combined in a suitable container
MP4 warm / heat (polish and acid / water)
MP5 filter (wash) and dry residue / solid
MP6 find the mass of the silicon(IV) oxide
MP7 percentage = (mass of SiO2 / mass of polish) × 100
max 6
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