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4.1 Acids

4.1 Acids

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Question 48

A student uses the following method to prepare a pure, dry specimen of the insoluble salt, lead(II) iodide ( $PbI_2$ ):

Measure 40 cm³ of lead(II) nitrate solution into a beaker.
Add a few drops of potassium iodide solution until a bright yellow precipitate is observed.
Allow the yellow precipitate to settle to the bottom of the beaker.
Carefully pour off (decant) the liquid from the top of the beaker.
Use a spatula to scrape the wet yellow solid directly onto a piece of paper to dry in the air.

Explain two improvements that should be made to this method to increase both the amount (yield) and the purity of the lead(II) iodide obtained.

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Markscheme

4.1 Acids Questions

GCSE
Chemistry
4.1 Acids

276 exam-style questions on Edexcel GCSE Chemistry 4.1 Acids, covering 4.1.1 Acids, alkalis and the pH scale, 4.1.2 Hydrogen ion concentration and pH, 4.1.3 Dilute and concentrated, weak and strong acids, 4.1.4 Bases, alkalis and the reactions of acids, 4.1.5 Chemical tests for hydrogen and carbon dioxide, 4.1.6 Neutralisation as a reaction of acids with bases, 4.1.7 Preparing soluble salts, and 4.1.8 Solubility rules and preparing insoluble salts. Each one has a worked solution and a mark scheme showing where the marks go.

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