CHEMISTRY Higher Tier Paper 1 2020

This question is about silver iodide. Silver iodide is produced in the reaction between silver nitrate solution and sodium iodide solution. The equation for the reaction is: AgNO3(aq) + NaI(aq) → AgI(s) + NaNO3(aq) box . A student investigated the law of conservation of mass. This is the method used. 1. Pour silver nitrate solution into a beaker labelled A. 2. Pour sodium iodide solution into a beaker labelled B. 3. Measure the masses of both beakers and their contents. 4. Pour the solution from beaker B into beaker A. 5. Measure the masses of both beakers and their contents again. Table 3 shows the student’s results. Table 3 Mass before mixing in g Mass after mixing in g Beaker A and contents 78.26 108.22 Beaker B and contents 78.50 48.54 Explain how the results demonstrate the law of conservation of mass. You should use data from Table 3 in your answer. [2 marks] . Suggest how the student could separate the insoluble silver iodide from the mixture at the end of the reaction. box [1 mark] The student purified the separated silver iodide. This is the method used. 1. Rinse the silver iodide with distilled water. 2. Warm the silver iodide. . Suggest one impurity that was removed by rinsing with water. [1 mark] . Suggest why the student warmed the silver iodide. [1 mark] Question 3 continues on the next page