11. Group 17
A section of Chemistry, 9701
Listing 10 of 617 questions
The diagram below shows an incomplete experimental set-up needed to measure the Ecell of a cell composed of the standard Cu2+/Cu electrode and an Ag+/Ag electrode. copper electrode solution A electrode B saturated solution of AgCl solid AgCl State the chemical composition of solution A, electrode B. Complete the diagram to show the whole experimental set-up. The above cell is not under standard conditions, because the [Ag+] in a saturated solution of AgCl is much less than 1.0 mol dm–3. The Eelectrode is related to [Ag+] by the following equation. equation 1 Eelectrode = E electrode + 0.06 log[Ag+] Use the Data Booklet to calculate the E cell if the cell was operating under standard conditions. E cell = V In the above experiment, the Ecell was measured at +0.17V. Calculate the value of Eelectrode for the Ag+/Ag electrode in this experiment. Use equation 1 to calculate [Ag+] in the saturated solution. [Ag+] = mol dm–3 o o o Write an expression for Ksp of silver sulfate, Ag2SO4, including units. Ksp = units Using a similar experimental set-up to that illustrated opposite, it is found that [Ag+] in a saturated solution of Ag2SO4 is 1.6 × 10–2 mol dm–3. Calculate the value of Ksp of silver sulfate. Ksp = Describe how the colours of the silver halides, and their relative solubilities in NH3, can be used to distinguish between solutions of the halide ions Cl –, Br – and I –. Describe and explain the trend in the solubilities of the sulfates of the elements in Group II.
9701_w12_qp_41
THEORY
2012
Paper 4, Variant 1
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The diagram below shows an incomplete experimental set-up needed to measure the Ecell of a cell composed of the standard Cu2+/Cu electrode and an Ag+/Ag electrode. copper electrode solution A electrode B saturated solution of AgCl solid AgCl State the chemical composition of solution A, electrode B. Complete the diagram to show the whole experimental set-up. The above cell is not under standard conditions, because the [Ag+] in a saturated solution of AgCl is much less than 1.0 mol dm–3. The Eelectrode is related to [Ag+] by the following equation. equation 1 Eelectrode = E electrode + 0.06 log[Ag+] Use the Data Booklet to calculate the E cell if the cell was operating under standard conditions. E cell = V In the above experiment, the Ecell was measured at +0.17V. Calculate the value of Eelectrode for the Ag+/Ag electrode in this experiment. Use equation 1 to calculate [Ag+] in the saturated solution. [Ag+] = mol dm–3 o o o Write an expression for Ksp of silver sulfate, Ag2SO4, including units. Ksp = units Using a similar experimental set-up to that illustrated opposite, it is found that [Ag+] in a saturated solution of Ag2SO4 is 1.6 × 10–2 mol dm–3. Calculate the value of Ksp of silver sulfate. Ksp = Describe how the colours of the silver halides, and their relative solubilities in NH3, can be used to distinguish between solutions of the halide ions Cl –, Br – and I –. Describe and explain the trend in the solubilities of the sulfates of the elements in Group II.
9701_w12_qp_42
THEORY
2012
Paper 4, Variant 2
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Write down what you would see, and write equations for the reactions that occur, when magnesium chloride, aluminium chloride and silicon tetrachloride are separately mixed with water. magnesium chloride aluminium chloride silicon tetrachloride Sodium chloride is traditionally added to a particular meat product. In response to the evidence that sodium chloride can lead to high blood pressure, the manufacturers have replaced the sodium chloride with a mixture of sodium and potassium chlorides. 100 g of the meat product usually contains about 2 g of the chloride mixture. A particular meat product contains 1.10 g of sodium chloride and 0.90 g potassium chloride in 100 g. Calculate the number of moles of chloride ions in 100 g of this meat product. The amount of chloride in the meat product can be found by titration with silver nitrate solution. Write the ionic equation, including state symbols, for the reaction between aqueous sodium chloride and aqueous silver nitrate. The chlorides from 100 g meat product are extracted into water and the solution made up to 1000 cm3 in a volumetric fl ask. A 10.0 cm3 portion of this solution is then titrated with 0.0200 mol dm–3 silver nitrate solution to precipitate the chloride. Calculate the volume of 0.0200 mol dm–3 silver nitrate solution that would be required if this titration were carried out on 100 g of the particular meat product described above. The iodination of benzene requires the presence of nitric acid. Using bond enthalpies from the Data Booklet, calculate the enthalpy change for the following reaction. + I2 + HI I → Nitric acid reacts with hydrogen iodide according to the following unbalanced equation. HI + HNO3 → I2 + N2O3 + H2O Balance this equation, and describe how the oxidation numbers of nitrogen and iodine have changed during the reaction. nitrogen iodine
9701_w12_qp_43
THEORY
2012
Paper 4, Variant 3
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617