Experimental work Question 9

Paper 3 Section A Experimental work Question 9

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Note that this question is HL only as it relates to 19.1 “Perform lab experiments that could include single replacement reactions in aqueous solutions.”

Manganese is above zinc in the activity series. The total electromotive force (EMF) produced by connecting a Zn(s)/Zn2+(aq) half-cell to a Mn(s)/Mn2+(aq) half-cell operating under standard conditions is 0.42 V.

(a) Draw a clearly labelled diagram showing the apparatus and chemicals you could use in a school laboratory to confirm this information Your diagram should also show the direction of flow of electrons in the external circuit. (Upload your answer as an image or as a pdf file). [3]
 

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(b) You are provided with a piece of cobalt and a molar aqueous solution of cobalt nitrate, Co(NO3)2. Describe how you could determine practically without using a voltmeter whether the standard electrode potential for the Co(s)/Co2+(aq) half-cell is more negative or more positive than either or both of the two half-cells used in (a). [2]
 

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(c) When a voltmeter is used the potential difference between a Co(s)/Co2+(aq) half-cell and a Mn(s)/Mn2+(aq) half-cell is found to be 0.90 V and the potential difference between a Co(s)/Co2+(aq) half-cell and a Zn(s)/Zn2+(aq) half-cell is found to be 0.48 V.
Determine the standard electrode potential of the Co(s)/Co2+(aq) half-cell using information given in Section 24 of the data booklet. [1]

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