Introduction In this practical you are going to do a series of experiments concerning electrochemistry. In part 1 you will learn to set up an electrochemical cell using copper and

nickel and how to measure the EMF of the cell. In parts 2 and 3 you will use a microscale experiment to investigate the reactivity series of four metals and the effect of concentration on cell potential. In part 4 you will use electrolysis to extract tin metal from a solution of tin chloride. Method During the experiment, record ALL observations. There is a table at the end of these instructions for you to use or prepare your own tables. Experiment 1: Preparation of a copper/nickel electrochemical cell. E = +0.34 V Cathode E° = -0.26 V anode Cu²+ (aq) + 2e →→ Cu(s) Ni2+ (aq) + 2e →→→ Ni(s) step o 1. Add 30 cm³ of the 0.1 moldm3 copper sulphate to a labelled 50 cm³ beaker and 30 cm³ 0.1 moldm³ nickel sulphate to another. Predict which metal will form the anode and which will form the cathode using the E° values given. Label the beakers accordingly. 2. Place the nickel metal strip in the beaker containing the nickel sulphate and the copper metal strip in the beaker containing the copper sulphate. First thing 3Soak a strip of filter paper in a saturated solution of potassium nitrate and then use this to connect the beakers as a salt bridge. 4. Connect the anodic cell to the negative terminal of the voltmeter and the anodic cell to the positive terminal. 5. Set the voltmeter to 20V and record the EMF of the cell. (2000 mV) - 6omv-62mv Experiment 2: Microscale Electrochemistry already calculated and made X Make 1 cm³ of 1 mol dm3 copper (II) sulphate solution. RMM copper (II) sulphate pentahydrate = 249.7 gmol-¹. You will need to calculate the mass required. The mass of copper sulphate will be quite small so weigh this carefully. 2. Fold your filter paper into quarters and cut out a portion to form a flower shape. See the diagram below. Cut on the dotted line "Flower shape" 3. Place your filter paper flower in a petri dish, fold any excess over the edge. 4. Use a pencil to label each petal with each of the four metals you will be testing: copper, zinc, nickel and magnesium. 5. Place a small square of the metal on the appropriate petal of the flower. 6. Add three drops of the appropriate 1.0 moldm-3 metal ion sulphate solution on to the petal around the edge corresponding piece of metal. Make sure the solution soaks into the filter paper. 7. Add enough potassium nitrate solution to the centre of the flower so it meets the dampened petals. - 20mV + 8. Place the positive probe of the voltmeter on the copper foil and the negative probe on the zinc. Measure and record the potential. Switch the probes and record the potential again. 1.39 му Ni 9. Repeat step 8 with the other metals combinations. e Produced in oxidation from anode Half cell combination = Negative Half cell black red = Positive Corp binathon Cu, Zn, Ni, Mg Zn 2n which metal which metal | E.cell is anode is cathode 41 уси Ni Mg мд CU Mg Zn cu 0.85 Ni Zn Ni си Voltmetre Cathode EMF (Mr) 0.85 0.75 1.39 0.60 0.16 anoole 0.06 Half-cell combination cozn Zn Ni MgNi чимд. CUNI CUMg repeat step 7 in EXP.2 Experiment 3: Effect of concentration 1. Prepare another filter paper flower and petri dish. 2. Fill in the dilution table below and prepare 1 cm³ (1000 μl) of 0.1 moldm-1 and 1 cm³ of 0.01 moldm3 copper sulphate solutions in the microtubes provided. Label the lids. Target concentration Volume H₂O (moldm-³) 0.1 Target concentration (moldm-³) 0.01 Volume H₂O 900 3. Use a pencil to write the different concentrations of copper sulphate solutions in each of the four petals. Label two petals 1.0 moldm-³. (10)(0.01) Volume 1.0 moldm³ CuSO4 4. Place a small square of copper on each petal. Add three drops of the appropriate concentration copper sulphate solution at the edge of each piece of metal. (1.0) (1.0) 1.0 (1.0) (0.1) 0.1 To.1 (0.01) 0.1 0.01 Volume 0.1 moldm3 CuSO4 5. Place at negative probe of the voltmeter on the copper on one of the 1.0 moldm ³ petals and the negative probe on the other. Measure and record the potential. 0.07 6. Measure and record the potential between the copper on the 1.0 moldm-³ petal and the diluted solutions. CUSO4 which metal which metal Concenentation is anode moldm3 is cathode 1.0 1.0 100 0.01 1.0 E. cell EMF (Mr) exfo 2000mV 0.02 0.49 0.13 080.22 Part 4 Electrolysis of tin (II) chloride 1. Add enough 1.0 moldm3 tin (II) chloride in hydrochloric acid to a petri dish to cover the base to a depth of a few mm 2. Using two steel paper clips create electrodes that are submerged in the acidified tin solution by bending them over the edge of the petri dish as per the diagram below. کیا 3. Place a damp litmus paper in the lid of the petri dish use this to cover the base. 4. Connect one paper clip to the negative terminal of a 9V battery and the other to the positive terminal using the connecting leads and crocodile clips provided. 5. Record your observations. Th metal chloride formed Metal Scent on the e Cathode clip - litmus-Paper bleached write half-reaction Writing up your report - In general, follow the instructions in the hand-out on writing laboratory reports. Your report must be written in Arial 12, at least 1.5 line spacing and left justified. 10 This report is worth 20% of your SF05 module mark You must include: A clear concise Aim - Summarise what you are aiming to find out in a couple of sentences