• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Introduction to titration of copper.

Extracts from this document...


INTRODUCTION Copper was discovered by chance over 11,000 years ago and today remains one of the most versatile metals on earth1. It is for this reason that it remains invaluable to mankind in a variety of applications from power transmission to micro- electronics. Copper is generally found as the di-valent cation, copper (II) or mono-valent ion, copper (I). At low concentrations, copper is an essential element but is toxic at high levels2 especially in water as it poses serious environmental and human health hazards. Industries involved in metal processing must therefore pre treat and/or detoxify the metal rich effluents before discharging them into the environment3 . As well as removing water pollution, economic benefits ensue from this process, due to the high cost of copper on the World markets. The following techniques can therefore be used to detect the presence of copper ions in water or solutions: TITRATION METHOD It involves a reduction-oxidation titration. Copper(II) ions react with excess iodide ions forming a copper (II) iodide precipitate and molecular iodine. 2Cu2+(aq) + 4I-(aq) 2CuI(s) + I2(aq) The iodine is then titrated against a standard solution of sodium thiosulphate in the presence of a starch indicator. I2 (aq) + 2S2O32-(aq) 2I-(aq) + S4O62-(aq) An alternative to this would be the titration of copper (II) ions against a solution of EDTA using Fast Sulphon F as an indicator. ...read more.


If in solution form, collect on absorbent material and store as a hazardous waste. MAKING UP OF SOLUTIONS To make up 1 litre of a molar solution, the relative molecular mass(RMM) of the solute is to be dissolved in a litre of distilled water. A standard volumetric flask is used. The solute is dissolved in a beaker of water to ensure that it is easily soluble. Using a funnel (so as to avoid spillage), the solution formed is added to the volumetric flask. The empty beaker should be rinsed out with distilled water so as to ensure that all of the dissolved solution has gone into the flask. This is done as it ensures that the concentration is the one required rather than a weaker one. When filling up the volumetric flask, the bottom of the meniscus should touch the line on the neck of the flask. The last cm3 must be added using a dropping pippette as this increases accuracy. Once the exact amount of water is in the volumetric flask, shaking of the solution is necessary so as to ensure that the entire solid is dissolved. Copper Sulfate I am making up 1 litre of a 0.05 molar solution for the colorimetric method. Copper Sulfate has a relative molecular mass of 249.68g. Therefore, in order to make up 1litre of 0.05M, I will have to dissolve 249.68g x 0.05 = 12.48g in a litre of distilled water. ...read more.


1.5cm x 1.5cm Filter paper strips, 2cm x 15cm Copper wire with alligator clips at each end Voltmeter Emery paper Canvas gloves Distilled water 200 cm3 1M Sodium sulfate 200cm3 1M Copper (II) sulfate 100cm3 1M Sodium Sulfate Method: The metal strips were polished using emery paper, rinsed with distilled water and then dried. This was done to ensure that the metal surfaces were free from any oxides that may have formed thereby providing a clean surface for reactions. The copper(II) sulfate, sodium sulfate and distilled water were placed in their own burettes (these are used as they allow the quantity of the solutions to be measured accurately). A funnel was used to ensure that there was no spillage. The volumes in the burettes were then set to 50cm3 by letting any excess solution out through the bottom and into a beaker. This was done until the bottom of the meniscus was laying on the 50cm3 line. The standard run used 50cm3 of copper (II) sulfate and 50cm3 of zinc sulfate. 1. Measure out 50cm3 of copper (II) sulfate into one of the 150cm3 beakers. 2. Dip a copper strip into the solution and attach a crocodile clip to it. This forms the copper half cell. 3. Measure out 50cm3 of zinc sulfate into another beaker, dip a zinc strip into it and attach the other crocodile clip to it. This forms the zinc half cell. 4. 5. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Aqueous Chemistry section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Aqueous Chemistry essays

  1. How much Iron (II) in 100 grams of Spinach Oleracea?

    Risk control strategy (precautions) Lab coat and goggles essential at all times. Keep the room well ventilated at all times. Keep the lid on the bottle unless in immediate use. Spillage If in crystalline form, transfer the spillage to a container of water, stir to dissolve and run to waste with plenty of water.

  2. Titration with a primary standard.

    If I had measured 50 cm3 with the same measuring cylinder, the error would have been 0.5/50 x 100 = 1% so the bigger the reading the smaller the percentage error. If I use a big measuring cylinder the graduations may be every 2 cm3.

  1. Free essay

    Investigation of aqueous electrolytic cells.For this experiment, we are to test an aqueous solution, ...

    Controlled variable: temperature, distance of carbon stick, length of carbon stick, type of cathode and anode metal, time of running led with constant current, volume or depth of emersion of electrodes. These are all the controlled variables, because they all need a certain amount or distance in order to keep

  2. making copper

    The solution should now be coloured blue. 4. Weigh out about 2 g of zinc filings of zinc powder. 5. Add the zinc to the copper sulphate solution. Stir the mixture. You will see solid copper forming. 6. After 5 minutes, allow the solid to settle.

  1. Investigating the Effects of Increasing Copper Sulphate Solution Concentrations on the Germination of Cress ...

    If each batch suffer from the same changes as a result of being in the same environment then the results are still statistically viable. I will keep them away from the classroom doors and windows. Putting them in an isolated corner means they will all be under the same temperature

  2. Ammonia - The Structure of Ammonia.

    Mechanism: H H H3N: C - Br � H3N+ - C :Br - H H H Reactions of aqua ions with aqueous ammonia An aqueous solution of ammonia is alkaline because of the presence of OH- ions. The addition of ammonia solution to a solution of a transition metal ion

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work