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

Investigation to Identify the Formula of Hydrated Copper Sulphate and in doing so Find what x represents in the Formula CuSO4xH2O

Extracts from this document...

Introduction

Science Coursework: Investigation to Identify the Formula of Hydrated Copper Sulphate and in doing so Find what x represents in the Formula CuSO4�xH2O Name: Matthew Dobson Partner: Jamie Barton? Date(s) Conducted: 23/04/05 - 06/05/05 Topic: Chemistry - Moles and Empirical Formulas Experiment: The Degree of Hydration of Copper (II) Sulfate, CuSO4 � xH2O Aim: I plan to investigate the formula of Hydrated Copper Sulphate and, more importantly, what x stands for in the formula (CuSO4.xH2O). This will tell me how many molecules of water surround each molecule of Copper Sulphate. To do this I plan to work out the amount of water a set mass of Hydrated Copper Sulphate loses when it becomes anhydrous. I will work this out by measuring the difference in mass between the two states. And thus ascertain the degree of hydration. I predict that because it is hydrated copper sulphate and it is blue that it will contain water of crystallization surrounding the copper sulphate. The number of water molecules per copper sulphate molecule should fall somewhere between 1 and 5 as 1:5 is the largest ratio of copper sulphate to water this molecule can contain. Apparatus: MATERIALS: Hydrated copper (II) sulphate GENERAL: * * Heatproof mat, * Tripod, * Bunsen burner, * Pipe clay triangle, * Crucible, * Metal tongs, * Glass mixing rod, * Spatula, * Electronic-Balance SAFETY: Lab coat and safety glasses to be worn at all times and care to be taken when handling hot objects. Method: 1. Set up apparatus as shown in the diagram. ...read more.

Middle

- m(CuSO4) = 2.034 - 1.267 m(xH2O) = 0.767g ? 0.008g Solving to find "x" in (CuSO4 � xH2O) is now a simple matter of deducing the amount in moles of each compound, and finding the simplest integer ratio between CuSO4 and H2O. See: CuSO4 xH2O 1.267g ? 0.004g 0.767g ? 0.008g Using the formula: n = m/M, where n = moles, m = mass of sample, and M = relative atomic mass of compound n(CuSO4) = 1.267g/[63.55 + 32.06 + 4(16.00)] = 1.267/159.61 mol n(CuSO4) ? 0.00794 mol ? 2.5x10-5 mol n(H2O) = 0.767g/[2(1.01) + 16.00] = 0.767/18.02 mol n(H2O) ? 0.0426 mol ? 4.4x10-4 mol The ratio can now be easily determined: CuSO4 : H2O n(CuSO4)/ n(CuSO4) : n(H2O)/n(CuSO4) (1.267/159.61)/( 1.267/159.61) mol : (0.767/18.02)/(1.267/159.61) mol ? 0.00794/0.00794 mol : ? 0.0426mol/0.00794mol 1 : ? 5.36 So both the exact and the approximate ratio have been determined. However, presumably due to experimental errors the ratio is, of course, not a perfect integer. This can be dealt with in two ways: a) the ratio of 1 : ? 5.36 can be rounded to a ratio of 1 : 5 (which gives the formula of the hydrate as 5H2O) - but since 5.36 does not closely approximate 5.00, this is not an appropriate assumption. b) Alternately, a smaller rounding gives a ratio of 1 : 5.4 and this ratio can be easily multiplied to give an integer ratio as such: 5 x (1 : 5.4) ...read more.

Conclusion

It is likely that a culmination of these errors - with an emphasis on burning the sample - resulted in a degree of imprecision in these results. Regardless, the results were still quite conclusive. Improvements: Several aspects of this experiment could be developed to yield more accurate and precise results. The key improvement to this experiment would probably be to decrease the intensity with which flame is applied to the crucible. This would be to reduce the possibility of overheating, and increase the period of time spent dehydrating the sample to ensure a slower, more thorough (i.e. ensuring that most of the sample is anhydrous) and less intense dehydration. This improvement would allow a more thorough development of the sample, and more frequent processing on the scales. Another main improvement that could be implemented had the equipment been available would be to completely automate the experiment to remove the degree of human error. This would involve using very accurate robotic machines to precisely measure the amount of copper sulphate used and the mass of everything. It would also heat it for the exact amount of time to prevent burning (oxidization) or to not be fully dehydrated. In addition to this, either repetition of the experiment to obtain a broader spread of results or a collation of class results may have yielded more accurate results, as the mean of the results would probably have given a ratio for hydrated copper (II) sulfate much closer the accepted literature value of 1 : 5, or CuSO4 � 5H2O. Matthew Dobson Matthew Dobson 01/05/2007 Mr Robertson Chemistry pg1 ...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 Classifying Materials 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 Classifying Materials essays

  1. Determine the formula of the hydrate in hydrated copper (II) sulfate empirically, i.e. to ...

    0.002 3rd 9.292 Olive green becomes very distinct during heating 9.291 Powder is without a trace of original blue colour, now tinged a grey-olive green ? 0.002 Collating, Interpreting and Analysing Results: Known Values Mass of Crucible: 8.024g ? 0.002g Mass of Crucible and CuSO4 � xH2O: 10.058g ?

  2. An investigation into the water of crystallisation present in Hydrated Magnesium Sulphate

    This experiment will then be repeated. Fair Testing To make this a fair test, it is important that all the variables are kept constant apart from the heating of the substance to evaporate water. Also before measuring the mass of any of the objects, it is important to check the

  1. Determine BaCl2.2 H2O -Gravimetric Analysis Lab

    - 28.38 � 0.01g (Mass of Crucible, Lid and Heated Barium Chloride after 1st heating) = 0.27 � 0.02g (Mass of water removed from Barium Chloride on 1st Heating) Mass of Water Removed from Barium Chloride on 2nd Heating: 28.65 � 0.01g (Mass of Crucible, Lid and Barium Chloride Sample)

  2. Investigating the Factors Affecting the Temperature Change Between Zinc and Copper Sulphate

    If a larger mass of zinc was used during the experiment, there will be no reaction - there is no more copper sulphate solution to react with, and so, no more heat energy is given out. If a smaller mass than 1.3g of zinc is added, there will be some

  1. Free essay

    Periodic table

    People with haemophilia bleed longer because their blood does not clot well - can be treated with medicine - however they may suffer from internal bleeding in joints ==> painful arthritis. Gene Technology Gene Technology is the technology to take a single gene from a plant or animal cell and

  2. Chemistry Coursework. Aim: To find out if the thickness of plastic bags is ...

    * Have the clamp stand at the same height. Although this is not necessary, it could affect the overall results, if only by a small margin. This is because the gravity being exerted on the strip and masses will differ in accordance to height.

  1. Our experiment consisted of two samples of water containing unknown substances, and our objective ...

    Making sure the nozzle in the side of the Bunsen burner is fully closed, turn the tap on and, using a lighted splint, ignite the gas to a safety flame. 4. Slide the metal piece on the nozzle around slightly so it's about half open.

  2. Gold. For thousands of years, gold has been regarded as the finest and ...

    which means that the results from the process have numerical values, and are just observations. This increases accuracy greatly as numbers are more meaningful in this case than words, since the exact purity is very important in today's world and there is no room for error.

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