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

hydrated copper sulphate

Extracts from this document...

Introduction

Analysis Experiment 1 Time (minutes) Mass of crystals, crucible + lid (g) 0 23.36 5 22.59 10 22.41 15 22.41 20 22.41 Mass of crucible + lid = 20.82 g Mass of hydrated CuSO4 = 23.36 - 20.82 = 2.54 g Mass of anhydrous CuSO4 = 22.41 - 20.82 = 1.59 g Mass of water = 2.54 - 1.59 = 0.95 g % of water by mass = (0.95/2.54) x 100 = 37.401575 = 37.4 % (3.s.f) Mr of H2O = 18 No. of moles in 2.54g of H2O = 0.95/18 = 0.05278 moles No. of moles in 1g of H2O = 0.05278/2.54 = 0.020778652 moles Experiment 2 Mass of hydrated CuSO4 used = 5.83g Titre Volume (cm3) 1 23.5 2 25.0 (anomalous) 3 24.1 Average titre = (23.5+24.1)/2 = 23.80 cm3 Volume of S2O32- = 23.80 cm3 Concentration of S2O3 = 0.1 mol dm-3 Moles of S2O32- in 25ml = (0.1 x 23.80) / 1000 = 0.00238 moles Moles of S2O32- in 250ml = 10 x 0.00238 = 0.02380 moles To find the number of moles of Cu 2+, we need to see what ratio the Cu 2+ and S2O32- react in: They react in a 1:1 molar ratio. ...read more.

Middle

= +/- 0.24317723 % = +/- 0.2432 (4sf) Total % error in experiment 2: Burette: +/- 100 x [(0.5 x 0.1)/ 23.5] = +/- 0.212765957% +/- 100 x [(0.5 x 0.1)/ 25.0] = +/- 0.200000000% +/- 100 x [(0.5 x 0.1)/ 24.1] = +/- 0.207468879% Mass of crystals: +/- 100 x [(0.5 x 0.01)/5.83] = +/- 0.08576329331 % Pipette: +/- 100 x [(0.5 x 0.06)/25] = +/- 0.12 % +/- 100 x [(0.5 x 0.06)/25] = +/- 0.12 % +/- 100 x [(0.5 x 0.06)/25] = +/- 0.12 % (Combined) = +/- 1.065998129 = +/- 1.066% (4.s.f) In conclusion it appears that in both experiments 1 and 2, the percentage errors are relatively small which shows that my experiments were fairly reliable and accurate. The values for % error give a clear indication as to which experiment was more accurate, its apparent that experiment 1 was a lot more accurate than experiment 2 purely because its percentage error was +/- 0.2432 % which is sufficiently less than that of experiment 2 with +/- 1.066 % error. In experiment 1 the weighing scale gave values to 2 decimal places; however the burette was correct to only 1 decimal place. ...read more.

Conclusion

Most significant error in measurement and modification > From both experiments, the apparatus with the least % accuracy was the burette. It had errors up to +/- 0.212765957% which is the largest error out of all the equipment. This error can be minimised by using a burette with a smaller diameter. This allows the meniscus to be seen easily compared to that with a larger diameter. By doing so a more accurate result is gained, hence a more accurate reading of the volume of solution in the burette is obtained and so the results are more reliable. > Another modification is to use a burette with a much smaller scale. by using a scale which is more accurate than 0.1ml would allow for a more accurate reading of volume during titration. This effectively would allow for more accurate calculations and therefore results of higher accuracy. > A burette which has a much narrower tip should be used. This is allows fewer drops to be added in a given time, in effect colour changes can be spotted more accurately thus preventing an excess amount (which is not required) added. This prevention allows for more accurate results, therefore a more accurate and reliable experiment. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Organic 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 AS and A Level Organic Chemistry essays

  1. Thermal Decomposition of Copper Carbonate

    Protect against physical damage. Isolate from incompatible substances Whatever cannot be saved for recovery or recycling should be managed in an appropriate and approved waste disposal facility Copper (I) oxide [Cu2O(s)] 1.62x103moles Low reactivity. Release of toxic gases during decomposition.

  2. Find the enthalpy change of combustion of a number of alcohol's' so that you ...

    The calorimeter did not have a lid on it, which may have caused water to evapourate from it. This in turn reduces the mass of water and affects the value for the amount of water absorbed by the water, which then has an impact on the enthalpy change of combustion value, worked out.

  1. Comparing the enthalpy changes of combustion of different alcohols

    This means that in my experiment, the value of the enthalpy change of combustion of Methanol is 16.2% of what I have calculated it to be. Therefore the percentage errors that I have calculated for my experiment simply cannot account for this loss.

  2. The aim of this experiment is to investigate the enthalpy change of combustion for ...

    The lowest value I found was 720KJ/mol and the highest value was 805KJ/mol. That is a difference of 85KJ/mol. This show how difficult it is to accurately measure the strength of the hydrogen bonds between the molecules. In my plan I said that I was going to investigate whether the

  1. Enzyme catalysed decomposition of hydrogen peroxide

    because change in pH affects the ionic and hydrogen bonding in an enzyme and so alters it shape. Each enzyme has an optimum pH at which its active site best fits the substrate. Variation either side of pH results in denaturation of the enzyme and a slower rate of reaction.

  2. Determination of the formula of Hydrated Iron (II) Sulphate crystals

    of KMnO4 used to oxidise the Fe2+ ions, add the three titres together that are within 0.10cm� difference of each other and divide by three: Average titre:= (21.55 + 21.65 + 21.60)/ 3 = 21.60cm� Therefore, it requires an average volume of 21.60cm� of 0.01 mol dm-� KMnO4 to oxidise

  1. Aim: To determine how the concentration of each species in a reaction affects the ...

    being disturbed during the experiment * Ensure that equipment containing liquids, e.g. conical flasks, are well away from the edges of the table - in order to prevent the smashing of glassware * Being as careful as possible when handling chemicals - in order to avoid the spilling of chemicals

  2. IDENTIFICATION OF AN ORGANIC UNKNOWN

    Risk assessment before carrying out the test for aldehyde and ketone: Procedure / Chemical Risk Precaution Information derived from Silver ions Corrosive: causes burns. Solutions are very dangerous to the eyes and blacken the skin. Ingestion can cause internal damage.

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