• 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...


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.


= +/- 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.


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

    I feel could have been a build up of soot on the under side of the calorimeter which meant that the carbon was not fully combusting in carbon dioxide and would not have been accounted for in the results. Reasons such as a draught in the room caused by movements of the other pupils could have had some effect etc.

  2. The aim of this experiment is to produce Aspirin. This is an estrification in ...

    Actual weight of salicylic acid = 4.0029g Total % error = 1.25125% 1.25125% of 4.0029g = 0.0500 (0.0125125 x 4.0029) 0.0500 + 4.0029 = 4.0529 4.0029 - 0.0500 = 3.9529 So therefore the confidence limit lies between 4.0529 + 3.9529 Forward titration (pure aspirin)

  1. Enzyme catalysed decomposition of hydrogen peroxide

    will be kept constant at 20Vol this is because as the substrate concentration increases (at constant enzyme concentration) the rate of reaction increases until it reaches a maximum rate (V max). This is because there will be less number of free active sites and more number of substrate molecules to

  2. Comprehensive and Detailed Chemistry notes

    them -- Recently, chemical instruments indicate that atmospheric concentrations of these oxides are decreasing at a steady rate explain the formation and effects of acid rain Sulfur and nitrogen compounds pollute the atmosphere. Rain water reacts with these acidic oxides and becomes quite acidic due to the high solubility of these gases in water.


    Ingestion can cause internal damage. If swallowed, wash out mouth and drink a glass or two of water. Seek medical attention as soon as possible. If inhaled, remove victim and put where there's fresh air. If chemical gets into eyes, wash off with plenty of water and seek medical help.

  2. Comparing the enthalpy changes of combustion of different alcohols

    Therefore alcohols will give out less energy in their combustion than an alkane of the same carbon number. Because of these facts, I can predict a number of things. Firstly, I can say that, per mole, larger molecules will release more energy in their combustion than shorter molecules.

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