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

Back Titration Lab Report. In my experiment, I hoped to find the amount of calcium carbonate in some mineral limestone using the back titration method

Extracts from this document...

Introduction

Back Titration Lab Report Aim: Determining the percentage purity of calcium carbonate in a sample of limestone. Introduction: In my experiment, I hoped to find the amount of calcium carbonate in some mineral limestone using the back titration method The equation of the reaction is as follows: 2HCl + CaCO3 CaCl2 + CO2 + H2O As not all the acid will be used up in the above reaction, I plan to obtain the amount of acid not used up and consequently the amount of calcium carbonate in the limestone, by titrating it with known sodium hydroxide solution. The equation of the reaction is as follows: HCl + NaOH NaCl + H2O Apparatus: The equipment and reagents that I used are as follows: 250 cm3 beaker Electronic balance (± 0.01 g) ...read more.

Middle

I repeated the procedure to obtain 3 sets of readings and will take the average value as my result. Data processing and presentation: With all the above processes being done, I wrote down the values which I obtained in the raw data table below. Raw data Raw Data Measure Volume of acid used / cm3 (± 0.05 cm3) 1 41.6 2 41.4 3 41.5 I then processed my data to find the average volume of acid used. Vavg = V1+V2+V3 3 Vavg = 41.6 + 41.4 + 3 Vavg = 41.5 (± 0.05 cm3) Now I used the various formulas related to the mole concept to find the amount of calcium carbonate in the sample of limestone. The equations of the reactions are as follows: 1) 2HCl + CaCO3 CaCl2 + CO2 + H2O 2) ...read more.

Conclusion

2 = 4.075 x 10-3 moles Mass of CaCO3 in 1.5g of limestone = Moles x RMM (RMM of CaCO3 = 100) = 4.075 x 10-3 x 100 = 0.41g Percentage purity of calcium carbonate = 0.41 x 100 1.5 = 27.3 ± 0.35 % Conclusion: A possible source of error in this experiment is the determination of the end-point, which is characterised by the solution just turning orange. This is because a slightly greater volume of acid may have been used than required to produce the pink colour. To try to reduce the effects of this error I would like to carry out a large number of titrations and their average used in the calculation. Another possible way to reduce error is by using more accurate measuring instruments like a more precise burette so as to reduce the uncertainty of the measurements. ?? ?? ?? ?? ...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

Here's what a teacher thought of this essay

4 star(s)

This is a four star piece of work with excellent scientific knowledge of molar calculations and demonstrated great skill in their work. A clear, concise piece of work but they could have put more into the introduction and conclusion.

Marked by teacher Patricia McHugh 01/12/2012

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. Marked by a teacher

    Chemistry Investigation on neutralisation reaction.

    5 star(s)

    Heat of reaction = Mass x specific heat capacity x temperature change We assume that 25ml of solution has a mass of 25g. 25g x 4200J/kg0C x (29.83-20.13) =0.025kg x 4200J/kg0C x (29.83-20.13) =0.025kg x 4200J/kg0C x 9.70C =1018.5J for 25ml of 2 moles/dm3 hydrochloric acid.

  2. Marked by a teacher

    To investigate the effect of temperature on the rate of reaction

    4 star(s)

    0 0 0 40 81 76 79 79 66 63 64 64 53 56 58 56 44 45 46 45 21 20 23 21 8 9 8 8.3 4 6 5 5 1 2 1 1.3 50 90 87 89 89 75 73 76 75 64 65 64 64 54

  1. Free essay

    Rate of reaction

    3 star(s)

    I chose concentration because it allows me to investigate any concentration and therefore there is no limit to my range. I have chosen to investigate from 0.125 M up to 2 M at regular interval testing so it would be easier to assess if there are any proportional patterns.

  2. Marked by a teacher

    Determine the solubility product of calcium hydroxide

    3 star(s)

    Ans: When Ksp increases, the hydroxides are more soluble, the [OH-] becomes greater, the pH increases while the pOH decreases. DISCUSSION Since a saturated solution of Calcium Hydroxide is a sparingly salt that obeys the Law of Chemical Equilibrium. Therefore we can say that the solubility equilibrium of Calcium Hydroxide CaOH is : Ca (OH)

  1. Find out which antacid tablet works most efficiently using a technique called titration.

    moles of active ingredient = 2 x 0.0007619047619 = 0.00152380954 moles (11dp) Concentration of HCl to be used = 1M (1mole per dm3) Predicted volume of HCl needed = moles/concentration = 0.00152380954/1 = 0.00152380954dm3 = 1.52380954cm3 (8dp) Total predicted volume of HCl needed = 1.52380954 + 1.619047619 + 10.44 =

  2. Indirect determination of enthalpy change of decomposition of sodium hydrogen carbonate by thermochemical measurement ...

    = = +992.75J I then calculated the mole fraction of NaHCO3 used: n= Mass / Mr : Mr NaHCO3 = 84 Moles NaHCO3 = mass NaHCO3 = 3.203 = 0.038 Mr NaHCO3 84 Finally, I calculated the molar ?H (the heat of solution per mole of solute)

  1. Aspirin Investigation

    Alternative Synthesis Routes for the Production of Aspirin Method One (Source: Organic Experiments (5th Edition) Louis F. Fieser and Ken Williamson) This method of obtaining aspirin demonstrates the effect of four acetylating catalysts: two bases, sodium acetate and pyridine; a Lewis acid, boron trifluoride; and a mineral acid, sulphuric acid.

  2. Investigating the effects of varying pH levels on the germination of cress seeds

    I will attempt to control the remaining variables by keeping all of the samples in the same room, in the same area, with closed windows and doors. In the event of any of these variables (bar volume and concentration) changing beyond my control, I do not believe that it will

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