• 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...


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.


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.


1 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

    To determine the amount of ammonia in a sample of household cleaning product, 'cloudy ...

    5 star(s)

    The reason for this difference may be because the bottle of ammonia used in the experiment had been opened for a long time and thus many of the ammonia had 'escaped' into the air as fumes. Discussion: 1. It is important to have the correct rinsing procedures as it minimises the chances of error.

  2. Marked by a teacher


    4 star(s)

    Aspirin is a medicine commonly found in households around the world. It also is one of the least expensive and most useful drugs in the market. A Chemist named Felix Hoffmann first synthesized aspirin, otherwise known as acetylsalicylic acid, in 1897 from salicylic acid.

  1. Marked by a teacher

    Determine the solubility product of calcium hydroxide

    3 star(s)

    A decrease in the solubility of the salt (NaOH) solution is the effect of adding a common ion into the solution. The concentration will influence the reaction of equilibrium. 5) What effect, if any, does the Hydroxide ion concentration have on the solubility of calcium hydroxide in water?

  2. Titration Experiment

    Readings Results 1st reading 23.5 cm3 2nd reading 23.3 cm3 3rd reading 23.2 cm3 Average reading 23.3 cm3 Calculations Reading 1= 21.9 cm3 reading 2=22.1 cm3 reading=21.8cm3 Calculation of average titre: 21.9+22.1+21.8= 65.8 cm3 65.8 3 Volume of alkali used=25 cm3 Concentration of alkali used=0.1 mol Volume of acid used=

  1. To investigate the rate of reaction between different concentrations of hydrochloric acid with metal ...

    thus, the best amount of calcium carbonate to use, is 1.00 grams, this is because, it gives, a nice, quick experiment, but it is not too slow to do or too fast to time. The 2.00 grams experiments were getting a bit too slow.

  2. A Colorimetric Determination of Manganese In Steel

    irritant to the skin as is phosphoric acid, acidified potassium periodate and propanone. The Results. Finding the filter with the best absorbance. Wavelength of filter (nm) Absorbance 430 0.55 470 0.70 490 1.20 520 1.40 550 1.35 580 0.90 600 0.45 700 0.25 From the results it can be seen that the best filter had a wavelength of 520nm.

  1. Indigestion Tablets Investigation

    hydrochloric Acid + Magnesium --> Magnesium + water + carbon carbonate chloride dioxide Sodium bicarbonate is also know as sodium hydrocarbonate "Sodium hydrocarbonate is used in baking. The carbon dioxide gas it gives off when heated makes dough rise. It is also used as an antacid to relieve indigestion" (page 169)

  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