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

Thermal Decomposition of Calcium Carbonate

Extracts from this document...

Introduction

Introduction Calcium Carbonate, CaCO3 decomposes with heat, to produce Calcium Oxide, CaO and Carbon Dioxide, CO2. CaCO3(s) CaO(s) + CO2(g) The object of this practical exercise is to determine the enthalpy change for this reaction by an indirect method based on Hess' Law. Results Table Experiment 1: Mass of CaCO3 and weighing bottle 3.47g Mass of empty weighing bottle 1.08g Mass of CaCO3 used 2.39g Temperature of acid initially 22oC Temperature of solution after mixing 24oC Temperature change during reaction 2oC Experiment 2: Mass of CaO and weighing bottle 2.58g Mass of empty weighing bottle 1.00g Mass of CaO used 1.58g Temperature of acid initially 22oC Temperature of solution after mixing 27oC Temperature change during reaction 5oC Calculating the Enthalpy Change Experiment 1: Calculating the H1 for the reaction between CaCO3 and HCl Using the formula: Density = Mass Volume , We can work out the mass of liquid (HCl) Mass = Density x volume = 2.0 x 0.05 = 0.1 grams Using the calculated mass, we can work out the total energy transfer using the formula: Energy Transfer = Mass of Liquid x specific heat capacity x change in temperature = 0.1 x 4.2 x (24-22) = - 0.84 J From the results table, we can see that the temperature increased from 22oC to 24oC, so we can deduce that the reaction was EXOTHERMIC. ...read more.

Middle

However, after looking over my method, I can see a few minor errors that could have altered the results given. In the experiment, one or two minor misjudgements could have been made; although such mistakes will not have been sufficient enough to change the results. The top pan balance, used for weighing out the calcium carbonate and calcium oxide, is a very accurate method of measuring quantities. However, top pan balances only measure to two decimal places. On a balance like this the second decimal place is not reliable, giving an error of �0.01g. CaCO3 (0.01/2.39) x 100 = 0.42%% chance of error CaO (0.01/ 1.58) x 100 = 0.63%% chance of error. To overcome this problem, it is important to weigh out the solids to the required weigh; take them off the scale; place them back on the scale and check the weight. If the two weights are very different from each other, it may be best to weigh the solids again. However the calculated chances of errors are not high enough to cause any concern for the accuracy of my results. One of the major concerns about the accuracy of my results was the ability of the thermometer to read the temperature to the required level. ...read more.

Conclusion

This, in turn, will distort the calculated enthalpy changes, and they will be incorrect. It is known that beakers can be not be very accurate, as the measurements are in 50cm3 graduations; I decided to use a measuring cylinder to measure the acid, which range from 0cm3 to 250cm3, with 1.0cm3 graduations. Therefore the measurements of volume will be rounded to the nearest 1.0cm3, giving a degree of inaccuracy. When measuring the acid out, I need to make sure the meniscus is at the bottom of the measurement line. All these four errors are significant to the experiment, as they can all contribute to an increase or decrease of the temperature of the experiment. The most significant error in the method was the fact that the temperature is not correctly identified by the thermometer. I believe this to be the most important factor, as this is the main way of detecting the temperature. If the temperature is slightly out, the end result will be slightly out. Overall I think that experiment 1; involving CaCO3 was the more reliable of the two experiments. The main reason behind this decision was the fact that the reaction is very quick, leaving less time for any heat to be lost to the environment and its surroundings. ?? ?? ?? ?? Chemistry Coursework - Assessed Practical ...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 Inorganic 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 Inorganic Chemistry essays

  1. Peer reviewed

    Determining the concentration of acid in a given solution

    5 star(s)

    all of the sodium carbonate molecules were in the solution at the bottom. I could calculate the moles so sodium carbonate in the conical flask and calculate the moles of sulfuric acid from that value. If not as much sulfuric acid was needed to neutralise the alkali as not all

  2. Peer reviewed

    Deducing the quantity of acid in a solution

    5 star(s)

    acid in Hazcard 98A "Methyl orange" in http://www.proscitech.com.au/catalogue/msds/c118.pdf and Hazcard 32 "Sodium carbonate" in: http://www.jtbaker.com/msds/englishhtml/s3242.htm and Hazcard 95A "Concentrations of solutions" in Daniels A., Johnston L.

  1. effects Concentration and Temperature on the Rate of Reaction

    This gradient can be measured and the activation enthalpy can be worked out. Making Molar Solutions (5) Molar (M) solutions are based on the number of moles of chemical in 1 litre of solution.

  2. Lab report Determination of Enthalpy Change of Neutralization

    Secondary, there must be some heat loss to the surroundings. It will cause the enthalpy change of the solution smaller than the expected. Then the molar enthalpy change of the solutions also decrease, as a result, the enthalpy change of hydration of calcium carbonate will be smaller than the expected.

  1. Titration Coursework

    I will pour the sulphuric acid using a funnel. I will then burette with sulphuric acid as long as it's on zero or below that. I will then run the burette tap until the sulphuric acid comes to the bottom of the burette. I will then take the initial reading from the burette.

  2. Free essay

    Determination of the Heat of Formation of Calcium and Calcium Carbonate

    Initial temperature /? 26.00? Temperature rise /? 28.50? Discussion: 4. Ca(s) + 2H+(aq) --> Ca2+(aq) + H2(g) 5. Heat of formation of calcium chloride will be evolved. 6. E = mc?T = (100)(4.2)(28.5) = 11970 J ? The heat evolved in the reaction between calcium and acid is 11.970 kJ.

  1. Scientific Practical Techniques

    2) Check the pH of the four unknown liquids 1) For this investigation I used four unknown buffer solution a solution the pH of which does not change significantly, pH meter and a stand to sport for the prop as we now the prop is very delicate.

  2. Determination of the solubility of calcium hydroxide

    * References to the rough titre should be made throughout the course of the experiment. This will ensure that the same PH range is maintained. * Continue to maintain the three drops of Methyl Orange indicator. * I will use the rough titre as the suitable reference for the suitable colour change.

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