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

Determining and comparing the heats of combustions of alcohols

Extracts from this document...


Anupma Raj-12i May 7, 2007 WHICH ALCOHOL IS THE BEST FEUL BETWEEN METHANOL, ETHANOL AND PROPANOL? INTRODUCTION: In this experiment I will determine the amount of heat energy involved in a chemical change. When an alcohol burns it produces carbon dioxide and water as products. Energy is also released in the reaction. I will be determining the amount of heat liberated when three alcohols burn, and compare their energy output, i.e. their heat of combustion. We will be using methanol CH3OH , ethanol C2H5OH , and propan-1-ol CH3CHOHCH3/C 3H 7OH. RESEARCH QUESTION: To investigate which alcohol gives out most energy per gram/mol/cm3 and hence, is the best fuel. HYPOTHESIS: I think that propan-1-ol will give out the most energy during combustion followed by ethanol and then methanol and hence, propan-1-ol will be the best fuel. During complete combustion of an alcohol, the energy is produced from formation of combustion products CO2 and H2O. Thus, Heat of Combustion should increase approximately linearly with the number of Alcohol Carbon atoms and as the formula suggests, propan-1-ol has more carbon atoms than methanol and ethanol. ...read more.


Change in temperature = (16.4+15.9)/2 = 16.15�C or 16.15K Mass of water used = 100ml = 0.1kg Specific Heat Capacity of Water: 4200J/KgK Therefore, energy change = 16.15 x 0.1 x 4200 = 6783J. Mass of methanol alcohol used is (1.099+1.107)/2 = 1.103g Therefore, the amount of energy given out for 1.103g is 6783J. Number of moles propan-1-ol used = (mass/molar mass) = 1.103/32.05 =0.0344 moles Therefore, 0.03440 moles --> 6783J 1 moles --> (6783/0.0344) = 197180.23J = 197.2kJ Energy change of Copper Calorimeter = mass x specific heat capacity x change in temperature. Change in temperature = change in temperature of water (ASSUMING) = 16.15K Mass of copper calorimeter = 186 g = 0.186kg Specific Heat Capacity of Copper: 390J/KgK Therefore, energy change = 16.15 x 0.186 x 390 = 1171.52J = 1.17kJ Total energy change = 197.2kJ + 1.17kJ = 198.4kJ Therefore, the total energy change for methanol is -198.4kJ. The value is negative because the energy is given out (as we can feel the energy being radiated when we are heating the water and hence, we know the reaction is exothermic). ...read more.


While measuring the heat transfer from the flame to the copper calorimeter, a lot of heat was lost to the environment. The experiment was designed such that this was an inevitable error. 2. We were measuring the volume of water in the measuring cylinder as a lot of bubbles formed which prevented the accurate measurement of the volume. 3. We kept the room ventilated as the flow of air cooled down the copper calorimeter and hence, we did not get a precise reading for the temperatures. 4. We assumed that there would be complete conversion to heat energy when the alcohols were burnt. 5. We assumed that the change in temperature of water equaled the change in temperature of the alcohol. IMPROVEMENTS: Here are a few improvements we could make: 1. To prevent the formation of bubbles while measuring the volume of water, we could pour the water from the tap into the measuring cylinder very slowly so as to reduce the chances of the formation of bubbles. 2. We could place some sort of blockage such as a glass shield around the flame/experiment to prevent the air flow in the room from affecting the results of the experiment. 3. We could take more trials so as to reduce the systematic errors and obtain more precise and accurate results. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate 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 International Baccalaureate Chemistry essays

  1. Enthalpy of Combustion of Alcohols Lab

    + (3 x 1) + (16) + (1) M = 32.0 gmol-1 m = 1.53 g n = 1.53g/32.0 gmol-1 n = 0.0480 mol Step 2: Calculating heat energy given out Q = mC?T m = 100g C = 4.186 Jg-1k-1 ?T = 11.5k Q = (100g)

  2. The purpose of this experiment was to determine the molar mass of carbon dioxide ...

    (Mass of flask + CO2) - Mass of flask = mass if CO2 48.360 g - 48.173387 g = 0.18661 g 5) Calculating the molar mass of carbon dioxide. Once all the calculations were done, enough information was retrieved to deduce the mass of carbon dioxide through the ideal gas law equation (PV = nRT)

  1. Lab 1 - Determining Hydrate Formulas

    Sulfate (ZnSO4) with the crucible and the lid. So my answer in the end for the hydrate turned out to be in decimals. My ratio for the hydrate to the dehydrated Zinc (II) Sulfate (ZnSO4) became 0.66:1. Then I realized that hydrates can't be in decimals, and as I scanned the data chart again and again I found

  2. Free essay

    Vitamin C in Fruit Juices

    International source their fruit from and there could have been varying vitamin C contents in the fruit used and the early stages of production hence the surprising results found for the Pine Orange and Orange Fruit Drinks. Parameters used for processing into different products: Frozen concentrated orange juice (FCOJ)

  1. Investigating the effect of different liquid densities on the time taken to release ...

    Attach the burette to the retort stand and take care that the burette is upright and stable. 3. Close the tap and use the funnel to put 25 ml of ethanol into the burette. 4. Remove the funnel, make sure that there is no air bubble inside the burette.

  2. Electrolysis of copper sulphate

    This would have also contributed to reducing our measurement for the mass gained. Copper sulphate solution was not replaced after each test. This could have led to the solution having excess amounts of copper in the solution, which, may have inhibited electrolysis and may well have had an effect on the amount of copper deposited on the cathode.

  1. The aim of this experiment is to examine the enthalpy of combustion of the ...

    The flame was light orange. Incomplete transmission of heat is assumed due to the movements caused in the laboratory, which affected the flame and therefore the transmission. Qualitative data Mass of butanol Mass 1 Mass 2 Mass 3 Average mass Initial mass g ± 0.01 125.43 147.35 136.14 136.30 Final mass g ± 0.01 124.04

  2. Bomb calorimetry. The goal of this experiment was to use temperature data over ...

    By definition of enthalpy, this in the present case is enthalpy of combustion: âH = âU + â (pV) =âU + â (nRT) = âU + â ngas RT (8) âH and âU would be identical only if the pressure in the bomb remains constant.

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