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

Determination of Heat of Combustion of Ethanol

Extracts from this document...

Introduction

Harshal Patil Determination of Heat of Combustion of Ethanol ________________ Aim In this experiment, I heated water to 40ºC using a with a spirit burner containing ethanol. Then using the mass of ethanol lost while heating the water, I determined the heat of combustion of ethanol. C2H5OH(l) + 3O2(g) ï 2CO2(g) + 3H2O(l) Data Trial 1 Trial 2 Initial Temperature Water (°C) ±0.5 13.0 16.0 Final Temperature Water (°C) ±0.5 53.0 56.0 Volume Water (cm3) ±0.1 200.0 200.0 Initial Mass Spirit Burner (g) ±0.01 184.28 182.13 Final Mass Spirit Burner (g) ±0.01 182.43 180.23 Mass of Ethanol used (g) ±0.02 1.85 1.90 Observations The temperature of the can rises rapidly since it is a good insulator and ash is collected at the bottom of the can turning it black from the outside. The temperature of the water inside rises slowly and after a while there are traces of visible water vapor emerging from the can. ...read more.

Middle

Q = 200.0*4.18*40.0 Q = 33.44 ±0.85 KJ ΔH = Q/n ΔH = 33.44/0.0412 ΔH = -811.65 ±28.44 KJ/mol Average = (833.92+811.65)/2 =-822.79 ±14.89 ΔH of Ethanol = -822.79 ±29.43 KJ/mol Conclusion The aim of the experiment was to find the heat of combustion of ethanol. I found the heat of combustion of ethanol -822.79 ±29.43 KJ/mol. As seen from my percentage error, I can safely say that my experiment was not very successful. The actual value for the heat of combustion of ethanol is -1367 KJ/mol which is quite far away from my experimentally determined value. The percentage error is 39.8% which is much larger than the percentage uncertainty which is 3.65%. There is also a vast difference between the two trials which tells us that the results aren’t very dependable and there is a large uncertainty. All this signals to the fact that there was not only random error but also a significant amount of systematic error. ...read more.

Conclusion

2. Another cause for this error was the flame. The size of the flame changed slightly and the flame moved about a lot due to air movement. Even though I tried to keep the bottom of the can just touching the tip of the flame, it was not possible. Also there was a large amount of energy lost directly from the flame to heat the air surrounding it. This was all caused because the experiment was conducted in a lab full of students and with open doors. I could have done the experiment in a closed box or an empty room with closed doors and windows to reduce these errors. 3. I also observed some soot forming at the bottom of the can which was caused due to incomplete combustion of the ethanol. This means that the energy released during incomplete combustion was lower where as in my experiment I assumed there was only complete combustion. 4. Finally the theoretical value I used is for STP which was not the case in my experiment. Due to this fact the calculations used to determine the heat of combustion of ethanol are not accurate. ...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

    was that a lot of heat was able to escape and therefore, there was less energy while a lot of energy was wasted. Thus, the enthalpy change we found was much lower than the actual value given in the Data Booklet as the enthalpy change of combustion is the absorption

  2. IB IA: Determination of Heat of Neutralization

    Experiment 2: Equation for the experiment: HNO3(aq) + KOH(aq) � KNO3(aq) + H2O(l) Heat evolved = mc? = 0.1 x 4.18 x 5.75 = 2.4035 kJ Number of moles of acids used = 1 x 0.05 = 0.05 moles From the equation, 1 mole of HNO3 reacts with 1 mole of KOH and gives 1 mole of water.

  1. Molar Heat combustion chemistry - investigate the effect of molar mass on the molar ...

    Qualitative Data Alcohol Observations Methanol * Burner not always placed at the same place * Temperature increased quickly. * Soot formed below the can. * The distance between the can and the flame was different for each group and each alcohol Ethanol * The distance between the can and the

  2. Free essay

    How the combustion of different types of food affect the amount of heat calories ...

    7. Hold the piece of food with the tongs. Slide the user-end part of the tongs down the index finger and thumb towards the hand. Using the other hand and the thumb and index fingers from the hand holding the tong, light a match. Hold the match underneath the piece of food until it ignites.

  1. Lab to determine The Specific Heat of a Metal

    100 = 1.5% The absolute uncertainty was divided by the experimental value then multiplied by 100 in order to obtain the percent error for each of volume, temperature, mass, etc. Finding the Quantity of Heat "q" of water q = mc?t qH2O = (100 + .5 % g)

  2. Analysis of Silver in an Alloy

    * To make sure the alloy had totally dissolved, the beaker containing the solution was placed on a hot plate * After calculating two times the amount of sodium chloride necessary to precipitate the silver in the alloy sample (assuming that the sample is 100% silver), the amount of sodium

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

    The volume is constant (calorimeter bomb), and if the heat capacity Ccal of the calorimeter is known, the measurement of the water bath temperature change (âT) provide directly a measurement of the internal change for the system: âcUsample + âcUcotton = -CVâT (7)

  2. Analysis of the Standard Enthalpy of Combustion for Alcohols

    Calculate the average change in mass of each alcohol and calculate the change in temperature of water for each trial. 12. Calculate energy absorbed by this using q=mcâT then calculate âH°comb=qn 13. Plot the graph of âH°combversus number of carbons in alcohol.

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