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

Chemistry Lab. Deducing Enthalpy of Combustion of Magnesium Oxide with Hesss Law

Extracts from this document...

Introduction

Lab 7: Deducing Enthalpy if Combustion of Magnesium Oxide with Hess's Law Background: Hess's law enables us to determine enthalpy of a reaction. It states that the enthalpy of a reaction is independent of the route taken to yield the products. Therefore, through this, it is possible for us to obtain enthalpies of reaction, which are otherwise difficult to measure by using the enthalpies of reactions. Aim/ Purpose: To deduce the enthalpy of the oxidation of Magnesium by means of Hess's law and the measured enthalpy's of reaction of Magnesium with Hydrochloric acid, and reaction of Magnesium Oxide with Hydrochloric acid and the formation of water. Hypothesis: A prediction was made that the value of reaction enthalpy of oxidization of Magnesium would be approximately -601.8 KJ/ mol, which is the accepted value. (Source of accepted value of oxidization of Magnesium: IUPAC) Apparatus: * Standard Thermometer * 1 M HCl * Magnesium Oxide (MgO) ...read more.

Middle

+ H2(g) Processed Data: Table 2. Processed data for the Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g) and MgO(s) + 2HCl(aq) --> MgCl2(aq) + H2O(l) MgO Mg Temperature Change (C ) 7.4 18.8 Moles of HCl 0.04830 0.04779 Moles of 0.01290 0.00864 Limiting Reagent Mg MgO Reaction Enthalpy (KJ/ mol) -115.8 - 434.6 Reaction Enthalpy for Mg(s) + 1/2 O2 (g) --> MgO (s) reaction = -591.4 KJ/ mol Percent Error: (601.8-604.6/601.8) * 100 = 0.46 % Calculations for acquired Processed Data: Using the following reactions, Hess' Law was applied to find out reaction enthalpy of MgO was found indirectly. Also using this formula for reaction enthalpy: ?H= (-Q / n) * Mg(s) + 1/2 O2 (g) --> MgO (s) * MgO(s) + 2HCl(aq) --> MgCl2(aq) + H2O(l) * Mg(s) + 2 HCl(aq) --> MgCl2(aq) + H2(g) * H2(g) + 1/2 O2 (g) --> H2O(l) Temperature change= final temperature - initial temperature = 27.6 -21.6 = 7.4 Moles of HCl = (ml of HCl /1000) ...read more.

Conclusion

Therefore, the Hypothesis proved to be correct, since we got an almost close value. Evaluation: The almost perfect results with a 0.46 % error in this experiment can proved to be a great result for the determination of enthalpy of oxidization of Magnesium. Numerous errors could have been affected the results achieved in this experiment. The likeliness of heat loss from the probe itself and heat loss into the system could affect the enthalpy of reaction of MgO and Mg with HCl. Another error could be that the specific heat capacity used was for water when in the liquid was solution had other impurities in it, which could have resulted in the slightly off results. These errors could be avoided in other experiments by making use of an insulated cup and by considering the proper specific heat capacity of solutions used in the experiment. The lab also faced the plight of not being experimented under standard conditions. ?? ?? ?? ?? Samhitha Kumbhajadala Lab Partners: Sung Jin Kim Mr. Kuijlaars Chemistry HL 3rd March 2012 ...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. Experiment - The Empirical Formula of Magnesium Oxide

    There are outlier points in the graph. The most obvious one could have affected the value of the gradient. In addition, the correlation coefficient (R2) is 0.5751, which is away from 1, indicating not all the points lie on the linear line.

  2. Enthalpy of Combustion Lab Report

    155.75 - 154.44 = 1.31 51.1 - 44.3 = 6.8 For all five cases, molar mass of ethanol Mm, C2H5OH Amount of ethanol burnt = MF/Mm = A1, Heat energy required to raise the temperature of water by TF = M3 ?

  1. Enthalpy of Combustion of Alcohols Lab

    three alcohols underwent combustion for 1 minute 30 seconds QUALITATIVE DATA: Methanol Ethanol Butan-1-ol 1. Yellow/Orange flame 2. The methanol lamp was warmer when we reweighed it. 1. Yellow flame 2. The water beaker turned black/gray at the bottom due to combustion 3.

  2. Acids/Bases Design Lab. How does a change in the pH value of a solution ...

    Qualitative observations were recorded. 10. Another clean, dry, and empty 50cm3 beaker, labeled 'Beaker BRT1' was massed out on the electronic milligram balance. Its mass was recorded to the nearest 0.001g. 11. After exactly 1 minute has elapsed, the 50cm3 beaker labeled BT1 was decanted of its hydrochloric acid solution, making sure that the zinc metal strip remained.

  1. IB Chemistry - Charles' Law Lab Report

    so we make the temperature as positive value to calculate easier. Limitation There were few limitations in my experiment. The height difference between at 82? (right after boiling the water) and at 24? (room temperature) was quite strange. According to the theory, at 82?, the height (volume)

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

    24.0 24.0 24.0 0 24.0 24.0 24.0 24.0 15 28.5 29.0 30.5 29.0 30 31.0 33.0 34.0 33.0 45 39.0 36.0 37.0 37.0 60 43.0 45.0 46.5 45.0 75 46.5 47.5 48.0 47.5 90 50.0 52.0 53.0 52.0 105 60.0 61.5 62.0 61.0 120 67.5 66.0 67.5 67.5 135 77.5

  1. Percent Yield Lab. This experiment has proven that KI is the limiting reagent ...

    A suggest of improvement is to be more careful while doing this experiment to ensure that all the solid particles are captured. Also adding more distilled water to the beaker and stirring rod and filtering the solution more times will help increase the percentage yield and make the results more accurate and precise.

  2. Finding thr Percentage Composition of Magnesium Oxide

    Answer the Testable Question that was posed at the beginning of this investigation. Support your answer with evidence.

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