The change in enthalpy for the combustion of magnesium metal Essay exam

The change in enthalpy for the burning at the stake of magnesium surfaceAbstract========Hesss law of heat summation states that the appraise of DH for areaction is the same whether it occurs directly or as a serial ofsteps. This principle was used to determine the change in enthalpyfor a extremely exothermic reaction, the combustion of magnesium metal. Enthalpy changes for the reactions of Mg in HCl (aq) and MgO (s) inHCl (aq) were determined experiment entirelyy, then added to that for thecombustion of hydrogen gas to arrive at a value of587 kJ/mol Mg. Compared with the accepted value of 601.8 kJ/mol Mg,our experimental error was 2.46%.IntroductionIn this investigation the change in enthalpy leave be determined fromthe following equation 2Mg + O2 2MgO, but in an indirect manner. Magnesium metal burns with a bright extremely hot firing to firemagnesium oxide. It would be difficult to measure the heat of thereaction since the reaction is rapid and occurs at a high temperature (LeMay et al, 1996). So, to determine the change in enthalpy we willemploy Hesss Law of heat summation It states that the value of DHfor a reaction is the same whether it occurs directly or as a seriesof steps (LeMay et al, 1996). We will perform the two followingreactions Mg + 2HCl MgCl2 + H2 andMgO + 2HCl MgCl2 + H2O, determine their enthalpy changes (DHs), andthey will then be added to that of a given equation, the combustionof water, H2 + 1/2 O2 H2O DH=-285.5 kJ/mol.In this investigation we will be working with potentially dangerouschemicals and safety precautions must be made. Magnesium oxide is arespiratory and eye irritant, the dust must not be inhaled and allwork with MgO should be conducted in the fume hood ( Cartwright,... ...te, only having a 2.46% error. These errors may be accounted for by inaccurate measurements,mathematical mistakes, incomplete reactions, poor heat collection,incorrect recording of data, and poorly calibrated tools. To avoidsuch error matchless should estimate all materials, check each tool before use,take extra care in reading and recording of measurements, double checkall calculations, and about of all be patient, labs take time and arushed procedure leads to inaccurate data and incorrect analysis. Sources CitedCartwright, H.(last revised 2002, November 5). Chemical and other preventative Information. The material and Theoretical Chemistry Laboratory,Oxford University.online. (accessed 2002,December, 4)LeMay, H.E.,Beall, H., Roblee, K.M., and Brower, D.C. (1996).ChemistryConnections to our changing world, Laboratory Manual. Upper SaddleRiver, NJ Prentice Hall. The change in enthalpy for the combustion of magnesium metal Essay examThe change in enthalpy for the combustion of magnesium metalAbstract========Hesss law of heat summation states that the value of DH for areaction is the same whether it occurs directly or as a series ofsteps. This principle was used to determine the change in enthalpyfor a high ly exothermic reaction, the combustion of magnesium metal. Enthalpy changes for the reactions of Mg in HCl (aq) and MgO (s) inHCl (aq) were determined experimentally, then added to that for thecombustion of hydrogen gas to arrive at a value of587 kJ/mol Mg. Compared with the accepted value of 601.8 kJ/mol Mg,our experimental error was 2.46%.IntroductionIn this investigation the change in enthalpy will be determined fromthe following equation 2Mg + O2 2MgO, but in an indirect manner. Magnesium metal burns with a bright extremely hot flame to producemagnesium oxide. It would be difficult to measure the heat of thereaction since the reaction is rapid and occurs at a high temperature(LeMay et al, 1996). So, to determine the change in enthalpy we willemploy Hesss Law of heat summation It states that the value of DHfor a reaction is the same whether it occurs directly or as a seriesof steps (LeMay et al, 1996). We will perform the two followingreactions Mg + 2HCl MgCl2 + H2 andMgO + 2HC l MgCl2 + H2O, determine their enthalpy changes (DHs), andthey will then be added to that of a given equation, the combustionof water, H2 + 1/2 O2 H2O DH=-285.5 kJ/mol.In this investigation we will be working with potentially dangerouschemicals and safety precautions must be made. Magnesium oxide is arespiratory and eye irritant, the dust must not be inhaled and allwork with MgO should be conducted in the fume hood ( Cartwright,... ...te, only having a 2.46% error. These errors may be accounted for by inaccurate measurements,mathematical mistakes, incomplete reactions, poor heat collection,incorrect recording of data, and poorly calibrated tools. To avoidsuch error one should label all materials, check each tool before use,take extra care in reading and recording of measurements, double checkall calculations, and most of all be patient, labs take time and arushed procedure leads to inaccurate data and incorrect analysis. Sources CitedCartwright, H.(last revised 2002, November 5). Chemical and otherSafety Information. The Physical and Theoretical Chemistry Laboratory,Oxford University.online. (accessed 2002,December, 4)LeMay, H.E.,Beall, H., Roblee, K.M., and Brower, D.C. (1996).ChemistryConnections to our changing world, Laboratory Manual. Upper SaddleRiver, NJ Prentice Hall.