Determining The Enthalpy Change Of The Decompositi

Determining the Enthalpy Change of the decomposition of sodium hydrogen carbonate (conclusion + evaluation)
Conclusion
I found that ?H1 = 23.4 kJ/mol and ?H2 = 20.6 kJ/mol
2NaHCO3(s) ? Na2CO3(s) + H2O(l) + carbonic acid gas(g)
response 1: 2NaCl(aq) + CO2(g) + H2O(l) ? 2HCL(aq) + Na2CO3 (-?H)
Reaction 2: 2HCl(aq) + 2NaHCO3(s) ? 2NaCl(aq) + 2H2O(l) + 2CO2(g) (2 x ?H)
The HCl, NaCl, H2O and CO2 cornerstonecel out to leave: 2NaHCO3(s) ? Na2CO3(s) + H2O(l) + CO2(g)
Therefore: ?Hr = 2 x ?H2 + (-?H1)
= 2 x 23.4 + 20.6 = 67.4 ± 2.3 (3.46%) kJ/mol = ?Hr
?Hr is exacting which means that that the reaction is end early(a)mic i.e. energy was taken in from the surroundings. In other words more energy was exhausted breaking bonds, which require energy to be taken in, than qualification them, which releases energy.
The literature value was found to be 90.0 kJ/mol
Therefore the data-based misplay is: 90.0-67.490.0=25.1 %
Since 25.1% > 3.46% (the apparatus error) there must have been other errors with the experiment itself to cause this.
Evaluation
The specific heat capacity and the density of HCl were taken as the respective set for water. This would create a result for Q which is not completely reliable (as the values for c and m would not be correct).



We could improve this by working(a) out the specific heat capacities 1.00 mol dm-3 HCl.
The parallax error is a fault in this experiment, the thermometer suffered from this effect. Results can be higher than anticipate when one looks tries to reach eye level one can go below eye level and read the values incorrectly. The variations in viewing angles would cause series of random errors. This error could be improved by the use of a digital thermometer which would negate the parallax error all together; with a digital thermometer readings would also be more precise as wellhead as more accurate.
The stirring happened inconsistently and thus added a series of boosts of kinetic energy for the molecules rather than a unvarying stream of kinetic energy. This...If you want to get a just essay, order it on our website: Ordercustompaper.com



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