The Effect of Ionic Strength on the Solubility of an Electrolyte
Title of Experiment 12:
The Effect of Ionic Strength on the solubility of an Electrolyte
Aim:
The purpose of this experiment was to determine the thermodynamics variable of enthalpy, ∆H for the dissolution reaction of boric acid in water. The solubility of boric acid was measured over a range of various temperatures by finding out at what temperature crystallization began for solution of different molarities. A graphical relationship between the natural logarithm of molal concentration and the inverse of the temperature gave a linear plot to determine the enthalpy changes associated with the reaction.
Methodology:
The procedure was carried out as follows in the CHEM2210 Laboratory Manual from page 58 to 59.
Results
| Weight of conical flask (g) | Weight of Boric Acid (g) | Weight of water (g) | Total weight of conical flasks with boric acid solution (g) | Temperature of boric acid crystallise from solution (°C) | Total weight of conical flasks with boric acid solution at Room Temperature (g) | Total water mass lost
(g) | 1 | 133.738 | 4.506 | 50.021 | 188.265 | 37.4 | 186.447 | 1.818 | | 114.311 | 4.553 | 50.127 | 168.991 | 36.8 | 167.530 | 1.461 | | 115.476 | 4.509 | 50.069 | 170.054 | 37.2 | 169.152 | 0.902 | 2 | 133.558 | 6.108 | 50.147 | 189.813 | 46.5 | 188.306 | 1.507 | | 114.115 | 6.011 | 50.269 | 170.395 | 45.3 | 168.662 | 1.733 | | 115.387 | 6.009 | 50.210 | 171.606 | 45.7 | 170.098 | 1.508 | 3 | 74.593 | 8.042 | 54.712 | 137.347 | 58.5 | 136.689 | 0.658 | | 86.137 | 8.083 | 50.367 | 144.587 | 62.5 | 143.280 | 1.307 | | 63.950 | 8.045 | 50.940 | 122.935 | 59.5 | 121.619 | 1.316 | 4 | 124.694 | 10.342 | 50.321 | 185.357 | 62.8 | 183.362 | 1.995 | | 132.160 | 10.300 | 50.017 | 192.477 | 63.3 | 190.669 | 1.808 | | 115.665 | 10.326 | 50.048 | 176.039 | 64.7 | 174.206 | 1.833 | 5 | 114.297 | 12.003 | 50.019 | 176.319 | 75.2 | 173.379 | 2.940 | | 168.315 | 12.088 | 50.132 | 230.535 | 73.4 | 227.730 | 2.805 | | 111.457 | 12.007 |
The Effect of Ionic Strength on the solubility of an Electrolyte
Aim:
The purpose of this experiment was to determine the thermodynamics variable of enthalpy, ∆H for the dissolution reaction of boric acid in water. The solubility of boric acid was measured over a range of various temperatures by finding out at what temperature crystallization began for solution of different molarities. A graphical relationship between the natural logarithm of molal concentration and the inverse of the temperature gave a linear plot to determine the enthalpy changes associated with the reaction.
Methodology:
The procedure was carried out as follows in the CHEM2210 Laboratory Manual from page 58 to 59.
Results
| Weight of conical flask (g) | Weight of Boric Acid (g) | Weight of water (g) | Total weight of conical flasks with boric acid solution (g) | Temperature of boric acid crystallise from solution (°C) | Total weight of conical flasks with boric acid solution at Room Temperature (g) | Total water mass lost
(g) | 1 | 133.738 | 4.506 | 50.021 | 188.265 | 37.4 | 186.447 | 1.818 | | 114.311 | 4.553 | 50.127 | 168.991 | 36.8 | 167.530 | 1.461 | | 115.476 | 4.509 | 50.069 | 170.054 | 37.2 | 169.152 | 0.902 | 2 | 133.558 | 6.108 | 50.147 | 189.813 | 46.5 | 188.306 | 1.507 | | 114.115 | 6.011 | 50.269 | 170.395 | 45.3 | 168.662 | 1.733 | | 115.387 | 6.009 | 50.210 | 171.606 | 45.7 | 170.098 | 1.508 | 3 | 74.593 | 8.042 | 54.712 | 137.347 | 58.5 | 136.689 | 0.658 | | 86.137 | 8.083 | 50.367 | 144.587 | 62.5 | 143.280 | 1.307 | | 63.950 | 8.045 | 50.940 | 122.935 | 59.5 | 121.619 | 1.316 | 4 | 124.694 | 10.342 | 50.321 | 185.357 | 62.8 | 183.362 | 1.995 | | 132.160 | 10.300 | 50.017 | 192.477 | 63.3 | 190.669 | 1.808 | | 115.665 | 10.326 | 50.048 | 176.039 | 64.7 | 174.206 | 1.833 | 5 | 114.297 | 12.003 | 50.019 | 176.319 | 75.2 | 173.379 | 2.940 | | 168.315 | 12.088 | 50.132 | 230.535 | 73.4 | 227.730 | 2.805 | | 111.457 | 12.007 |
References: Ervin, R. V. A., Keith, P. A. 1951, ‘The Molar Heats of Solution of Boric Oxide and Boric Acid’, Journal of the American Chemical Society, vol. 73 no. 2, pp 579–581. Available from: http://pubs.acs.org/doi/abs/10.1021/ja01146a022 [08 November 2010].