Factors affecting solubility
...een the solution system and its immediate surrounding environment.Some solutions absorb energy as they are formed.The solution is said to have an exothemic heat of solution. Solute + Solvent + Thermal energy →Solution Most aqueous solutions involving liquid or solid solutes will have endothermic heat of solution.However,a few are exceptions to this statement. Other solution involving gaseous solutes in water will release thermal energy during the solution formation process.These solutions are said to have an exothermic heat of solution. Solute(g) + Solvent = Solution + Thermal Energy Within any solution there are electrical interactions called intermolecular forces between the solute and solvent molecules that are also polar. To say that ‘like dissolves like’ means that polar dissolves polar and ionic and nonpolar disolves nonpolar.Water is polar and will form attraction to other polar substances but will not form attractions to nonpolar solutes.Water dissolves ionic compounds, substances that canhydrogen band. Nonpolar solutes interfere with the attractions between water molecules without adding attractions of their own.So the water molecules will just push the nonpolar molecules out.For example, oil/water. The property of various liquids that allows them to be dissolve in each other whatever the proportions of the component is called miscible. Substances that can not be mixed together are immiscible. Solvation is chemical process in which solvent molecules and molecules and ionsof the solute combine to form a compound. Hydration is a solvation process in which water is the main solvent. Objective The purpose of experiment-a is to enderstand how solutions form. The purpose of experiment-b is to define the solubility and to describe the factor that affect the solubility. Materials Experiment-a Experiment-b 1. Test tube rack 1. A beaker 2. Test tube 2. A thermometer 3. Dropper 3. Test tube 4. Water (solvent 4. Utility clamp 5. Alcohol (C2H5OH)(solvent) 5. Stirrer 6. Cloroform (CHCl3)(solvent) 6. Hot plate 7. NaCl (solute) 7. KNO3 (solute) 8. Na2SO4 (solute) 8. Distilled water (solvent) 9. I2 (solute) 10. C12H22O11 (solute) Procedure Experiment-a : Nature of solute and solvent At room temperature the solubility of sugar(C12H22O11), Na2SO4, NaCl and I2 will be test in each of water, alcohol (C2H5OH), cloroform (CHCl3). 1. Solvents is put into the test tubes (for each solvent, four test tube is used.) 2. Solutes is put into the test tubes (for each solvent four different solutes is used.) 3. The results of these tests are recorded designating the subtances as soluble,slightly soluble,or insoluble in each of the solvents. Experiment-b : Effect of temperature How temperature factor can affect the solubility of KNO3 in water will be observed. 1. A beaker is filled three_fourths full of tap water.A temperature is placed in it and recorded the temperature of water. 2. In a test tube two grams of KNO3 is put. 3. Onto this solute, 5mL distilled water is added and the contents is stirred with a stirrer. 4. The test tube is placed in the beaker by the help of utility clamp. 5. If the solute dissolves or not is observed.And ıf it dissolve in water how uch of it dissolved is recorded. 6. It is started heating the beaker 7. The temperature when KNO3 completely dissolves is recorded. 8. The test tube is taken out of the beaker and it is started cooling it down. 9. The temperature when crystallization starts is recorded. Observations Experiment-a 1. In water : sugar dissolved. Na2SO4 less dissolved to the sugar. Most of NaCl didn’t dissolve. I2 didn’t dissolve. 2. In alcohol : all of sugar molecules were dissolve. Na2SO4 molecules didn’t dissolve. NaCl didn’t dissolve. Almost all I2 were dissolved. 3. In Cloroform : sugar less dissolved. Na2SO4 NaCl,almost no molecules dissolved. All I2 molecules dissolved. Experiment-b 1.KNO3 dissolved at 320C temperature. 2.KNO3 crystallized at 140C temperature. Conclusion As doing this experiment there was some points that sohould not be ignored.Likewise,in the experiment-a, i used a very small lump of solute not more than half size of pea.In experiment-b,to dissolve the solute completely as heating the water in which the test tube was,i stirred up the solute.In experiment-b,i observed countinuously the temperature and i pay attention not to miss the true temperatur of the solute dissolved and crystallized. Results & Discussion From this experiment significant results are obtained. There are three factors that explain why solubilities will vary even within the same solution. 1. Nature of solute and solvent- The molecular size of the solute molecules will affect the solubility. The larger the solute molecules the more likely the solubility will diminish. In addition, the polar nature of the solute molecules compared to the solvent will also alter...