Hamlet

Objective - Classify the solutions to whether the electrolyte or the non-electrolyte as a pair of electrodes immerse into the solutions and we observe the brightness of light bulb. Introduction - Liquids and solution can be classified according to substances that contained. The substances are divided to two types. When the substances dissolve in a solvent, such as water, if they cause liquids to conduct electricity, they ard called electrolytes. Because the substances have two parts of charged ions which a cation that is positively charged and an anion that is negatively charged, when they are dissolve in water, they ionize in water, and eventually, the liquids change to electrically conductive. For example, when NaCl is dissolved in water, the bond between the Na+ and Cl- ions breaks down and then it is totally ionized. The solution process can be represented as: NaCl(s) + H2O(l) → Na+(aq)+ Cl-(aq) Therefore, NaCl is called strong electrolyte, and it is an example of ionization of ionic compounds which ionize easily in solution. All strong acids and bases dissociate completely into ions in solution. If a covalent compound, such as HCl (g) which is strong acid is dissolved in water, it is represented as : HCl(g) + H2 O(l) → H3O + (aq)+ Cl-(aq) As a result, positive hydronium ions and negative chloride ions ard produced in sufficient quantity to make hydrochloric acid conductive, and a large fraction of the HCl dissolved in water is ionized, producing a large amount of electricty carrying ions. There is also strong base NaOH which is 100% ionized in water and it is represented as : NaOH(s)+H2O → Na+(aq)+OH-(a) For this reason, those strong acid and base are totally ionized in water, and the solution can conduct electricity. Therefore, they are called strong electrolytes. However, there are also weak acidic and base which called weak electrolytes. For example, when NH3 which is weak base is dissolved in water, it can be represented as: NH3(aq)+H2O(l) ↔ NH4+(aq)+OH-(aq) The NH4+ ions and OH-ions are partially dissociated so the solution conducts electricity weakly. For this reason, NH3 is classified as a weak electrolyte. As the same condition, CH3COOH which is weak acid is called a weak electrolyte and the equation is represented as: CH3COOH(aq)+H2O(l) ↔ CH3COO-(aq)+H3O+(aq) Weak electrolytes depend on the concentration of the solution and on the nature of the solute, so the degree of ionization increases with decreasing concentration. Therefore, to dilute ammonia and acetic acid changes electrolyte more stronger than before. There is also non-electrolyte, such as water and glucose (C6H12O6). When glucose is dissolved in water, it exists as molecule state instead of ions in water, so there is any electrical charge in the solution and glucose is called non-electrolyte. Materials Used and Safety Precaution - Chemicals : Distilled water, Tap water, Sodium chloride, Calcium nitrate, Potassium permanganate, Ammonium chloride, Sodium acetate, Hydrochloric acid, 6M, Acetic acid, 6M, Ethanol, Sucrose, Gasoline( a mixture of hydrocarbons), Concentrated ammonia, Dilute amminua, Concentrated acetic acid, Dilute acetic acid. - Equipments : Light bulb, a pair of electrodes, several 100mL beakers -Safety Precautions: Wearing glasses to protect eyes from chemicals. When reuse beaker which used before, it should be cleaned because of an accurate result. When we used ammonia, work under the hood becuase ammonia smells very strong. Procedure 1. A light bulb was connected to a pair of electrodes to test the solutions which were used in the experiment. 2. About 70mL of distilled water which is listed in the tables in the data sheet was poured into a 100mL beaker. 3. The electreodes were immersed into the beaker which contained distilled water, and switch was turned on. 4. The brightness of the light bulb observed and recorded on the data sheet. Its classification was also entered on the data sheet. 5.All solutions which are listed in the tables observed as following same procedures through step 1 to step4, and the results were entered in the data sheet. Discussion