Lab 5: Precipitate Patterns October 31st, 2013 Partners: Muhammad Saeed, Kristian Palmer and Kyle Poirier By: Rauman Tuan-Kichil For: Mr. Fontaine Investigation: Wastewater from metal manufacturing processes often contains toxic cations. These ions must be removed before the water can be released into the environment. Many of these ions can be removed using precipitation reactions. For example, recycled car batteries contain toxic lead cations, Pb 2+. These can be removed by adding a solution of potassium iodide, KI.
One form of extractive metallurgy, called hydrometallurgy, uses aqueous solution chemistry for the recovery of metals from salts minerals or ores. The first step of hydrometallurgy, called extraction, is the process of removing metal from the ore. This is done by dissolving the metal in a suitable solvent, recovering the metal from the solution, and discarding the waste materials. The first step of extraction is leaching, in which the metal is dissolved in water or acid. Then the leach solution is purified by separating the waste from the desired materials.
The reaction that occurred with this step was displacement and metathesis in the form of gas formation. The balanced equation of this step looks as follows: CuSO4aq+Zns→Cus+ZnSO4(aq) Once this step was finished, the remaining copper was retrieved. First, to recover the copper HCl was added to remove all the zinc. When this happened, a yellow tint was observed in the liquid, as well as bubbling as the zinc was broken down. Once the copper dried out, it was weighed and came to a total of 240 mg.
The purpose of the lab was to determine which reactant was the limiting reactant, and to see how much of the other reactant was used. The true molarity of a compound can be defined as the amount of moles per liter of that substance. The equation of this single displacement chemical reaction done during this lab is 2Al(s) + 3CuCl(aq) → 3Cu (s) + 2AlCl2 (aq). In the reaction, the solid Aluminum replaces the Copper in Copper (II) Chloride to produce solid copper, and Aluminum Chloride. In order to find which reactant is the limiting reactant, an equation based on the molarity of the Copper (II) Chloride may be used, or the products of the reaction may be observed.
Results: Zinc Metal - Iodine - Iodide + Triodide + Zinc Ion + Focus Questions: 1. Is there a way to put energy into Zinc Iodide in order to regain the elements, zinc and iodine? If there is a way, how does it happen? Yes, this can be done through electrolysis using a battery and exposed wire tips. Take sample of Zinc Iodide and dissolve in solution.
CHE 111 Laboratory 3 Hydrates Introduction Hydrates Water molecules combine with the molecules of certain substances, forming loose chemical combinations called hydrates. An example of a hydrate is MgSO4•7H2O. This formula means 7 water molecules are loosely attached to a magnesium sulfate molecule. Other examples of hydrates are Na2SO4•10H2O and Ba(OH)2•8H2O. When the hydrate is heated, it easily loses water molecules attached and becomes an anhydrous salt.
Jessica Atanova CHEM 104 lab 03/10/14 SUBSTANCES Granular zinc- gray crystal like | Iodine crystals- dark, circular, rock-like | De-ionized water: used for standard Zinc Ion procedure. | Materials: Boiling tube: for products. | Small test tubes: used to centrifuge the solution and precipitate | Graduated cylinder: used for measurement of water | Stirring rod: used various times to stir samples and solutions. | Spatula: used to measure and transfer the substances. | Centrifuge: used to isolate the solid from the solution | .
The carbon rod is surrounded by a layer of manganese dioxide (MnO2), and a thick paste of ammonium chloride (NH4Cl) and zinc chloride (ZnCl2), which serves as an electrolyte. The oxidation reaction that takes place on the zinc casing is: Zn(s)→Zn+2+2e- While the reduction reaction that takes place on the carbon rod is: 2MnO2+2H+(aq)+2e-→Mn2O3(s)+H2O(l) The overall reaction is: Zn(s)+2MnO2+2NH4+(s)→Mn2O3(s)+Zn(NH3)22+(aq)+H2O(l) The standard dry cell contains 1.5V. The reactions present in dry cells continue until they run out of a reactant (the anode or cathode). However, there are cells that can be recharged, as the redox reaction can be reversed in order to regenerate the original reactants. Some examples of these batteries include lithium batteries and car batteries.
The chemical reaction used to find this constant is as follows: MgC2O4 (s) ↔Mg(aq)2++ C2O4 (aq)2- Kc= Mg2+[C2O42-][MgC2O4] Ksp=Mg2+[C2O42-] The solid salt magnesium oxalate is prepared through the following precipitation reaction: Mg(SO4)(aq)+NaC2O4 (aq) → MgC2O4 (s)+NaSO4 (aq) Next, the concentration of the Mg2+ and C2O42- ions is found through a redox titration. This redox titration uses a standardized potassium permanganate solution. The potassium permanganate solution is standardized by titrating it with samples of iron(II)ammonium sulfate hexahydrate . The end point is reached when the solution has turned light purple which is a result of excess amounts of MNO4-. This reaction can be summed up using the following formula: 5Fe2++8H++MnO4- →5Fe3++Mn2++4H2O After standardization, the potassium permanganate solution is then titrated with 3 different magnesium oxalate solutions.
c. It burns in an atmosphere of chlorine. d. It is one of the few substances that expands upon freezing. e. The gray form melts at 631°C. 2. The following properties describe zinc.