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Introduction

Determining Percentage Yield of a Chemical Reaction AIM (RESEARCH QUESTION) The aim of the experiment is determining the percentage yield of the product (copper), in the reaction of copper chloride with aluminum; and stating weather the reaction is an endothermic or exothermic; beside giving reasons about the outcomes, and defining the errors that affected the overall result. INTRODUCTION The percentage yield is the outcome of the product's actual yield divided by the theoretical yield, and it generally shows the accuracy of the conducted experiment; and the percentage yield can be anything below 100% or higher, and it shows that the closer the percentage yield is to 100%, the more accurate is the experiment. The aim of the experiment is to find out the actual yield of copper when an aluminum foil (8cm x 2cm) is placed on distilled water containing 2.00 grams of copper chloride (there is an uncertainty of 0.01 grams in copper chloride's mass due to the measuring equipment). The theoretical yield can be found by balancing the equation the following reaction's equation: - The reactants are: copper chloride (CuCl2) and aluminum (Al); and the products of the reaction are: aluminum chloride (AlCl3) and copper (Cu). ...read more.

Middle

aluminum chloride + copper Here it's made very clear that the controls are: heat (temperature) and agitating (stirring and may include the other apparatus); the independent variable is aluminum (which excess and can't be effected) and the reason it's added in the solution is to take away the chlorine, but copper's purity is affected if too much aluminum is added to the solution, so it's simply a dependent variable. MATERIALS The materials that are needed to conduct this experiment are: - Goggles and lab coat - Aluminum foil (8cm x 2cm) - 2.00 grams of copper chloride (CuCl2) - Hot plate - Forceps - Distilled water (50 ml) - Two 150 ml glass beakers - 50 ml graduated cylinder - Watch glass - Stirring rod - Tea spoon - Grams measuring scale (balance) that shows up to two decimal places. METHOD The procedure for conducting the experiment: 1. Pour 50ml of distilled water in the glass beaker using the graduated cylinder, then measure 2.00 grams of copper chloride (CuCl2), and dissolve it in the water. 2. Fold an aluminum foil into a strip (8cm x 2cm). ...read more.

Conclusion

water on the mass of copper; when the copper is separated from the solution, it may wasn't absolutely dry and that what caused the copper to be heavier, which is in order what makes the percentage yield too high. Tiny particles of copper chloride were stuck in the tea spoon when transferring 2.00 g of copper chloride into the distilled water; it's the same spoon that is used to transfer the wet solid copper after vaporization from the beaker to the glass watch. CONCLUSION All the results that are gathered shows that the exothermic reaction that based on evidences of color change, bubbling and temperature change went to a completion. However, the conducted experiment includes some kind of errors which leaded to a high percentage yield and an inaccuracy. Some suggestions might apply that help improving the experiment and ending with a more accurate percentage yield, such as: - Using thin papers in separating the copper from the solution instead of boiling, because it makes sure that the copper is dry. - Making sure not to use the same material (apparatus) twice, to avoid errors (e.g. stuck particles on the glass watch could give a heavier mass for copper). ...read more.

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