Chem 142 Lap Postlab Report #2

Chem 142 Lap Postlab Report #2 - EXPERIMENT 2 Chemical...

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EXPERIMENT 2: Chemical Composition of Compounds I. IDENTIFICATION BASED ON PERCENT METAL COMPOSITION DATA I. Magnesium Mass of empty crucible and cover: 21.47 g Mass of crucible, cover, and Mg: 21.65 g Mass of Mg: 0.18 g Mass of crucible, cover, and product: 21.71 g Mass of product: 0.24 g II. Copper Mass of empty crucible and cover: 17.43 g Mass of crucible, cover, and sample: 18.43 g Mass of sample: 1 g Mass of crucible, cover, and product: 18.1 g Mass of product: 0.67 g Mass of crucible and cover : 18.7 g Mass of crucible, cover, and KCl/KClO3 mixture: 19.7 g Mass of KCl/KClO3 mixture: 1 g Mass of crucible, cover, and product: 19.31 g Mass lost upon heating : 0.38 g II. DETERMINATION OF PERCENT KClO 3 IN A KClO 3 /KCl MIXTURE III. KCl/KClO 3 mixture Purpose and Method Things to think about: What is the goal of this experiment? Explain how it is accomplished. What is the general method (not step by step detailed procedure) that you will be using to achieve this goal? How will you process the data that you record in lab? (What calculations will you use and how do you obtain all of the values to plug into those equations?) In this experiment, Mg is strong heated until it fully reacts with a component of air (oxygen or nitrogen). Explain how percent Mg is determined. Also explain how percent Mg is used to distinguish between MgO and Mg 3 N 2 . (2 pts) The % Mg is determined by dividing the dividing the mass of the Mg by the mass of the product and multiplying that answer by 100%. The equation should be as followed: % Mass Mg = mass of Mg x 100% mass of product This % Mg allows you to identify the product as being either MgO or Mg3N2 by comparing the experimental %Mg value to the theoretical % Mg values for both MgO and Mg3N2, which you'd be able to calculate by dividing the molar mass of Mg by the molar mass of the compound that the % mass is being compared to: % Mg = mass of Mg x 100% molar mass of compound How is percent Cu determined in the copper carbonate hydroxide compounds? (2 pts) First of all, you must calculate the mass of Cu in the product by multiplying the mass of CuO product with the percent Cu in CuO which can be calculated with this equation: From this calculated mass of the original sample and the mass of the Cu found in the product, the % Cu in the unknown sample can be determined by dividing the mass of Cu in the sample by the mass of the reactant, and multiplied with 100% : % Cu in sample = mass of Cu in sample_____ x 100% mass of reactant How is percent KClO
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Chem 142 Lap Postlab Report #2 - EXPERIMENT 2 Chemical...

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