Determination of Percent by Mass of the Composition in a Mixture by Gravimetric Analysis

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Lab 4: Determination of Percent by Mass of the Composition in a Mixture by Gravimetric Analysis Introduction Thermal gravimetric analysis is used to determine the percent by mass is used to determine the percent by mass of a component in a mixture. When a mixture is heated to an appropriately high temperature, one component in the mixture decomposes to form a gaseous compound. The mass of this particular component is related to the mass of the gaseous compound. In this experiment, the percent by mass of sodium hydrogen carbonate (NaHCO3) and potassium chloride (KCl) in a mixture will be determined. Experimental First, we weighed 2 samples, each has 1 gram of NaHCO3-KCl mixture Second, we put the samples in 2 crucibles (A and B) and weighed them. (crucible + sample; WA1 and WB1) Third, we heated both samples on a hot plate for 30 minutes. Fourth, we weighed the samples again (crucible + sample; WA2 and WB2) Lastly, we determined NaHCU3 percentage in the mixture using the following method: WA1 – WA2 x 100% 0.309 WA1 – WA2 x 100% 0.309 * * Results * Theorectically: * Discussion When sodium hydrogen carbonate is heated, new products are formed; sodium carbonate, water vapor, and carbon dioxide gas. This reaction may be presented in a different form with a measure of molecules: @Na2CO3 + H2O + CO2 (solid) (solid) (gas) (gas). Once the reaction of sodium hydrogen carbonate takes place, carbon dioxide gas is released, as well as water vapor. When the compound is under heat, the crystalline power bubbles, and stirs around as the carbon dioxide gas is released. Over time powder is heated, the entire compound gradually decreases noticeably in size and weight as the water vapor escapes as well. The crystalline powder (solid) never changes state, and after